diff --git a/CHANGELOG.md b/CHANGELOG.md
index c26e09255e..d1b7f2d0b3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,7 +23,8 @@
 - Use FORCE_COLOR environmental variable to force colorized output https://github.com/rescript-lang/rescript-compiler/pull/7033
 - Allow spreads of variants in patterns (`| ...someVariant as v => `) when the variant spread is a subtype of the variant matched on. https://github.com/rescript-lang/rescript-compiler/pull/6721
 - Fix the issue where dynamic imports are not working for function-defined externals. https://github.com/rescript-lang/rescript-compiler/pull/7060 
-- Allow pattern matching on dicts. `switch someDict { | dict{"one": 1} => Js.log("one is one") }` https://github.com/rescript-lang/rescript-compiler/pull/7059
+- Allow pattern matching on dicts. `switch someDict { | dict{"one": 1} => Js.log("one is one") }`. https://github.com/rescript-lang/rescript-compiler/pull/7059
+- "ReScript Core" standard library is now included in the `rescript` npm package. https://github.com/rescript-lang/rescript-compiler/pull/7108
 
 #### :bug: Bug fix
 
diff --git a/lib/es6/Array.js b/lib/es6/Array.js
index 794ad95431..5d83e76143 100644
--- a/lib/es6/Array.js
+++ b/lib/es6/Array.js
@@ -1,497 +1,192 @@
 
 
-import * as List from "./List.js";
-import * as Primitive_array from "./Primitive_array.js";
-import * as Primitive_exceptions from "./Primitive_exceptions.js";
+import * as Primitive_option from "./Primitive_option.js";
 
-let init = ((length, f) => Array.from({ length }, f));
-
-function make(len, x) {
-  return init(len, param => x);
-}
-
-function unsafe_sub(array, offset, length) {
-  return array.slice(offset, offset + length | 0);
-}
-
-function concat(list) {
-  return List.fold_left((arr1, arr2) => arr1.concat(arr2), [], list);
-}
-
-function create_float(len) {
-  return init(len, param => 0.0);
-}
-
-function make_matrix(sx, sy, init$1) {
-  let x = [];
-  let res = init(sx, param => x);
-  for (let x$1 = 0; x$1 < sx; ++x$1) {
-    res[x$1] = init(sy, param => init$1);
+function make(length, x) {
+  if (length <= 0) {
+    return [];
   }
-  return res;
+  let arr = new Array(length);
+  arr.fill(x);
+  return arr;
 }
 
-function append(a1, a2) {
-  let l1 = a1.length;
-  if (l1 === 0) {
-    return a2.slice();
-  } else if (a2.length === 0) {
-    return unsafe_sub(a1, 0, l1);
-  } else {
-    return a1.concat(a2);
+function fromInitializer(length, f) {
+  if (length <= 0) {
+    return [];
   }
+  let arr = new Array(length);
+  for (let i = 0; i < length; ++i) {
+    arr[i] = f(i);
+  }
+  return arr;
 }
 
-function sub(a, ofs, len) {
-  if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.sub",
-      Error: new Error()
+function equal(a, b, eq) {
+  let len = a.length;
+  if (len === b.length) {
+    let _i = 0;
+    while (true) {
+      let i = _i;
+      if (i === len) {
+        return true;
+      }
+      if (!eq(a[i], b[i])) {
+        return false;
+      }
+      _i = i + 1 | 0;
+      continue;
     };
+  } else {
+    return false;
   }
-  return unsafe_sub(a, ofs, len);
 }
 
-function fill(a, ofs, len, v) {
-  if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.fill",
-      Error: new Error()
+function compare(a, b, cmp) {
+  let lenA = a.length;
+  let lenB = b.length;
+  if (lenA < lenB) {
+    return -1;
+  } else if (lenA > lenB) {
+    return 1;
+  } else {
+    let _i = 0;
+    while (true) {
+      let i = _i;
+      if (i === lenA) {
+        return 0;
+      }
+      let c = cmp(a[i], b[i]);
+      if (c !== 0) {
+        return c;
+      }
+      _i = i + 1 | 0;
+      continue;
     };
   }
-  for (let i = ofs, i_finish = ofs + len | 0; i < i_finish; ++i) {
-    a[i] = v;
-  }
 }
 
-function blit(a1, ofs1, a2, ofs2, len) {
-  if (len < 0 || ofs1 < 0 || ofs1 > (a1.length - len | 0) || ofs2 < 0 || ofs2 > (a2.length - len | 0)) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.blit",
-      Error: new Error()
-    };
-  }
-  for (let i = 0; i < len; ++i) {
-    a2[ofs2 + i | 0] = a1[ofs1 + i | 0];
+function indexOfOpt(arr, item) {
+  let index = arr.indexOf(item);
+  if (index !== -1) {
+    return index;
   }
+  
 }
 
-function iter(f, a) {
-  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
-    f(a[i]);
+function lastIndexOfOpt(arr, item) {
+  let index = arr.lastIndexOf(item);
+  if (index !== -1) {
+    return index;
   }
+  
 }
 
-function iter2(f, a, b) {
-  if (a.length !== b.length) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.iter2: arrays must have the same length",
-      Error: new Error()
-    };
-  }
-  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
-    f(a[i], b[i]);
-  }
+function reduce(arr, init, f) {
+  return arr.reduce(f, init);
 }
 
-function map(f, a) {
-  let l = a.length;
-  if (l === 0) {
-    return [];
-  }
-  let x = f(a[0]);
-  let r = init(l, param => x);
-  for (let i = 1; i < l; ++i) {
-    r[i] = f(a[i]);
-  }
-  return r;
+function reduceWithIndex(arr, init, f) {
+  return arr.reduce(f, init);
 }
 
-function map2(f, a, b) {
-  let la = a.length;
-  let lb = b.length;
-  if (la !== lb) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.map2: arrays must have the same length",
-      Error: new Error()
-    };
-  }
-  if (la === 0) {
-    return [];
-  }
-  let x = f(a[0], b[0]);
-  let r = init(la, param => x);
-  for (let i = 1; i < la; ++i) {
-    r[i] = f(a[i], b[i]);
-  }
-  return r;
+function reduceRight(arr, init, f) {
+  return arr.reduceRight(f, init);
 }
 
-function iteri(f, a) {
-  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
-    f(i, a[i]);
-  }
+function reduceRightWithIndex(arr, init, f) {
+  return arr.reduceRight(f, init);
 }
 
-function mapi(f, a) {
-  let l = a.length;
-  if (l === 0) {
-    return [];
-  }
-  let x = f(0, a[0]);
-  let r = init(l, param => x);
-  for (let i = 1; i < l; ++i) {
-    r[i] = f(i, a[i]);
+function findIndexOpt(array, finder) {
+  let index = array.findIndex(finder);
+  if (index !== -1) {
+    return index;
   }
-  return r;
+  
 }
 
-function to_list(a) {
-  let _i = a.length - 1 | 0;
-  let _res = /* [] */0;
-  while (true) {
-    let res = _res;
-    let i = _i;
-    if (i < 0) {
-      return res;
-    }
-    _res = {
-      hd: a[i],
-      tl: res
-    };
-    _i = i - 1 | 0;
-    continue;
-  };
+function swapUnsafe(xs, i, j) {
+  let tmp = xs[i];
+  xs[i] = xs[j];
+  xs[j] = tmp;
 }
 
-function list_length(_accu, _param) {
-  while (true) {
-    let param = _param;
-    let accu = _accu;
-    if (!param) {
-      return accu;
-    }
-    _param = param.tl;
-    _accu = accu + 1 | 0;
-    continue;
-  };
+function random_int(min, max) {
+  return (Math.floor(Math.random() * (max - min | 0)) | 0) + min | 0;
 }
 
-function of_list(param) {
-  if (!param) {
-    return [];
+function shuffle(xs) {
+  let len = xs.length;
+  for (let i = 0; i < len; ++i) {
+    swapUnsafe(xs, i, random_int(i, len));
   }
-  let hd = param.hd;
-  let len = list_length(0, param);
-  let a = init(len, param => hd);
-  let _i = 1;
-  let _param = param.tl;
-  while (true) {
-    let param$1 = _param;
-    let i = _i;
-    if (!param$1) {
-      return a;
-    }
-    a[i] = param$1.hd;
-    _param = param$1.tl;
-    _i = i + 1 | 0;
-    continue;
-  };
 }
 
-function fold_left(f, x, a) {
-  let r = x;
-  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
-    r = f(r, a[i]);
-  }
-  return r;
+function toShuffled(xs) {
+  let result = xs.slice();
+  shuffle(result);
+  return result;
 }
 
-function fold_right(f, a, x) {
-  let r = x;
-  for (let i = a.length - 1 | 0; i >= 0; --i) {
-    r = f(a[i], r);
-  }
+function filterMap(a, f) {
+  let l = a.length;
+  let r = new Array(l);
+  let j = 0;
+  for (let i = 0; i < l; ++i) {
+    let v = a[i];
+    let v$1 = f(v);
+    if (v$1 !== undefined) {
+      r[j] = Primitive_option.valFromOption(v$1);
+      j = j + 1 | 0;
+    }
+    
+  }
+  r.length = j;
   return r;
 }
 
-function exists(p, a) {
-  let n = a.length;
-  let _i = 0;
-  while (true) {
-    let i = _i;
-    if (i === n) {
-      return false;
-    }
-    if (p(a[i])) {
-      return true;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
+function keepSome(__x) {
+  return filterMap(__x, x => x);
 }
 
-function for_all(p, a) {
-  let n = a.length;
+function findMap(arr, f) {
   let _i = 0;
   while (true) {
     let i = _i;
-    if (i === n) {
-      return true;
+    if (i === arr.length) {
+      return;
     }
-    if (!p(a[i])) {
-      return false;
+    let r = f(arr[i]);
+    if (r !== undefined) {
+      return r;
     }
     _i = i + 1 | 0;
     continue;
   };
 }
 
-function mem(x, a) {
-  let n = a.length;
-  let _i = 0;
-  while (true) {
-    let i = _i;
-    if (i === n) {
-      return false;
-    }
-    if (a[i] === x) {
-      return true;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
+function last(a) {
+  return a[a.length - 1 | 0];
 }
 
-function memq(x, a) {
-  let n = a.length;
-  let _i = 0;
-  while (true) {
-    let i = _i;
-    if (i === n) {
-      return false;
-    }
-    if (x === a[i]) {
-      return true;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
-}
-
-let Bottom = /* @__PURE__ */Primitive_exceptions.create("Array.Bottom");
-
-function sort(cmp, a) {
-  let maxson = (l, i) => {
-    let i31 = ((i + i | 0) + i | 0) + 1 | 0;
-    let x = i31;
-    if ((i31 + 2 | 0) < l) {
-      if (cmp(Primitive_array.get(a, i31), Primitive_array.get(a, i31 + 1 | 0)) < 0) {
-        x = i31 + 1 | 0;
-      }
-      if (cmp(Primitive_array.get(a, x), Primitive_array.get(a, i31 + 2 | 0)) < 0) {
-        x = i31 + 2 | 0;
-      }
-      return x;
-    }
-    if ((i31 + 1 | 0) < l && cmp(Primitive_array.get(a, i31), Primitive_array.get(a, i31 + 1 | 0)) < 0) {
-      return i31 + 1 | 0;
-    }
-    if (i31 < l) {
-      return i31;
-    }
-    throw {
-      RE_EXN_ID: Bottom,
-      _1: i,
-      Error: new Error()
-    };
-  };
-  let trickle = (l, i, e) => {
-    try {
-      let _i = i;
-      while (true) {
-        let i$1 = _i;
-        let j = maxson(l, i$1);
-        if (cmp(Primitive_array.get(a, j), e) <= 0) {
-          return Primitive_array.set(a, i$1, e);
-        }
-        Primitive_array.set(a, i$1, Primitive_array.get(a, j));
-        _i = j;
-        continue;
-      };
-    } catch (raw_i) {
-      let i$2 = Primitive_exceptions.internalToException(raw_i);
-      if (i$2.RE_EXN_ID === Bottom) {
-        return Primitive_array.set(a, i$2._1, e);
-      }
-      throw i$2;
-    }
-  };
-  let bubble = (l, i) => {
-    try {
-      let _i = i;
-      while (true) {
-        let i$1 = _i;
-        let j = maxson(l, i$1);
-        Primitive_array.set(a, i$1, Primitive_array.get(a, j));
-        _i = j;
-        continue;
-      };
-    } catch (raw_i) {
-      let i$2 = Primitive_exceptions.internalToException(raw_i);
-      if (i$2.RE_EXN_ID === Bottom) {
-        return i$2._1;
-      }
-      throw i$2;
-    }
-  };
-  let trickleup = (_i, e) => {
-    while (true) {
-      let i = _i;
-      let father = (i - 1 | 0) / 3 | 0;
-      if (i === father) {
-        throw {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "Array.res",
-            294,
-            4
-          ],
-          Error: new Error()
-        };
-      }
-      if (cmp(Primitive_array.get(a, father), e) >= 0) {
-        return Primitive_array.set(a, i, e);
-      }
-      Primitive_array.set(a, i, Primitive_array.get(a, father));
-      if (father <= 0) {
-        return Primitive_array.set(a, 0, e);
-      }
-      _i = father;
-      continue;
-    };
-  };
-  let l = a.length;
-  for (let i = ((l + 1 | 0) / 3 | 0) - 1 | 0; i >= 0; --i) {
-    trickle(l, i, Primitive_array.get(a, i));
-  }
-  for (let i$1 = l - 1 | 0; i$1 >= 2; --i$1) {
-    let e = Primitive_array.get(a, i$1);
-    Primitive_array.set(a, i$1, Primitive_array.get(a, 0));
-    trickleup(bubble(i$1, 0), e);
-  }
-  if (l <= 1) {
-    return;
-  }
-  let e$1 = Primitive_array.get(a, 1);
-  Primitive_array.set(a, 1, Primitive_array.get(a, 0));
-  Primitive_array.set(a, 0, e$1);
-}
-
-function stable_sort(cmp, a) {
-  let merge = (src1ofs, src1len, src2, src2ofs, src2len, dst, dstofs) => {
-    let src1r = src1ofs + src1len | 0;
-    let src2r = src2ofs + src2len | 0;
-    let _i1 = src1ofs;
-    let _s1 = Primitive_array.get(a, src1ofs);
-    let _i2 = src2ofs;
-    let _s2 = Primitive_array.get(src2, src2ofs);
-    let _d = dstofs;
-    while (true) {
-      let d = _d;
-      let s2 = _s2;
-      let i2 = _i2;
-      let s1 = _s1;
-      let i1 = _i1;
-      if (cmp(s1, s2) <= 0) {
-        Primitive_array.set(dst, d, s1);
-        let i1$1 = i1 + 1 | 0;
-        if (i1$1 >= src1r) {
-          return blit(src2, i2, dst, d + 1 | 0, src2r - i2 | 0);
-        }
-        _d = d + 1 | 0;
-        _s1 = Primitive_array.get(a, i1$1);
-        _i1 = i1$1;
-        continue;
-      }
-      Primitive_array.set(dst, d, s2);
-      let i2$1 = i2 + 1 | 0;
-      if (i2$1 >= src2r) {
-        return blit(a, i1, dst, d + 1 | 0, src1r - i1 | 0);
-      }
-      _d = d + 1 | 0;
-      _s2 = Primitive_array.get(src2, i2$1);
-      _i2 = i2$1;
-      continue;
-    };
-  };
-  let isortto = (srcofs, dst, dstofs, len) => {
-    for (let i = 0; i < len; ++i) {
-      let e = Primitive_array.get(a, srcofs + i | 0);
-      let j = (dstofs + i | 0) - 1 | 0;
-      while (j >= dstofs && cmp(Primitive_array.get(dst, j), e) > 0) {
-        Primitive_array.set(dst, j + 1 | 0, Primitive_array.get(dst, j));
-        j = j - 1 | 0;
-      };
-      Primitive_array.set(dst, j + 1 | 0, e);
-    }
-  };
-  let sortto = (srcofs, dst, dstofs, len) => {
-    if (len <= 5) {
-      return isortto(srcofs, dst, dstofs, len);
-    }
-    let l1 = len / 2 | 0;
-    let l2 = len - l1 | 0;
-    sortto(srcofs + l1 | 0, dst, dstofs + l1 | 0, l2);
-    sortto(srcofs, a, srcofs + l2 | 0, l1);
-    merge(srcofs + l2 | 0, l1, dst, dstofs + l1 | 0, l2, dst, dstofs);
-  };
-  let l = a.length;
-  if (l <= 5) {
-    return isortto(0, a, 0, l);
-  }
-  let l1 = l / 2 | 0;
-  let l2 = l - l1 | 0;
-  let x = Primitive_array.get(a, 0);
-  let t = init(l2, param => x);
-  sortto(l1, t, 0, l2);
-  sortto(0, a, l2, l1);
-  merge(l2, l1, t, 0, l2, a, 0);
-}
-
-let fast_sort = stable_sort;
-
 export {
   make,
-  create_float,
-  init,
-  make_matrix,
-  append,
-  concat,
-  sub,
-  fill,
-  blit,
-  to_list,
-  of_list,
-  iter,
-  iteri,
-  map,
-  mapi,
-  fold_left,
-  fold_right,
-  iter2,
-  map2,
-  for_all,
-  exists,
-  mem,
-  memq,
-  sort,
-  stable_sort,
-  fast_sort,
+  fromInitializer,
+  equal,
+  compare,
+  indexOfOpt,
+  lastIndexOfOpt,
+  reduce,
+  reduceWithIndex,
+  reduceRight,
+  reduceRightWithIndex,
+  findIndexOpt,
+  filterMap,
+  keepSome,
+  toShuffled,
+  shuffle,
+  findMap,
+  last,
 }
 /* No side effect */
diff --git a/lib/es6/ArrayBuffer.js b/lib/es6/ArrayBuffer.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/ArrayBuffer.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/AsyncIterator.js b/lib/es6/AsyncIterator.js
new file mode 100644
index 0000000000..2fb3590e1a
--- /dev/null
+++ b/lib/es6/AsyncIterator.js
@@ -0,0 +1,43 @@
+
+
+import * as Primitive_option from "./Primitive_option.js";
+
+function value(v) {
+  return {
+    done: false,
+    value: Primitive_option.some(v)
+  };
+}
+
+function done(finalValue) {
+  return {
+    done: true,
+    value: finalValue
+  };
+}
+
+async function forEach(iterator, f) {
+  let iteratorDone = false;
+  while (!iteratorDone) {
+    let match = await iterator.next();
+    f(match.value);
+    iteratorDone = match.done;
+  };
+}
+
+let make = (function makeAsyncIterator(next) {
+  return {
+    next,
+    [Symbol.asyncIterator]() {
+      return this;
+    }
+  }
+});
+
+export {
+  make,
+  value,
+  done,
+  forEach,
+}
+/* No side effect */
diff --git a/lib/es6/BigInt.js b/lib/es6/BigInt.js
new file mode 100644
index 0000000000..483f59a0eb
--- /dev/null
+++ b/lib/es6/BigInt.js
@@ -0,0 +1,16 @@
+
+
+
+function toInt(t) {
+  return Number(t) | 0;
+}
+
+function lnot(x) {
+  return x ^ -1n;
+}
+
+export {
+  toInt,
+  lnot,
+}
+/* No side effect */
diff --git a/lib/es6/BigInt64Array.js b/lib/es6/BigInt64Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/BigInt64Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/BigUint64Array.js b/lib/es6/BigUint64Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/BigUint64Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/Console.js b/lib/es6/Console.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Console.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/DataView.js b/lib/es6/DataView.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/DataView.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Date.js b/lib/es6/Date.js
new file mode 100644
index 0000000000..8c66aa05db
--- /dev/null
+++ b/lib/es6/Date.js
@@ -0,0 +1,20 @@
+
+
+import * as Primitive_float from "./Primitive_float.js";
+
+let UTC = {};
+
+function equal(a, b) {
+  return a.getTime() === b.getTime();
+}
+
+function compare(a, b) {
+  return Primitive_float.compare(a.getTime(), b.getTime());
+}
+
+export {
+  UTC,
+  equal,
+  compare,
+}
+/* No side effect */
diff --git a/lib/es6/Dict.js b/lib/es6/Dict.js
new file mode 100644
index 0000000000..4d12162214
--- /dev/null
+++ b/lib/es6/Dict.js
@@ -0,0 +1,30 @@
+
+
+
+function $$delete$1(dict, string) {
+  delete(dict[string]);
+}
+
+function forEach(dict, f) {
+  Object.values(dict).forEach(value => f(value));
+}
+
+function forEachWithKey(dict, f) {
+  Object.entries(dict).forEach(param => f(param[1], param[0]));
+}
+
+function mapValues(dict, f) {
+  let target = {};
+  forEachWithKey(dict, (value, key) => {
+    target[key] = f(value);
+  });
+  return target;
+}
+
+export {
+  $$delete$1 as $$delete,
+  forEach,
+  forEachWithKey,
+  mapValues,
+}
+/* No side effect */
diff --git a/lib/es6/Error.js b/lib/es6/Error.js
new file mode 100644
index 0000000000..a7b7eb76c0
--- /dev/null
+++ b/lib/es6/Error.js
@@ -0,0 +1,29 @@
+
+
+
+let $$EvalError = {};
+
+let $$RangeError = {};
+
+let $$ReferenceError = {};
+
+let $$SyntaxError = {};
+
+let $$TypeError = {};
+
+let $$URIError = {};
+
+function panic(msg) {
+  throw new Error("Panic! " + msg);
+}
+
+export {
+  $$EvalError,
+  $$RangeError,
+  $$ReferenceError,
+  $$SyntaxError,
+  $$TypeError,
+  $$URIError,
+  panic,
+}
+/* No side effect */
diff --git a/lib/es6/Js_exn.js b/lib/es6/Exn.js
similarity index 100%
rename from lib/es6/Js_exn.js
rename to lib/es6/Exn.js
diff --git a/lib/es6/Float.js b/lib/es6/Float.js
new file mode 100644
index 0000000000..d0955e3ce0
--- /dev/null
+++ b/lib/es6/Float.js
@@ -0,0 +1,29 @@
+
+
+
+let Constants = {};
+
+function fromString(i) {
+  let i$1 = parseFloat(i);
+  if (isNaN(i$1)) {
+    return;
+  } else {
+    return i$1;
+  }
+}
+
+function clamp(min, max, value) {
+  let value$1 = max !== undefined && max < value ? max : value;
+  if (min !== undefined && min > value$1) {
+    return min;
+  } else {
+    return value$1;
+  }
+}
+
+export {
+  Constants,
+  fromString,
+  clamp,
+}
+/* No side effect */
diff --git a/lib/es6/Float32Array.js b/lib/es6/Float32Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/Float32Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/Float64Array.js b/lib/es6/Float64Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/Float64Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/Hashtbl.js b/lib/es6/Hashtbl.js
deleted file mode 100644
index c95915f5b8..0000000000
--- a/lib/es6/Hashtbl.js
+++ /dev/null
@@ -1,12 +0,0 @@
-
-
-import * as Primitive_hash from "./Primitive_hash.js";
-
-function hash(x) {
-  return Primitive_hash.hash(10, 100, 0, x);
-}
-
-export {
-  hash,
-}
-/* No side effect */
diff --git a/lib/es6/Int.js b/lib/es6/Int.js
new file mode 100644
index 0000000000..d817901429
--- /dev/null
+++ b/lib/es6/Int.js
@@ -0,0 +1,86 @@
+
+
+import * as $$Array from "./Array.js";
+
+function fromString(x, radix) {
+  let maybeInt = radix !== undefined ? parseInt(x, radix) : parseInt(x);
+  if (isNaN(maybeInt) || maybeInt > 2147483647 || maybeInt < -2147483648) {
+    return;
+  } else {
+    return maybeInt | 0;
+  }
+}
+
+function abs(x) {
+  if (x >= 0) {
+    return x;
+  } else {
+    return -x | 0;
+  }
+}
+
+function range(start, end, optionsOpt) {
+  let options = optionsOpt !== undefined ? optionsOpt : ({});
+  let isInverted = start > end;
+  let n = options.step;
+  let step;
+  if (n !== undefined) {
+    if (n !== 0) {
+      step = n;
+    } else {
+      if (start !== end) {
+        throw new RangeError("Incorrect range arguments");
+      }
+      step = n;
+    }
+  } else {
+    step = isInverted ? -1 : 1;
+  }
+  let length;
+  if (isInverted === step >= 0) {
+    length = 0;
+  } else if (step === 0) {
+    length = options.inclusive === true ? 1 : 0;
+  } else {
+    let range$1 = isInverted ? start - end | 0 : end - start | 0;
+    let range$2 = options.inclusive === true ? range$1 + 1 | 0 : range$1;
+    length = Math.ceil(range$2 / abs(step)) | 0;
+  }
+  return $$Array.fromInitializer(length, i => start + Math.imul(i, step) | 0);
+}
+
+function rangeWithOptions(start, end, options) {
+  return range(start, end, options);
+}
+
+function clamp(min, max, value) {
+  let value$1 = max !== undefined && max < value ? max : value;
+  if (min !== undefined && min > value$1) {
+    return min;
+  } else {
+    return value$1;
+  }
+}
+
+function lnot(x) {
+  return x ^ -1;
+}
+
+let Bitwise = {
+  lnot: lnot
+};
+
+let Constants = {
+  minValue: -2147483648,
+  maxValue: 2147483647
+};
+
+export {
+  Constants,
+  fromString,
+  range,
+  rangeWithOptions,
+  clamp,
+  Bitwise,
+}
+/* No side effect */
diff --git a/lib/es6/Int16Array.js b/lib/es6/Int16Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/Int16Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/Int32Array.js b/lib/es6/Int32Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/Int32Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/Int8Array.js b/lib/es6/Int8Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/Int8Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/Intl.js b/lib/es6/Intl.js
new file mode 100644
index 0000000000..17f2e18e06
--- /dev/null
+++ b/lib/es6/Intl.js
@@ -0,0 +1,36 @@
+
+
+
+let Common;
+
+let Collator;
+
+let DateTimeFormat;
+
+let ListFormat;
+
+let Locale;
+
+let NumberFormat;
+
+let PluralRules;
+
+let RelativeTimeFormat;
+
+let Segmenter;
+
+let Segments;
+
+export {
+  Common,
+  Collator,
+  DateTimeFormat,
+  ListFormat,
+  Locale,
+  NumberFormat,
+  PluralRules,
+  RelativeTimeFormat,
+  Segmenter,
+  Segments,
+}
+/* No side effect */
diff --git a/lib/es6/Intl_Collator.js b/lib/es6/Intl_Collator.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Intl_Collator.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Intl_Common.js b/lib/es6/Intl_Common.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Intl_Common.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Intl_DateTimeFormat.js b/lib/es6/Intl_DateTimeFormat.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Intl_DateTimeFormat.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Intl_ListFormat.js b/lib/es6/Intl_ListFormat.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Intl_ListFormat.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Intl_Locale.js b/lib/es6/Intl_Locale.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Intl_Locale.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Intl_NumberFormat.js b/lib/es6/Intl_NumberFormat.js
new file mode 100644
index 0000000000..4b29a9b669
--- /dev/null
+++ b/lib/es6/Intl_NumberFormat.js
@@ -0,0 +1,9 @@
+
+
+
+let Grouping;
+
+export {
+  Grouping,
+}
+/* No side effect */
diff --git a/lib/es6/Intl_NumberFormat_Grouping.js b/lib/es6/Intl_NumberFormat_Grouping.js
new file mode 100644
index 0000000000..4633bbc588
--- /dev/null
+++ b/lib/es6/Intl_NumberFormat_Grouping.js
@@ -0,0 +1,35 @@
+
+
+import * as Type from "./Type.js";
+
+function parseJsValue(value) {
+  let value$1 = Type.Classify.classify(value);
+  if (typeof value$1 !== "object") {
+    return;
+  }
+  switch (value$1.TAG) {
+    case "Bool" :
+      return {
+        NAME: "bool",
+        VAL: value$1._0
+      };
+    case "String" :
+      switch (value$1._0) {
+        case "always" :
+          return "always";
+        case "auto" :
+          return "auto";
+        case "min2" :
+          return "min2";
+        default:
+          return;
+      }
+    default:
+      return;
+  }
+}
+
+export {
+  parseJsValue,
+}
+/* No side effect */
diff --git a/lib/es6/Intl_PluralRules.js b/lib/es6/Intl_PluralRules.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Intl_PluralRules.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Intl_RelativeTimeFormat.js b/lib/es6/Intl_RelativeTimeFormat.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Intl_RelativeTimeFormat.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Intl_Segmenter.js b/lib/es6/Intl_Segmenter.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Intl_Segmenter.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Intl_Segments.js b/lib/es6/Intl_Segments.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Intl_Segments.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Iterator.js b/lib/es6/Iterator.js
new file mode 100644
index 0000000000..e793b51c42
--- /dev/null
+++ b/lib/es6/Iterator.js
@@ -0,0 +1,16 @@
+
+
+
+function forEach(iterator, f) {
+  let iteratorDone = false;
+  while (!iteratorDone) {
+    let match = iterator.next();
+    f(match.value);
+    iteratorDone = match.done;
+  };
+}
+
+export {
+  forEach,
+}
+/* No side effect */
diff --git a/lib/es6/JSON.js b/lib/es6/JSON.js
new file mode 100644
index 0000000000..e547968d71
--- /dev/null
+++ b/lib/es6/JSON.js
@@ -0,0 +1,100 @@
+
+
+import * as Primitive_option from "./Primitive_option.js";
+
+function classify(value) {
+  let match = Object.prototype.toString.call(value);
+  switch (match) {
+    case "[object Array]" :
+      return {
+        TAG: "Array",
+        _0: value
+      };
+    case "[object Boolean]" :
+      return {
+        TAG: "Bool",
+        _0: value
+      };
+    case "[object Null]" :
+      return "Null";
+    case "[object Number]" :
+      return {
+        TAG: "Number",
+        _0: value
+      };
+    case "[object String]" :
+      return {
+        TAG: "String",
+        _0: value
+      };
+    default:
+      return {
+        TAG: "Object",
+        _0: value
+      };
+  }
+}
+
+let Classify = {
+  classify: classify
+};
+
+let Encode = {};
+
+function bool(json) {
+  if (typeof json === "boolean") {
+    return json;
+  }
+  
+}
+
+function $$null(json) {
+  if (json === undefined) {
+    return Primitive_option.some(undefined);
+  }
+  
+}
+
+function string(json) {
+  if (typeof json === "string") {
+    return json;
+  }
+  
+}
+
+function float(json) {
+  if (typeof json === "number") {
+    return json;
+  }
+  
+}
+
+function object(json) {
+  if (typeof json === "object" && !Array.isArray(json) && json !== undefined) {
+    return json;
+  }
+  
+}
+
+function array(json) {
+  if (Array.isArray(json)) {
+    return json;
+  }
+  
+}
+
+let Decode = {
+  bool: bool,
+  $$null: $$null,
+  string: string,
+  float: float,
+  object: object,
+  array: array
+};
+
+export {
+  Classify,
+  Encode,
+  Decode,
+}
+/* No side effect */
diff --git a/lib/es6/List.js b/lib/es6/List.js
index dbde576692..89b2209010 100644
--- a/lib/es6/List.js
+++ b/lib/es6/List.js
@@ -1,1606 +1,957 @@
 
 
-import * as Pervasives from "./Pervasives.js";
+import * as $$Array from "./Array.js";
+import * as Primitive_int from "./Primitive_int.js";
 import * as Primitive_option from "./Primitive_option.js";
 
-function length(l) {
-  let _len = 0;
-  let _param = l;
-  while (true) {
-    let param = _param;
-    let len = _len;
-    if (!param) {
-      return len;
-    }
-    _param = param.tl;
-    _len = len + 1 | 0;
-    continue;
-  };
-}
-
-function cons(a, l) {
-  return {
-    hd: a,
-    tl: l
-  };
+function head(x) {
+  if (x) {
+    return Primitive_option.some(x.hd);
+  }
+  
 }
 
-function hd(param) {
-  if (param) {
-    return param.hd;
+function headExn(x) {
+  if (x) {
+    return x.hd;
   }
   throw {
-    RE_EXN_ID: "Failure",
-    _1: "hd",
+    RE_EXN_ID: "Not_found",
     Error: new Error()
   };
 }
 
-function tl(param) {
-  if (param) {
-    return param.tl;
+function tail(x) {
+  if (x) {
+    return x.tl;
+  }
+  
+}
+
+function tailExn(x) {
+  if (x) {
+    return x.tl;
   }
   throw {
-    RE_EXN_ID: "Failure",
-    _1: "tl",
+    RE_EXN_ID: "Not_found",
     Error: new Error()
   };
 }
 
-function nth(l, n) {
+function add(xs, x) {
+  return {
+    hd: x,
+    tl: xs
+  };
+}
+
+function get(x, n) {
+  if (n < 0) {
+    return;
+  } else {
+    let _x = x;
+    let _n = n;
+    while (true) {
+      let n$1 = _n;
+      let x$1 = _x;
+      if (!x$1) {
+        return;
+      }
+      if (n$1 === 0) {
+        return Primitive_option.some(x$1.hd);
+      }
+      _n = n$1 - 1 | 0;
+      _x = x$1.tl;
+      continue;
+    };
+  }
+}
+
+function getExn(x, n) {
   if (n < 0) {
     throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.nth",
+      RE_EXN_ID: "Not_found",
       Error: new Error()
     };
   }
-  let _l = l;
+  let _x = x;
   let _n = n;
   while (true) {
     let n$1 = _n;
-    let l$1 = _l;
-    if (l$1) {
+    let x$1 = _x;
+    if (x$1) {
       if (n$1 === 0) {
-        return l$1.hd;
+        return x$1.hd;
       }
       _n = n$1 - 1 | 0;
-      _l = l$1.tl;
+      _x = x$1.tl;
       continue;
     }
     throw {
-      RE_EXN_ID: "Failure",
-      _1: "nth",
+      RE_EXN_ID: "Not_found",
       Error: new Error()
     };
   };
 }
 
-function nth_opt(l, n) {
-  if (n < 0) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.nth",
-      Error: new Error()
-    };
-  }
-  let _l = l;
-  let _n = n;
+function partitionAux(p, _cell, _precX, _precY) {
   while (true) {
-    let n$1 = _n;
-    let l$1 = _l;
-    if (!l$1) {
+    let precY = _precY;
+    let precX = _precX;
+    let cell = _cell;
+    if (!cell) {
       return;
     }
-    if (n$1 === 0) {
-      return Primitive_option.some(l$1.hd);
+    let t = cell.tl;
+    let h = cell.hd;
+    let next = {
+      hd: h,
+      tl: /* [] */0
+    };
+    if (p(h)) {
+      precX.tl = next;
+      _precX = next;
+      _cell = t;
+      continue;
     }
-    _n = n$1 - 1 | 0;
-    _l = l$1.tl;
+    precY.tl = next;
+    _precY = next;
+    _cell = t;
     continue;
   };
 }
 
-function rev_append(_l1, _l2) {
+function splitAux(_cell, _precX, _precY) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    if (!l1) {
-      return l2;
+    let precY = _precY;
+    let precX = _precX;
+    let cell = _cell;
+    if (!cell) {
+      return;
     }
-    _l2 = {
-      hd: l1.hd,
-      tl: l2
+    let match = cell.hd;
+    let nextA = {
+      hd: match[0],
+      tl: /* [] */0
     };
-    _l1 = l1.tl;
-    continue;
-  };
-}
-
-function rev(l) {
-  return rev_append(l, /* [] */0);
-}
-
-function init_tailrec_aux(_acc, _i, n, f) {
-  while (true) {
-    let i = _i;
-    let acc = _acc;
-    if (i >= n) {
-      return acc;
-    }
-    _i = i + 1 | 0;
-    _acc = {
-      hd: f(i),
-      tl: acc
+    let nextB = {
+      hd: match[1],
+      tl: /* [] */0
     };
+    precX.tl = nextA;
+    precY.tl = nextB;
+    _precY = nextB;
+    _precX = nextA;
+    _cell = cell.tl;
     continue;
   };
 }
 
-function init_aux(i, n, f) {
-  if (i >= n) {
-    return /* [] */0;
-  }
-  let r = f(i);
-  return {
-    hd: r,
-    tl: init_aux(i + 1 | 0, n, f)
-  };
-}
-
-function init(len, f) {
-  if (len < 0) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.init",
-      Error: new Error()
-    };
-  }
-  if (len > 10000) {
-    return rev_append(init_tailrec_aux(/* [] */0, 0, len, f), /* [] */0);
-  } else {
-    return init_aux(0, len, f);
-  }
-}
-
-function flatten(param) {
-  if (param) {
-    return Pervasives.$at(param.hd, flatten(param.tl));
-  } else {
-    return /* [] */0;
-  }
-}
-
-function map(f, param) {
-  if (!param) {
-    return /* [] */0;
-  }
-  let r = f(param.hd);
-  return {
-    hd: r,
-    tl: map(f, param.tl)
-  };
-}
-
-function mapi(i, f, param) {
-  if (!param) {
-    return /* [] */0;
-  }
-  let r = f(i, param.hd);
-  return {
-    hd: r,
-    tl: mapi(i + 1 | 0, f, param.tl)
-  };
-}
-
-function mapi$1(f, l) {
-  return mapi(0, f, l);
-}
-
-function rev_map(f, l) {
-  let _accu = /* [] */0;
-  let _param = l;
+function copyAuxCont(_cellX, _prec) {
   while (true) {
-    let param = _param;
-    let accu = _accu;
-    if (!param) {
-      return accu;
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
+      return prec;
     }
-    _param = param.tl;
-    _accu = {
-      hd: f(param.hd),
-      tl: accu
+    let next = {
+      hd: cellX.hd,
+      tl: /* [] */0
     };
+    prec.tl = next;
+    _prec = next;
+    _cellX = cellX.tl;
     continue;
   };
 }
 
-function iter(f, _param) {
+function copyAuxWitFilter(f, _cellX, _prec) {
   while (true) {
-    let param = _param;
-    if (!param) {
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
       return;
     }
-    f(param.hd);
-    _param = param.tl;
+    let t = cellX.tl;
+    let h = cellX.hd;
+    if (f(h)) {
+      let next = {
+        hd: h,
+        tl: /* [] */0
+      };
+      prec.tl = next;
+      _prec = next;
+      _cellX = t;
+      continue;
+    }
+    _cellX = t;
     continue;
   };
 }
 
-function iteri(f, l) {
-  let _i = 0;
-  let _param = l;
+function copyAuxWithFilterIndex(f, _cellX, _prec, _i) {
   while (true) {
-    let param = _param;
     let i = _i;
-    if (!param) {
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
       return;
     }
-    f(i, param.hd);
-    _param = param.tl;
+    let t = cellX.tl;
+    let h = cellX.hd;
+    if (f(h, i)) {
+      let next = {
+        hd: h,
+        tl: /* [] */0
+      };
+      prec.tl = next;
+      _i = i + 1 | 0;
+      _prec = next;
+      _cellX = t;
+      continue;
+    }
     _i = i + 1 | 0;
+    _cellX = t;
     continue;
   };
 }
 
-function fold_left(f, _accu, _l) {
+function copyAuxWitFilterMap(f, _cellX, _prec) {
   while (true) {
-    let l = _l;
-    let accu = _accu;
-    if (!l) {
-      return accu;
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
+      return;
     }
-    _l = l.tl;
-    _accu = f(accu, l.hd);
+    let t = cellX.tl;
+    let h = f(cellX.hd);
+    if (h !== undefined) {
+      let next = {
+        hd: Primitive_option.valFromOption(h),
+        tl: /* [] */0
+      };
+      prec.tl = next;
+      _prec = next;
+      _cellX = t;
+      continue;
+    }
+    _cellX = t;
     continue;
   };
 }
 
-function fold_right(f, l, accu) {
-  if (l) {
-    return f(l.hd, fold_right(f, l.tl, accu));
-  } else {
-    return accu;
-  }
-}
-
-function map2(f, l1, l2) {
-  if (l1) {
-    if (l2) {
-      let r = f(l1.hd, l2.hd);
-      return {
-        hd: r,
-        tl: map2(f, l1.tl, l2.tl)
-      };
+function removeAssocAuxWithMap(_cellX, x, _prec, f) {
+  while (true) {
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
+      return false;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.map2",
-      Error: new Error()
+    let t = cellX.tl;
+    let h = cellX.hd;
+    if (f(h[0], x)) {
+      prec.tl = t;
+      return true;
+    }
+    let next = {
+      hd: h,
+      tl: /* [] */0
     };
-  }
-  if (!l2) {
-    return /* [] */0;
-  }
-  throw {
-    RE_EXN_ID: "Invalid_argument",
-    _1: "List.map2",
-    Error: new Error()
+    prec.tl = next;
+    _prec = next;
+    _cellX = t;
+    continue;
   };
 }
 
-function rev_map2(f, l1, l2) {
-  let _accu = /* [] */0;
-  let _l1 = l1;
-  let _l2 = l2;
+function setAssocAuxWithMap(_cellX, x, k, _prec, eq) {
   while (true) {
-    let l2$1 = _l2;
-    let l1$1 = _l1;
-    let accu = _accu;
-    if (l1$1) {
-      if (l2$1) {
-        _l2 = l2$1.tl;
-        _l1 = l1$1.tl;
-        _accu = {
-          hd: f(l1$1.hd, l2$1.hd),
-          tl: accu
-        };
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.rev_map2",
-        Error: new Error()
-      };
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
+      return false;
     }
-    if (l2$1) {
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.rev_map2",
-        Error: new Error()
+    let t = cellX.tl;
+    let h = cellX.hd;
+    if (eq(h[0], x)) {
+      prec.tl = {
+        hd: [
+          x,
+          k
+        ],
+        tl: t
       };
+      return true;
     }
-    return accu;
+    let next = {
+      hd: h,
+      tl: /* [] */0
+    };
+    prec.tl = next;
+    _prec = next;
+    _cellX = t;
+    continue;
   };
 }
 
-function iter2(f, _l1, _l2) {
+function copyAuxWithMap(_cellX, _prec, f) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    if (l1) {
-      if (l2) {
-        f(l1.hd, l2.hd);
-        _l2 = l2.tl;
-        _l1 = l1.tl;
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.iter2",
-        Error: new Error()
-      };
-    }
-    if (!l2) {
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
       return;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.iter2",
-      Error: new Error()
+    let next = {
+      hd: f(cellX.hd),
+      tl: /* [] */0
     };
+    prec.tl = next;
+    _prec = next;
+    _cellX = cellX.tl;
+    continue;
   };
 }
 
-function fold_left2(f, _accu, _l1, _l2) {
+function zipAux(_cellX, _cellY, _prec) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    let accu = _accu;
-    if (l1) {
-      if (l2) {
-        _l2 = l2.tl;
-        _l1 = l1.tl;
-        _accu = f(accu, l1.hd, l2.hd);
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_left2",
-        Error: new Error()
-      };
-    }
-    if (l2) {
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_left2",
-        Error: new Error()
-      };
+    let prec = _prec;
+    let cellY = _cellY;
+    let cellX = _cellX;
+    if (!cellX) {
+      return;
     }
-    return accu;
-  };
-}
-
-function fold_right2(f, l1, l2, accu) {
-  if (l1) {
-    if (l2) {
-      return f(l1.hd, l2.hd, fold_right2(f, l1.tl, l2.tl, accu));
+    if (!cellY) {
+      return;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.fold_right2",
-      Error: new Error()
-    };
-  }
-  if (l2) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.fold_right2",
-      Error: new Error()
+    let next = {
+      hd: [
+        cellX.hd,
+        cellY.hd
+      ],
+      tl: /* [] */0
     };
-  }
-  return accu;
-}
-
-function for_all(p, _param) {
-  while (true) {
-    let param = _param;
-    if (!param) {
-      return true;
-    }
-    if (!p(param.hd)) {
-      return false;
-    }
-    _param = param.tl;
+    prec.tl = next;
+    _prec = next;
+    _cellY = cellY.tl;
+    _cellX = cellX.tl;
     continue;
   };
 }
 
-function exists(p, _param) {
+function copyAuxWithMap2(f, _cellX, _cellY, _prec) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
+    let prec = _prec;
+    let cellY = _cellY;
+    let cellX = _cellX;
+    if (!cellX) {
+      return;
     }
-    if (p(param.hd)) {
-      return true;
+    if (!cellY) {
+      return;
     }
-    _param = param.tl;
+    let next = {
+      hd: f(cellX.hd, cellY.hd),
+      tl: /* [] */0
+    };
+    prec.tl = next;
+    _prec = next;
+    _cellY = cellY.tl;
+    _cellX = cellX.tl;
     continue;
   };
 }
 
-function for_all2(p, _l1, _l2) {
+function copyAuxWithMapI(f, _i, _cellX, _prec) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    if (l1) {
-      if (l2) {
-        if (!p(l1.hd, l2.hd)) {
-          return false;
-        }
-        _l2 = l2.tl;
-        _l1 = l1.tl;
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.for_all2",
-        Error: new Error()
-      };
-    }
-    if (!l2) {
-      return true;
+    let prec = _prec;
+    let cellX = _cellX;
+    let i = _i;
+    if (!cellX) {
+      return;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.for_all2",
-      Error: new Error()
+    let next = {
+      hd: f(cellX.hd, i),
+      tl: /* [] */0
     };
+    prec.tl = next;
+    _prec = next;
+    _cellX = cellX.tl;
+    _i = i + 1 | 0;
+    continue;
   };
 }
 
-function exists2(p, _l1, _l2) {
+function takeAux(_n, _cell, _prec) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    if (l1) {
-      if (l2) {
-        if (p(l1.hd, l2.hd)) {
-          return true;
-        }
-        _l2 = l2.tl;
-        _l1 = l1.tl;
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.exists2",
-        Error: new Error()
-      };
+    let prec = _prec;
+    let cell = _cell;
+    let n = _n;
+    if (n === 0) {
+      return true;
     }
-    if (!l2) {
+    if (!cell) {
       return false;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.exists2",
-      Error: new Error()
+    let cell$1 = {
+      hd: cell.hd,
+      tl: /* [] */0
     };
+    prec.tl = cell$1;
+    _prec = cell$1;
+    _cell = cell.tl;
+    _n = n - 1 | 0;
+    continue;
   };
 }
 
-function mem(x, _param) {
+function splitAtAux(_n, _cell, _prec) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
+    let prec = _prec;
+    let cell = _cell;
+    let n = _n;
+    if (n === 0) {
+      return cell;
     }
-    if (param.hd === x) {
-      return true;
+    if (!cell) {
+      return;
     }
-    _param = param.tl;
+    let cell$1 = {
+      hd: cell.hd,
+      tl: /* [] */0
+    };
+    prec.tl = cell$1;
+    _prec = cell$1;
+    _cell = cell.tl;
+    _n = n - 1 | 0;
     continue;
   };
 }
 
-function memq(x, _param) {
-  while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
-    }
-    if (param.hd === x) {
-      return true;
-    }
-    _param = param.tl;
-    continue;
+function take(lst, n) {
+  if (n < 0) {
+    return;
+  }
+  if (n === 0) {
+    return /* [] */0;
+  }
+  if (!lst) {
+    return;
+  }
+  let cell = {
+    hd: lst.hd,
+    tl: /* [] */0
   };
+  let has = takeAux(n - 1 | 0, lst.tl, cell);
+  if (has) {
+    return cell;
+  }
+  
 }
 
-function assoc(x, _param) {
-  while (true) {
-    let param = _param;
-    if (param) {
-      let match = param.hd;
-      if (match[0] === x) {
-        return match[1];
+function drop(lst, n) {
+  if (n < 0) {
+    return;
+  } else {
+    let _l = lst;
+    let _n = n;
+    while (true) {
+      let n$1 = _n;
+      let l = _l;
+      if (n$1 === 0) {
+        return l;
       }
-      _param = param.tl;
+      if (!l) {
+        return;
+      }
+      _n = n$1 - 1 | 0;
+      _l = l.tl;
       continue;
-    }
-    throw {
-      RE_EXN_ID: "Not_found",
-      Error: new Error()
     };
+  }
+}
+
+function splitAt(lst, n) {
+  if (n < 0) {
+    return;
+  }
+  if (n === 0) {
+    return [
+      /* [] */0,
+      lst
+    ];
+  }
+  if (!lst) {
+    return;
+  }
+  let cell = {
+    hd: lst.hd,
+    tl: /* [] */0
   };
+  let rest = splitAtAux(n - 1 | 0, lst.tl, cell);
+  if (rest !== undefined) {
+    return [
+      cell,
+      rest
+    ];
+  }
+  
 }
 
-function assoc_opt(x, _param) {
+function concat(xs, ys) {
+  if (!xs) {
+    return ys;
+  }
+  let cell = {
+    hd: xs.hd,
+    tl: /* [] */0
+  };
+  copyAuxCont(xs.tl, cell).tl = ys;
+  return cell;
+}
+
+function map(xs, f) {
+  if (!xs) {
+    return /* [] */0;
+  }
+  let cell = {
+    hd: f(xs.hd),
+    tl: /* [] */0
+  };
+  copyAuxWithMap(xs.tl, cell, f);
+  return cell;
+}
+
+function zipBy(l1, l2, f) {
+  if (!l1) {
+    return /* [] */0;
+  }
+  if (!l2) {
+    return /* [] */0;
+  }
+  let cell = {
+    hd: f(l1.hd, l2.hd),
+    tl: /* [] */0
+  };
+  copyAuxWithMap2(f, l1.tl, l2.tl, cell);
+  return cell;
+}
+
+function mapWithIndex(xs, f) {
+  if (!xs) {
+    return /* [] */0;
+  }
+  let cell = {
+    hd: f(xs.hd, 0),
+    tl: /* [] */0
+  };
+  copyAuxWithMapI(f, 1, xs.tl, cell);
+  return cell;
+}
+
+function fromInitializer(n, f) {
+  if (n <= 0) {
+    return /* [] */0;
+  }
+  let headX = {
+    hd: f(0),
+    tl: /* [] */0
+  };
+  let cur = headX;
+  let i = 1;
+  while (i < n) {
+    let v = {
+      hd: f(i),
+      tl: /* [] */0
+    };
+    cur.tl = v;
+    cur = v;
+    i = i + 1 | 0;
+  };
+  return headX;
+}
+
+function make(n, v) {
+  if (n <= 0) {
+    return /* [] */0;
+  }
+  let headX = {
+    hd: v,
+    tl: /* [] */0
+  };
+  let cur = headX;
+  let i = 1;
+  while (i < n) {
+    let v$1 = {
+      hd: v,
+      tl: /* [] */0
+    };
+    cur.tl = v$1;
+    cur = v$1;
+    i = i + 1 | 0;
+  };
+  return headX;
+}
+
+function length(xs) {
+  let _x = xs;
+  let _acc = 0;
   while (true) {
-    let param = _param;
-    if (!param) {
-      return;
+    let acc = _acc;
+    let x = _x;
+    if (!x) {
+      return acc;
     }
-    let match = param.hd;
-    if (match[0] === x) {
-      return Primitive_option.some(match[1]);
+    _acc = acc + 1 | 0;
+    _x = x.tl;
+    continue;
+  };
+}
+
+function fillAux(arr, _i, _x) {
+  while (true) {
+    let x = _x;
+    let i = _i;
+    if (!x) {
+      return;
     }
-    _param = param.tl;
+    arr[i] = x.hd;
+    _x = x.tl;
+    _i = i + 1 | 0;
     continue;
   };
 }
 
-function assq(x, _param) {
+function fromArray(a) {
+  let _i = a.length - 1 | 0;
+  let _res = /* [] */0;
   while (true) {
-    let param = _param;
-    if (param) {
-      let match = param.hd;
-      if (match[0] === x) {
-        return match[1];
-      }
-      _param = param.tl;
-      continue;
+    let res = _res;
+    let i = _i;
+    if (i < 0) {
+      return res;
     }
-    throw {
-      RE_EXN_ID: "Not_found",
-      Error: new Error()
+    _res = {
+      hd: a[i],
+      tl: res
     };
+    _i = i - 1 | 0;
+    continue;
   };
 }
 
-function assq_opt(x, _param) {
+function toArray(x) {
+  let len = length(x);
+  let arr = new Array(len);
+  fillAux(arr, 0, x);
+  return arr;
+}
+
+function toShuffled(xs) {
+  let v = toArray(xs);
+  $$Array.shuffle(v);
+  return fromArray(v);
+}
+
+function reverseConcat(_l1, _l2) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return;
-    }
-    let match = param.hd;
-    if (match[0] === x) {
-      return Primitive_option.some(match[1]);
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return l2;
     }
-    _param = param.tl;
+    _l2 = {
+      hd: l1.hd,
+      tl: l2
+    };
+    _l1 = l1.tl;
     continue;
   };
 }
 
-function mem_assoc(x, _param) {
+function reverse(l) {
+  return reverseConcat(l, /* [] */0);
+}
+
+function flatAux(_prec, _xs) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
-    }
-    if (param.hd[0] === x) {
-      return true;
+    let xs = _xs;
+    let prec = _prec;
+    if (xs) {
+      _xs = xs.tl;
+      _prec = copyAuxCont(xs.hd, prec);
+      continue;
     }
-    _param = param.tl;
-    continue;
+    prec.tl = /* [] */0;
+    return;
   };
 }
 
-function mem_assq(x, _param) {
+function flat(_xs) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
+    let xs = _xs;
+    if (!xs) {
+      return /* [] */0;
     }
-    if (param.hd[0] === x) {
-      return true;
+    let match = xs.hd;
+    if (match) {
+      let cell = {
+        hd: match.hd,
+        tl: /* [] */0
+      };
+      flatAux(copyAuxCont(match.tl, cell), xs.tl);
+      return cell;
     }
-    _param = param.tl;
+    _xs = xs.tl;
     continue;
   };
 }
 
-function remove_assoc(x, param) {
-  if (!param) {
-    return /* [] */0;
+function concatMany(xs) {
+  let len = xs.length;
+  if (len === 1) {
+    return xs[0];
   }
-  let l = param.tl;
-  let pair = param.hd;
-  if (pair[0] === x) {
-    return l;
-  } else {
-    return {
-      hd: pair,
-      tl: remove_assoc(x, l)
-    };
-  }
-}
-
-function remove_assq(x, param) {
-  if (!param) {
+  if (len === 0) {
     return /* [] */0;
   }
-  let l = param.tl;
-  let pair = param.hd;
-  if (pair[0] === x) {
-    return l;
-  } else {
-    return {
-      hd: pair,
-      tl: remove_assq(x, l)
-    };
+  let len$1 = xs.length;
+  let v = xs[len$1 - 1 | 0];
+  for (let i = len$1 - 2 | 0; i >= 0; --i) {
+    v = concat(xs[i], v);
   }
+  return v;
 }
 
-function find(p, _param) {
+function mapReverse(l, f) {
+  let _accu = /* [] */0;
+  let _xs = l;
   while (true) {
-    let param = _param;
-    if (param) {
-      let x = param.hd;
-      if (p(x)) {
-        return x;
-      }
-      _param = param.tl;
-      continue;
+    let xs = _xs;
+    let accu = _accu;
+    if (!xs) {
+      return accu;
     }
-    throw {
-      RE_EXN_ID: "Not_found",
-      Error: new Error()
+    _xs = xs.tl;
+    _accu = {
+      hd: f(xs.hd),
+      tl: accu
     };
+    continue;
   };
 }
 
-function find_opt(p, _param) {
+function forEach(_xs, f) {
   while (true) {
-    let param = _param;
-    if (!param) {
+    let xs = _xs;
+    if (!xs) {
       return;
     }
-    let x = param.hd;
-    if (p(x)) {
-      return Primitive_option.some(x);
+    f(xs.hd);
+    _xs = xs.tl;
+    continue;
+  };
+}
+
+function forEachWithIndex(l, f) {
+  let _xs = l;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    let xs = _xs;
+    if (!xs) {
+      return;
     }
-    _param = param.tl;
+    f(xs.hd, i);
+    _i = i + 1 | 0;
+    _xs = xs.tl;
     continue;
   };
 }
 
-function find_all(p, l) {
-  let _accu = /* [] */0;
-  let _param = l;
+function reduce(_l, _accu, f) {
   while (true) {
-    let param = _param;
     let accu = _accu;
-    if (!param) {
-      return rev_append(accu, /* [] */0);
+    let l = _l;
+    if (!l) {
+      return accu;
     }
-    let l$1 = param.tl;
-    let x = param.hd;
-    if (p(x)) {
-      _param = l$1;
-      _accu = {
-        hd: x,
-        tl: accu
-      };
-      continue;
+    _accu = f(accu, l.hd);
+    _l = l.tl;
+    continue;
+  };
+}
+
+function reduceReverseUnsafe(l, accu, f) {
+  if (l) {
+    return f(reduceReverseUnsafe(l.tl, accu, f), l.hd);
+  } else {
+    return accu;
+  }
+}
+
+function reduceReverse(l, acc, f) {
+  let len = length(l);
+  if (len < 1000) {
+    return reduceReverseUnsafe(l, acc, f);
+  } else {
+    let a = toArray(l);
+    let r = acc;
+    for (let i = a.length - 1 | 0; i >= 0; --i) {
+      r = f(r, a[i]);
     }
-    _param = l$1;
+    return r;
+  }
+}
+
+function reduceWithIndex(l, acc, f) {
+  let _l = l;
+  let _acc = acc;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    let acc$1 = _acc;
+    let l$1 = _l;
+    if (!l$1) {
+      return acc$1;
+    }
+    _i = i + 1 | 0;
+    _acc = f(acc$1, l$1.hd, i);
+    _l = l$1.tl;
     continue;
   };
 }
 
-function partition(p, l) {
-  let _yes = /* [] */0;
-  let _no = /* [] */0;
-  let _param = l;
+function mapReverse2(l1, l2, f) {
+  let _l1 = l1;
+  let _l2 = l2;
+  let _accu = /* [] */0;
   while (true) {
-    let param = _param;
-    let no = _no;
-    let yes = _yes;
-    if (!param) {
-      return [
-        rev_append(yes, /* [] */0),
-        rev_append(no, /* [] */0)
-      ];
-    }
-    let l$1 = param.tl;
-    let x = param.hd;
-    if (p(x)) {
-      _param = l$1;
-      _yes = {
-        hd: x,
-        tl: yes
-      };
-      continue;
+    let accu = _accu;
+    let l2$1 = _l2;
+    let l1$1 = _l1;
+    if (!l1$1) {
+      return accu;
     }
-    _param = l$1;
-    _no = {
-      hd: x,
-      tl: no
+    if (!l2$1) {
+      return accu;
+    }
+    _accu = {
+      hd: f(l1$1.hd, l2$1.hd),
+      tl: accu
     };
+    _l2 = l2$1.tl;
+    _l1 = l1$1.tl;
     continue;
   };
 }
 
-function split(param) {
-  if (!param) {
-    return [
-      /* [] */0,
-      /* [] */0
-    ];
-  }
-  let match = param.hd;
-  let match$1 = split(param.tl);
-  return [
-    {
-      hd: match[0],
-      tl: match$1[0]
-    },
-    {
-      hd: match[1],
-      tl: match$1[1]
+function forEach2(_l1, _l2, f) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return;
     }
-  ];
+    if (!l2) {
+      return;
+    }
+    f(l1.hd, l2.hd);
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
 }
 
-function combine(l1, l2) {
-  if (l1) {
-    if (l2) {
-      return {
-        hd: [
-          l1.hd,
-          l2.hd
-        ],
-        tl: combine(l1.tl, l2.tl)
-      };
+function reduce2(_l1, _l2, _accu, f) {
+  while (true) {
+    let accu = _accu;
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return accu;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.combine",
-      Error: new Error()
-    };
-  }
-  if (!l2) {
-    return /* [] */0;
-  }
-  throw {
-    RE_EXN_ID: "Invalid_argument",
-    _1: "List.combine",
-    Error: new Error()
+    if (!l2) {
+      return accu;
+    }
+    _accu = f(accu, l1.hd, l2.hd);
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
   };
 }
 
-function merge(cmp, l1, l2) {
-  if (!l1) {
-    return l2;
-  }
-  if (!l2) {
-    return l1;
+function reduceReverse2Unsafe(l1, l2, accu, f) {
+  if (l1 && l2) {
+    return f(reduceReverse2Unsafe(l1.tl, l2.tl, accu, f), l1.hd, l2.hd);
+  } else {
+    return accu;
   }
-  let h2 = l2.hd;
-  let h1 = l1.hd;
-  if (cmp(h1, h2) <= 0) {
-    return {
-      hd: h1,
-      tl: merge(cmp, l1.tl, l2)
-    };
+}
+
+function reduceReverse2(l1, l2, acc, f) {
+  let len = length(l1);
+  if (len < 1000) {
+    return reduceReverse2Unsafe(l1, l2, acc, f);
   } else {
-    return {
-      hd: h2,
-      tl: merge(cmp, l1, l2.tl)
-    };
+    let a = toArray(l1);
+    let b = toArray(l2);
+    let r = acc;
+    let len$1 = Primitive_int.max(a.length, b.length);
+    for (let i = len$1 - 1 | 0; i >= 0; --i) {
+      r = f(r, a[i], b[i]);
+    }
+    return r;
   }
 }
 
-function chop(_k, _l) {
+function every(_xs, p) {
   while (true) {
-    let l = _l;
-    let k = _k;
-    if (k === 0) {
-      return l;
+    let xs = _xs;
+    if (!xs) {
+      return true;
     }
-    if (l) {
-      _l = l.tl;
-      _k = k - 1 | 0;
-      continue;
+    if (!p(xs.hd)) {
+      return false;
     }
-    throw {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "List.res",
-        411,
-        11
-      ],
-      Error: new Error()
-    };
+    _xs = xs.tl;
+    continue;
   };
 }
 
-function stable_sort(cmp, l) {
-  let sort = (n, l) => {
-    if (n !== 2) {
-      if (n === 3 && l) {
-        let match = l.tl;
-        if (match) {
-          let match$1 = match.tl;
-          if (match$1) {
-            let x3 = match$1.hd;
-            let x2 = match.hd;
-            let x1 = l.hd;
-            if (cmp(x1, x2) <= 0) {
-              if (cmp(x2, x3) <= 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: {
-                      hd: x3,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else if (cmp(x1, x3) <= 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-            } else if (cmp(x1, x3) <= 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else if (cmp(x2, x3) <= 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else {
-              return {
-                hd: x3,
-                tl: {
-                  hd: x2,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-          }
-          
-        }
-        
-      }
-      
-    } else if (l) {
-      let match$2 = l.tl;
-      if (match$2) {
-        let x2$1 = match$2.hd;
-        let x1$1 = l.hd;
-        if (cmp(x1$1, x2$1) <= 0) {
-          return {
-            hd: x1$1,
-            tl: {
-              hd: x2$1,
-              tl: /* [] */0
-            }
-          };
-        } else {
-          return {
-            hd: x2$1,
-            tl: {
-              hd: x1$1,
-              tl: /* [] */0
-            }
-          };
-        }
-      }
-      
-    }
-    let n1 = (n >> 1);
-    let n2 = n - n1 | 0;
-    let l2 = chop(n1, l);
-    let s1 = rev_sort(n1, l);
-    let s2 = rev_sort(n2, l2);
-    let _l1 = s1;
-    let _l2 = s2;
-    let _accu = /* [] */0;
-    while (true) {
-      let accu = _accu;
-      let l2$1 = _l2;
-      let l1 = _l1;
-      if (!l1) {
-        return rev_append(l2$1, accu);
-      }
-      if (!l2$1) {
-        return rev_append(l1, accu);
-      }
-      let h2 = l2$1.hd;
-      let h1 = l1.hd;
-      if (cmp(h1, h2) > 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l1 = l1.tl;
-        continue;
-      }
-      _accu = {
-        hd: h2,
-        tl: accu
-      };
-      _l2 = l2$1.tl;
-      continue;
-    };
-  };
-  let rev_sort = (n, l) => {
-    if (n !== 2) {
-      if (n === 3 && l) {
-        let match = l.tl;
-        if (match) {
-          let match$1 = match.tl;
-          if (match$1) {
-            let x3 = match$1.hd;
-            let x2 = match.hd;
-            let x1 = l.hd;
-            if (cmp(x1, x2) > 0) {
-              if (cmp(x2, x3) > 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: {
-                      hd: x3,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else if (cmp(x1, x3) > 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-            } else if (cmp(x1, x3) > 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else if (cmp(x2, x3) > 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else {
-              return {
-                hd: x3,
-                tl: {
-                  hd: x2,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-          }
-          
-        }
-        
-      }
-      
-    } else if (l) {
-      let match$2 = l.tl;
-      if (match$2) {
-        let x2$1 = match$2.hd;
-        let x1$1 = l.hd;
-        if (cmp(x1$1, x2$1) > 0) {
-          return {
-            hd: x1$1,
-            tl: {
-              hd: x2$1,
-              tl: /* [] */0
-            }
-          };
-        } else {
-          return {
-            hd: x2$1,
-            tl: {
-              hd: x1$1,
-              tl: /* [] */0
-            }
-          };
-        }
-      }
-      
-    }
-    let n1 = (n >> 1);
-    let n2 = n - n1 | 0;
-    let l2 = chop(n1, l);
-    let s1 = sort(n1, l);
-    let s2 = sort(n2, l2);
-    let _l1 = s1;
-    let _l2 = s2;
-    let _accu = /* [] */0;
-    while (true) {
-      let accu = _accu;
-      let l2$1 = _l2;
-      let l1 = _l1;
-      if (!l1) {
-        return rev_append(l2$1, accu);
-      }
-      if (!l2$1) {
-        return rev_append(l1, accu);
-      }
-      let h2 = l2$1.hd;
-      let h1 = l1.hd;
-      if (cmp(h1, h2) <= 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l1 = l1.tl;
-        continue;
-      }
-      _accu = {
-        hd: h2,
-        tl: accu
-      };
-      _l2 = l2$1.tl;
-      continue;
-    };
+function some(_xs, p) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return false;
+    }
+    if (p(xs.hd)) {
+      return true;
+    }
+    _xs = xs.tl;
+    continue;
   };
-  let len = length(l);
-  if (len < 2) {
-    return l;
-  } else {
-    return sort(len, l);
-  }
 }
 
-function sort_uniq(cmp, l) {
-  let sort = (n, l) => {
-    if (n !== 2) {
-      if (n === 3 && l) {
-        let match = l.tl;
-        if (match) {
-          let match$1 = match.tl;
-          if (match$1) {
-            let x3 = match$1.hd;
-            let x2 = match.hd;
-            let x1 = l.hd;
-            let c = cmp(x1, x2);
-            if (c === 0) {
-              let c$1 = cmp(x2, x3);
-              if (c$1 === 0) {
-                return {
-                  hd: x2,
-                  tl: /* [] */0
-                };
-              } else if (c$1 < 0) {
-                return {
-                  hd: x2,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              }
-            }
-            if (c < 0) {
-              let c$2 = cmp(x2, x3);
-              if (c$2 === 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              }
-              if (c$2 < 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: {
-                      hd: x3,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-              let c$3 = cmp(x1, x3);
-              if (c$3 === 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              } else if (c$3 < 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-            }
-            let c$4 = cmp(x1, x3);
-            if (c$4 === 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: /* [] */0
-                }
-              };
-            }
-            if (c$4 < 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-            let c$5 = cmp(x2, x3);
-            if (c$5 === 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: /* [] */0
-                }
-              };
-            } else if (c$5 < 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else {
-              return {
-                hd: x3,
-                tl: {
-                  hd: x2,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-          }
-          
-        }
-        
-      }
-      
-    } else if (l) {
-      let match$2 = l.tl;
-      if (match$2) {
-        let x2$1 = match$2.hd;
-        let x1$1 = l.hd;
-        let c$6 = cmp(x1$1, x2$1);
-        if (c$6 === 0) {
-          return {
-            hd: x1$1,
-            tl: /* [] */0
-          };
-        } else if (c$6 < 0) {
-          return {
-            hd: x1$1,
-            tl: {
-              hd: x2$1,
-              tl: /* [] */0
-            }
-          };
-        } else {
-          return {
-            hd: x2$1,
-            tl: {
-              hd: x1$1,
-              tl: /* [] */0
-            }
-          };
-        }
-      }
-      
-    }
-    let n1 = (n >> 1);
-    let n2 = n - n1 | 0;
-    let l2 = chop(n1, l);
-    let s1 = rev_sort(n1, l);
-    let s2 = rev_sort(n2, l2);
-    let _l1 = s1;
-    let _l2 = s2;
-    let _accu = /* [] */0;
-    while (true) {
-      let accu = _accu;
-      let l2$1 = _l2;
-      let l1 = _l1;
-      if (!l1) {
-        return rev_append(l2$1, accu);
-      }
-      if (!l2$1) {
-        return rev_append(l1, accu);
-      }
-      let t2 = l2$1.tl;
-      let h2 = l2$1.hd;
-      let t1 = l1.tl;
-      let h1 = l1.hd;
-      let c$7 = cmp(h1, h2);
-      if (c$7 === 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l2 = t2;
-        _l1 = t1;
-        continue;
-      }
-      if (c$7 > 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l1 = t1;
-        continue;
-      }
-      _accu = {
-        hd: h2,
-        tl: accu
-      };
-      _l2 = t2;
-      continue;
-    };
-  };
-  let rev_sort = (n, l) => {
-    if (n !== 2) {
-      if (n === 3 && l) {
-        let match = l.tl;
-        if (match) {
-          let match$1 = match.tl;
-          if (match$1) {
-            let x3 = match$1.hd;
-            let x2 = match.hd;
-            let x1 = l.hd;
-            let c = cmp(x1, x2);
-            if (c === 0) {
-              let c$1 = cmp(x2, x3);
-              if (c$1 === 0) {
-                return {
-                  hd: x2,
-                  tl: /* [] */0
-                };
-              } else if (c$1 > 0) {
-                return {
-                  hd: x2,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              }
-            }
-            if (c > 0) {
-              let c$2 = cmp(x2, x3);
-              if (c$2 === 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              }
-              if (c$2 > 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: {
-                      hd: x3,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-              let c$3 = cmp(x1, x3);
-              if (c$3 === 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              } else if (c$3 > 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-            }
-            let c$4 = cmp(x1, x3);
-            if (c$4 === 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: /* [] */0
-                }
-              };
-            }
-            if (c$4 > 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-            let c$5 = cmp(x2, x3);
-            if (c$5 === 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: /* [] */0
-                }
-              };
-            } else if (c$5 > 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else {
-              return {
-                hd: x3,
-                tl: {
-                  hd: x2,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-          }
-          
-        }
-        
-      }
-      
-    } else if (l) {
-      let match$2 = l.tl;
-      if (match$2) {
-        let x2$1 = match$2.hd;
-        let x1$1 = l.hd;
-        let c$6 = cmp(x1$1, x2$1);
-        if (c$6 === 0) {
-          return {
-            hd: x1$1,
-            tl: /* [] */0
-          };
-        } else if (c$6 > 0) {
-          return {
-            hd: x1$1,
-            tl: {
-              hd: x2$1,
-              tl: /* [] */0
-            }
-          };
-        } else {
-          return {
-            hd: x2$1,
-            tl: {
-              hd: x1$1,
-              tl: /* [] */0
-            }
-          };
-        }
-      }
-      
-    }
-    let n1 = (n >> 1);
-    let n2 = n - n1 | 0;
-    let l2 = chop(n1, l);
-    let s1 = sort(n1, l);
-    let s2 = sort(n2, l2);
-    let _l1 = s1;
-    let _l2 = s2;
-    let _accu = /* [] */0;
-    while (true) {
-      let accu = _accu;
-      let l2$1 = _l2;
-      let l1 = _l1;
-      if (!l1) {
-        return rev_append(l2$1, accu);
-      }
-      if (!l2$1) {
-        return rev_append(l1, accu);
-      }
-      let t2 = l2$1.tl;
-      let h2 = l2$1.hd;
-      let t1 = l1.tl;
-      let h1 = l1.hd;
-      let c$7 = cmp(h1, h2);
-      if (c$7 === 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l2 = t2;
-        _l1 = t1;
-        continue;
-      }
-      if (c$7 < 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l1 = t1;
-        continue;
-      }
-      _accu = {
-        hd: h2,
-        tl: accu
-      };
-      _l2 = t2;
-      continue;
-    };
+function every2(_l1, _l2, p) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return true;
+    }
+    if (!l2) {
+      return true;
+    }
+    if (!p(l1.hd, l2.hd)) {
+      return false;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
   };
-  let len = length(l);
-  if (len < 2) {
-    return l;
-  } else {
-    return sort(len, l);
-  }
 }
 
-function compare_lengths(_l1, _l2) {
+function compareLength(_l1, _l2) {
   while (true) {
     let l2 = _l2;
     let l1 = _l1;
@@ -1620,90 +971,392 @@ function compare_lengths(_l1, _l2) {
   };
 }
 
-function compare_length_with(_l, _n) {
+function compare(_l1, _l2, p) {
   while (true) {
-    let n = _n;
-    let l = _l;
-    if (!l) {
-      if (n === 0) {
-        return 0;
-      } else if (n > 0) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      if (l2) {
         return -1;
       } else {
-        return 1;
+        return 0;
       }
     }
-    if (n <= 0) {
+    if (!l2) {
       return 1;
     }
-    _n = n - 1 | 0;
-    _l = l.tl;
+    let c = p(l1.hd, l2.hd);
+    if (c !== 0) {
+      return c;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
+}
+
+function equal(_l1, _l2, p) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      if (l2) {
+        return false;
+      } else {
+        return true;
+      }
+    }
+    if (!l2) {
+      return false;
+    }
+    if (!p(l1.hd, l2.hd)) {
+      return false;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
+}
+
+function some2(_l1, _l2, p) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return false;
+    }
+    if (!l2) {
+      return false;
+    }
+    if (p(l1.hd, l2.hd)) {
+      return true;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
     continue;
   };
 }
 
-let append = Pervasives.$at;
+function has(_xs, x, eq) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return false;
+    }
+    if (eq(xs.hd, x)) {
+      return true;
+    }
+    _xs = xs.tl;
+    continue;
+  };
+}
+
+function getAssoc(_xs, x, eq) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return;
+    }
+    let match = xs.hd;
+    if (eq(match[0], x)) {
+      return Primitive_option.some(match[1]);
+    }
+    _xs = xs.tl;
+    continue;
+  };
+}
+
+function hasAssoc(_xs, x, eq) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return false;
+    }
+    if (eq(xs.hd[0], x)) {
+      return true;
+    }
+    _xs = xs.tl;
+    continue;
+  };
+}
+
+function removeAssoc(xs, x, eq) {
+  if (!xs) {
+    return /* [] */0;
+  }
+  let l = xs.tl;
+  let pair = xs.hd;
+  if (eq(pair[0], x)) {
+    return l;
+  }
+  let cell = {
+    hd: pair,
+    tl: /* [] */0
+  };
+  let removed = removeAssocAuxWithMap(l, x, cell, eq);
+  if (removed) {
+    return cell;
+  } else {
+    return xs;
+  }
+}
+
+function setAssoc(xs, x, k, eq) {
+  if (!xs) {
+    return {
+      hd: [
+        x,
+        k
+      ],
+      tl: /* [] */0
+    };
+  }
+  let l = xs.tl;
+  let pair = xs.hd;
+  if (eq(pair[0], x)) {
+    return {
+      hd: [
+        x,
+        k
+      ],
+      tl: l
+    };
+  }
+  let cell = {
+    hd: pair,
+    tl: /* [] */0
+  };
+  let replaced = setAssocAuxWithMap(l, x, k, cell, eq);
+  if (replaced) {
+    return cell;
+  } else {
+    return {
+      hd: [
+        x,
+        k
+      ],
+      tl: xs
+    };
+  }
+}
+
+function sort(xs, cmp) {
+  let arr = toArray(xs);
+  arr.sort(cmp);
+  return fromArray(arr);
+}
+
+function find(_xs, p) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return;
+    }
+    let x = xs.hd;
+    if (p(x)) {
+      return Primitive_option.some(x);
+    }
+    _xs = xs.tl;
+    continue;
+  };
+}
 
-let concat = flatten;
+function filter(_xs, p) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return /* [] */0;
+    }
+    let t = xs.tl;
+    let h = xs.hd;
+    if (p(h)) {
+      let cell = {
+        hd: h,
+        tl: /* [] */0
+      };
+      copyAuxWitFilter(p, t, cell);
+      return cell;
+    }
+    _xs = t;
+    continue;
+  };
+}
 
-let filter = find_all;
+function filterWithIndex(xs, p) {
+  let _xs = xs;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    let xs$1 = _xs;
+    if (!xs$1) {
+      return /* [] */0;
+    }
+    let t = xs$1.tl;
+    let h = xs$1.hd;
+    if (p(h, i)) {
+      let cell = {
+        hd: h,
+        tl: /* [] */0
+      };
+      copyAuxWithFilterIndex(p, t, cell, i + 1 | 0);
+      return cell;
+    }
+    _i = i + 1 | 0;
+    _xs = t;
+    continue;
+  };
+}
 
-let sort = stable_sort;
+function filterMap(_xs, p) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return /* [] */0;
+    }
+    let t = xs.tl;
+    let h = p(xs.hd);
+    if (h !== undefined) {
+      let cell = {
+        hd: Primitive_option.valFromOption(h),
+        tl: /* [] */0
+      };
+      copyAuxWitFilterMap(p, t, cell);
+      return cell;
+    }
+    _xs = t;
+    continue;
+  };
+}
+
+function partition(l, p) {
+  if (!l) {
+    return [
+      /* [] */0,
+      /* [] */0
+    ];
+  }
+  let h = l.hd;
+  let nextX = {
+    hd: h,
+    tl: /* [] */0
+  };
+  let nextY = {
+    hd: h,
+    tl: /* [] */0
+  };
+  let b = p(h);
+  partitionAux(p, l.tl, nextX, nextY);
+  if (b) {
+    return [
+      nextX,
+      nextY.tl
+    ];
+  } else {
+    return [
+      nextX.tl,
+      nextY
+    ];
+  }
+}
+
+function unzip(xs) {
+  if (!xs) {
+    return [
+      /* [] */0,
+      /* [] */0
+    ];
+  }
+  let match = xs.hd;
+  let cellX = {
+    hd: match[0],
+    tl: /* [] */0
+  };
+  let cellY = {
+    hd: match[1],
+    tl: /* [] */0
+  };
+  splitAux(xs.tl, cellX, cellY);
+  return [
+    cellX,
+    cellY
+  ];
+}
+
+function zip(l1, l2) {
+  if (!l1) {
+    return /* [] */0;
+  }
+  if (!l2) {
+    return /* [] */0;
+  }
+  let cell = {
+    hd: [
+      l1.hd,
+      l2.hd
+    ],
+    tl: /* [] */0
+  };
+  zipAux(l1.tl, l2.tl, cell);
+  return cell;
+}
 
-let fast_sort = stable_sort;
+let size = length;
 
 export {
   length,
-  compare_lengths,
-  compare_length_with,
-  cons,
-  hd,
-  tl,
-  nth,
-  nth_opt,
-  rev,
-  init,
-  append,
-  rev_append,
+  size,
+  head,
+  headExn,
+  tail,
+  tailExn,
+  add,
+  get,
+  getExn,
+  make,
+  fromInitializer,
+  toShuffled,
+  drop,
+  take,
+  splitAt,
   concat,
-  flatten,
-  iter,
-  iteri,
+  concatMany,
+  reverseConcat,
+  flat,
   map,
-  mapi$1 as mapi,
-  rev_map,
-  fold_left,
-  fold_right,
-  iter2,
-  map2,
-  rev_map2,
-  fold_left2,
-  fold_right2,
-  for_all,
-  exists,
-  for_all2,
-  exists2,
-  mem,
-  memq,
+  zip,
+  zipBy,
+  mapWithIndex,
+  fromArray,
+  toArray,
+  reverse,
+  mapReverse,
+  forEach,
+  forEachWithIndex,
+  reduce,
+  reduceWithIndex,
+  reduceReverse,
+  mapReverse2,
+  forEach2,
+  reduce2,
+  reduceReverse2,
+  every,
+  some,
+  every2,
+  some2,
+  compareLength,
+  compare,
+  equal,
+  has,
   find,
-  find_opt,
   filter,
-  find_all,
+  filterWithIndex,
+  filterMap,
   partition,
-  assoc,
-  assoc_opt,
-  assq,
-  assq_opt,
-  mem_assoc,
-  mem_assq,
-  remove_assoc,
-  remove_assq,
-  split,
-  combine,
+  unzip,
+  getAssoc,
+  hasAssoc,
+  removeAssoc,
+  setAssoc,
   sort,
-  stable_sort,
-  fast_sort,
-  sort_uniq,
-  merge,
 }
 /* No side effect */
diff --git a/lib/es6/Math.js b/lib/es6/Math.js
new file mode 100644
index 0000000000..964eb210be
--- /dev/null
+++ b/lib/es6/Math.js
@@ -0,0 +1,29 @@
+
+
+
+let Constants = {};
+
+function floor(f) {
+  return Math.floor(f) | 0;
+}
+
+function ceil(f) {
+  return Math.ceil(f) | 0;
+}
+
+function random(min, max) {
+  let f = Math.random() * (max - min | 0);
+  return (Math.floor(f) | 0) + min | 0;
+}
+
+let Int = {
+  floor: floor,
+  ceil: ceil,
+  random: random
+};
+
+export {
+  Constants,
+  Int,
+}
+/* No side effect */
diff --git a/lib/es6/Null.js b/lib/es6/Null.js
new file mode 100644
index 0000000000..42519ac00b
--- /dev/null
+++ b/lib/es6/Null.js
@@ -0,0 +1,86 @@
+
+
+import * as Option from "./Option.js";
+import * as Primitive_option from "./Primitive_option.js";
+
+function fromOption(option) {
+  if (option !== undefined) {
+    return Primitive_option.valFromOption(option);
+  }
+  
+}
+
+function equal(a, b, eq) {
+  return Option.equal((a == null) ? undefined : Primitive_option.some(a), (b == null) ? undefined : Primitive_option.some(b), eq);
+}
+
+function compare(a, b, cmp) {
+  return Option.compare((a == null) ? undefined : Primitive_option.some(a), (b == null) ? undefined : Primitive_option.some(b), cmp);
+}
+
+function getOr(value, $$default) {
+  if (value == null) {
+    return $$default;
+  } else {
+    return value;
+  }
+}
+
+function getExn(value) {
+  if (!(value == null)) {
+    return value;
+  }
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Null.getExn: value is null",
+    Error: new Error()
+  };
+}
+
+function forEach(value, f) {
+  if (!(value == null)) {
+    return f(value);
+  }
+  
+}
+
+function map(value, f) {
+  if (!(value == null)) {
+    return f(value);
+  }
+  
+}
+
+function mapOr(value, $$default, f) {
+  if (value == null) {
+    return $$default;
+  } else {
+    return f(value);
+  }
+}
+
+function flatMap(value, f) {
+  if (!(value == null)) {
+    return f(value);
+  }
+  
+}
+
+let getWithDefault = getOr;
+
+let mapWithDefault = mapOr;
+
+export {
+  equal,
+  compare,
+  fromOption,
+  getOr,
+  getWithDefault,
+  getExn,
+  forEach,
+  map,
+  mapOr,
+  mapWithDefault,
+  flatMap,
+}
+/* No side effect */
diff --git a/lib/es6/Nullable.js b/lib/es6/Nullable.js
new file mode 100644
index 0000000000..714f9d68a8
--- /dev/null
+++ b/lib/es6/Nullable.js
@@ -0,0 +1,88 @@
+
+
+import * as Option from "./Option.js";
+import * as Primitive_option from "./Primitive_option.js";
+
+function fromOption(option) {
+  if (option !== undefined) {
+    return Primitive_option.valFromOption(option);
+  }
+  
+}
+
+function equal(a, b, eq) {
+  return Option.equal(a === null ? undefined : Primitive_option.some(a), b === null ? undefined : Primitive_option.some(b), eq);
+}
+
+function compare(a, b, cmp) {
+  return Option.compare(a === null ? undefined : Primitive_option.some(a), b === null ? undefined : Primitive_option.some(b), cmp);
+}
+
+function getOr(value, $$default) {
+  if (value !== null) {
+    return value;
+  } else {
+    return $$default;
+  }
+}
+
+function getExn(value) {
+  if (value !== null) {
+    return value;
+  }
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Nullable.getExn: value is null or undefined",
+    Error: new Error()
+  };
+}
+
+function forEach(value, f) {
+  if (value !== null) {
+    return f(value);
+  }
+  
+}
+
+function map(value, f) {
+  if (value !== null) {
+    return f(value);
+  } else {
+    return value;
+  }
+}
+
+function mapOr(value, $$default, f) {
+  if (value !== null) {
+    return f(value);
+  } else {
+    return $$default;
+  }
+}
+
+function flatMap(value, f) {
+  if (value !== null) {
+    return f(value);
+  } else {
+    return value;
+  }
+}
+
+let getWithDefault = getOr;
+
+let mapWithDefault = mapOr;
+
+export {
+  equal,
+  compare,
+  fromOption,
+  getOr,
+  getWithDefault,
+  getExn,
+  forEach,
+  map,
+  mapOr,
+  mapWithDefault,
+  flatMap,
+}
+/* No side effect */
diff --git a/lib/es6/Object.js b/lib/es6/Object.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Object.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Option.js b/lib/es6/Option.js
new file mode 100644
index 0000000000..d869bbcd7b
--- /dev/null
+++ b/lib/es6/Option.js
@@ -0,0 +1,120 @@
+
+
+import * as $$Error from "./Error.js";
+import * as Primitive_option from "./Primitive_option.js";
+
+function filter(opt, p) {
+  if (opt !== undefined && p(Primitive_option.valFromOption(opt))) {
+    return opt;
+  }
+  
+}
+
+function forEach(opt, f) {
+  if (opt !== undefined) {
+    return f(Primitive_option.valFromOption(opt));
+  }
+  
+}
+
+function getExn(x, message) {
+  if (x !== undefined) {
+    return Primitive_option.valFromOption(x);
+  } else {
+    return $$Error.panic(message !== undefined ? message : "Option.getExn called for None value");
+  }
+}
+
+function mapOr(opt, $$default, f) {
+  if (opt !== undefined) {
+    return f(Primitive_option.valFromOption(opt));
+  } else {
+    return $$default;
+  }
+}
+
+function map(opt, f) {
+  if (opt !== undefined) {
+    return Primitive_option.some(f(Primitive_option.valFromOption(opt)));
+  }
+  
+}
+
+function flatMap(opt, f) {
+  if (opt !== undefined) {
+    return f(Primitive_option.valFromOption(opt));
+  }
+  
+}
+
+function getOr(opt, $$default) {
+  if (opt !== undefined) {
+    return Primitive_option.valFromOption(opt);
+  } else {
+    return $$default;
+  }
+}
+
+function orElse(opt, other) {
+  if (opt !== undefined) {
+    return opt;
+  } else {
+    return other;
+  }
+}
+
+function isSome(x) {
+  return x !== undefined;
+}
+
+function isNone(x) {
+  return x === undefined;
+}
+
+function equal(a, b, eq) {
+  if (a !== undefined) {
+    if (b !== undefined) {
+      return eq(Primitive_option.valFromOption(a), Primitive_option.valFromOption(b));
+    } else {
+      return false;
+    }
+  } else {
+    return b === undefined;
+  }
+}
+
+function compare(a, b, cmp) {
+  if (a !== undefined) {
+    if (b !== undefined) {
+      return cmp(Primitive_option.valFromOption(a), Primitive_option.valFromOption(b));
+    } else {
+      return 1;
+    }
+  } else if (b !== undefined) {
+    return -1;
+  } else {
+    return 0;
+  }
+}
+
+let mapWithDefault = mapOr;
+
+let getWithDefault = getOr;
+
+export {
+  filter,
+  forEach,
+  getExn,
+  mapOr,
+  mapWithDefault,
+  map,
+  flatMap,
+  getOr,
+  getWithDefault,
+  orElse,
+  isSome,
+  isNone,
+  equal,
+  compare,
+}
+/* No side effect */
diff --git a/lib/es6/Ordering.js b/lib/es6/Ordering.js
new file mode 100644
index 0000000000..c249cde65b
--- /dev/null
+++ b/lib/es6/Ordering.js
@@ -0,0 +1,37 @@
+
+
+
+function isLess(ord) {
+  return ord < 0;
+}
+
+function isEqual(ord) {
+  return ord === 0;
+}
+
+function isGreater(ord) {
+  return ord > 0;
+}
+
+function invert(ord) {
+  return - ord;
+}
+
+function fromInt(n) {
+  if (n < 0) {
+    return -1;
+  } else if (n > 0) {
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+export {
+  isLess,
+  isEqual,
+  isGreater,
+  invert,
+  fromInt,
+}
+/* No side effect */
diff --git a/lib/es6/Pervasives.js b/lib/es6/Pervasives.js
index 754d72f936..ee989cf955 100644
--- a/lib/es6/Pervasives.js
+++ b/lib/es6/Pervasives.js
@@ -1,5 +1,6 @@
 
 
+import * as $$Error from "./Error.js";
 import * as Primitive_exceptions from "./Primitive_exceptions.js";
 
 function failwith(s) {
@@ -18,7 +19,7 @@ function invalid_arg(s) {
   };
 }
 
-let Exit = /* @__PURE__ */Primitive_exceptions.create("Pervasives.Pervasives.Exit");
+let Exit = /* @__PURE__ */Primitive_exceptions.create("Pervasives.Exit");
 
 function abs(x) {
   if (x >= 0) {
@@ -115,28 +116,6 @@ function $at(l1, l2) {
   }
 }
 
-let Pervasives = {
-  failwith: failwith,
-  invalid_arg: invalid_arg,
-  Exit: Exit,
-  abs: abs,
-  lnot: lnot,
-  max_int: 2147483647,
-  min_int: min_int,
-  infinity: Infinity,
-  neg_infinity: -Infinity,
-  max_float: 1.79769313486231571e+308,
-  min_float: 2.22507385850720138e-308,
-  epsilon_float: 2.22044604925031308e-16,
-  classify_float: classify_float,
-  char_of_int: char_of_int,
-  string_of_bool: string_of_bool,
-  bool_of_string: bool_of_string,
-  bool_of_string_opt: bool_of_string_opt,
-  int_of_string_opt: int_of_string_opt,
-  $at: $at
-};
-
 let max_int = 2147483647;
 
 let infinity = Infinity;
@@ -149,8 +128,9 @@ let min_float = 2.22507385850720138e-308;
 
 let epsilon_float = 2.22044604925031308e-16;
 
+let panic = $$Error.panic;
+
 export {
-  Pervasives,
   failwith,
   invalid_arg,
   Exit,
@@ -170,5 +150,6 @@ export {
   bool_of_string_opt,
   int_of_string_opt,
   $at,
+  panic,
 }
 /* No side effect */
diff --git a/lib/es6/Promise.js b/lib/es6/Promise.js
new file mode 100644
index 0000000000..475b96b4d9
--- /dev/null
+++ b/lib/es6/Promise.js
@@ -0,0 +1,12 @@
+
+
+import * as Primitive_exceptions from "./Primitive_exceptions.js";
+
+function $$catch(promise, callback) {
+  return promise.catch(err => callback(Primitive_exceptions.internalToException(err)));
+}
+
+export {
+  $$catch,
+}
+/* No side effect */
diff --git a/lib/es6/RegExp.js b/lib/es6/RegExp.js
new file mode 100644
index 0000000000..e3ed57758e
--- /dev/null
+++ b/lib/es6/RegExp.js
@@ -0,0 +1,9 @@
+
+
+
+let Result = {};
+
+export {
+  Result,
+}
+/* No side effect */
diff --git a/lib/es6/Result.js b/lib/es6/Result.js
new file mode 100644
index 0000000000..bda5bad6c7
--- /dev/null
+++ b/lib/es6/Result.js
@@ -0,0 +1,130 @@
+
+
+
+function getExn(x) {
+  if (x.TAG === "Ok") {
+    return x._0;
+  }
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
+}
+
+function mapOr(opt, $$default, f) {
+  if (opt.TAG === "Ok") {
+    return f(opt._0);
+  } else {
+    return $$default;
+  }
+}
+
+function map(opt, f) {
+  if (opt.TAG === "Ok") {
+    return {
+      TAG: "Ok",
+      _0: f(opt._0)
+    };
+  } else {
+    return opt;
+  }
+}
+
+function flatMap(opt, f) {
+  if (opt.TAG === "Ok") {
+    return f(opt._0);
+  } else {
+    return opt;
+  }
+}
+
+function getOr(opt, $$default) {
+  if (opt.TAG === "Ok") {
+    return opt._0;
+  } else {
+    return $$default;
+  }
+}
+
+function isOk(x) {
+  if (x.TAG === "Ok") {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+function isError(x) {
+  if (x.TAG === "Ok") {
+    return false;
+  } else {
+    return true;
+  }
+}
+
+function equal(a, b, f) {
+  if (a.TAG === "Ok") {
+    if (b.TAG === "Ok") {
+      return f(a._0, b._0);
+    } else {
+      return false;
+    }
+  } else if (b.TAG === "Ok") {
+    return false;
+  } else {
+    return true;
+  }
+}
+
+function compare(a, b, f) {
+  if (a.TAG === "Ok") {
+    if (b.TAG === "Ok") {
+      return f(a._0, b._0);
+    } else {
+      return 1;
+    }
+  } else if (b.TAG === "Ok") {
+    return -1;
+  } else {
+    return 0;
+  }
+}
+
+function forEach(r, f) {
+  if (r.TAG === "Ok") {
+    return f(r._0);
+  }
+  
+}
+
+function mapError(r, f) {
+  if (r.TAG === "Ok") {
+    return r;
+  } else {
+    return {
+      TAG: "Error",
+      _0: f(r._0)
+    };
+  }
+}
+
+let mapWithDefault = mapOr;
+
+let getWithDefault = getOr;
+
+export {
+  getExn,
+  mapOr,
+  mapWithDefault,
+  map,
+  flatMap,
+  getOr,
+  getWithDefault,
+  isOk,
+  isError,
+  equal,
+  compare,
+  forEach,
+  mapError,
+}
+/* No side effect */
diff --git a/lib/es6/String.js b/lib/es6/String.js
index f4f200eb1c..d68111d2a3 100644
--- a/lib/es6/String.js
+++ b/lib/es6/String.js
@@ -1,323 +1,33 @@
 
 
-import * as Char from "./Char.js";
-import * as $$Array from "./Array.js";
-import * as Primitive_exceptions from "./Primitive_exceptions.js";
 
-function apply1(f, bytes) {
-  if (bytes.length === 0) {
-    return bytes;
+function indexOfOpt(s, search) {
+  let index = s.indexOf(search);
+  if (index !== -1) {
+    return index;
   }
-  let r = bytes.slice();
-  r[0] = f(bytes[0]);
-  return r;
+  
 }
 
-function concat(sep, xs) {
-  return $$Array.of_list(xs).join(sep);
-}
-
-function bos(str) {
-  return $$Array.map(str => str.codePointAt(0), Array.from(str));
-}
-
-function make(len, ch) {
-  return String.fromCodePoint(ch).repeat(len);
-}
-
-function init(len, f) {
-  return $$Array.init(len, i => String.fromCodePoint(f(i))).join("");
-}
-
-function sub(s, ofs, len) {
-  return String.fromCodePoint(...$$Array.sub(bos(s), ofs, len));
-}
-
-function iter(f, s) {
-  for (let i = 0, i_finish = s.length; i < i_finish; ++i) {
-    f(s.codePointAt(i));
-  }
-}
-
-function iteri(f, s) {
-  for (let i = 0, i_finish = s.length; i < i_finish; ++i) {
-    f(i, s.codePointAt(i));
-  }
-}
-
-function map(f, s) {
-  return String.fromCodePoint(...$$Array.map(f, bos(s)));
-}
-
-function mapi(f, s) {
-  return String.fromCodePoint(...$$Array.mapi(f, bos(s)));
-}
-
-function escaped(s) {
-  let needs_escape = _i => {
-    while (true) {
-      let i = _i;
-      if (i >= s.length) {
-        return false;
-      }
-      let match = s.codePointAt(i);
-      if (match < 32) {
-        return true;
-      }
-      if (match > 92 || match < 34) {
-        if (match >= 127) {
-          return true;
-        }
-        _i = i + 1 | 0;
-        continue;
-      }
-      if (match > 91 || match < 35) {
-        return true;
-      }
-      _i = i + 1 | 0;
-      continue;
-    };
-  };
-  if (!needs_escape(0)) {
-    return s;
-  }
-  let bytes = bos(s);
-  return $$Array.map(Char.escaped, bytes).join("");
-}
-
-function index_rec(s, lim, _i, c) {
-  while (true) {
-    let i = _i;
-    if (i >= lim) {
-      throw {
-        RE_EXN_ID: "Not_found",
-        Error: new Error()
-      };
-    }
-    if (s.codePointAt(i) === c) {
-      return i;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
-}
-
-function index(s, c) {
-  return index_rec(s, s.length, 0, c);
-}
-
-function index_rec_opt(s, lim, _i, c) {
-  while (true) {
-    let i = _i;
-    if (i >= lim) {
-      return;
-    }
-    if (s.codePointAt(i) === c) {
-      return i;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
-}
-
-function index_opt(s, c) {
-  return index_rec_opt(s, s.length, 0, c);
-}
-
-function index_from(s, i, c) {
-  let l = s.length;
-  if (i < 0 || i > l) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.index_from / Bytes.index_from",
-      Error: new Error()
-    };
-  }
-  return index_rec(s, l, i, c);
-}
-
-function index_from_opt(s, i, c) {
-  let l = s.length;
-  if (i < 0 || i > l) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.index_from_opt / Bytes.index_from_opt",
-      Error: new Error()
-    };
+function lastIndexOfOpt(s, search) {
+  let index = s.lastIndexOf(search);
+  if (index !== -1) {
+    return index;
   }
-  return index_rec_opt(s, l, i, c);
-}
-
-function rindex_rec(s, _i, c) {
-  while (true) {
-    let i = _i;
-    if (i < 0) {
-      throw {
-        RE_EXN_ID: "Not_found",
-        Error: new Error()
-      };
-    }
-    if (s.codePointAt(i) === c) {
-      return i;
-    }
-    _i = i - 1 | 0;
-    continue;
-  };
-}
-
-function rindex(s, c) {
-  return rindex_rec(s, s.length - 1 | 0, c);
-}
-
-function rindex_from(s, i, c) {
-  if (i < -1 || i >= s.length) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.rindex_from / Bytes.rindex_from",
-      Error: new Error()
-    };
-  }
-  return rindex_rec(s, i, c);
-}
-
-function rindex_rec_opt(s, _i, c) {
-  while (true) {
-    let i = _i;
-    if (i < 0) {
-      return;
-    }
-    if (s.codePointAt(i) === c) {
-      return i;
-    }
-    _i = i - 1 | 0;
-    continue;
-  };
-}
-
-function rindex_opt(s, c) {
-  return rindex_rec_opt(s, s.length - 1 | 0, c);
-}
-
-function rindex_from_opt(s, i, c) {
-  if (i < -1 || i >= s.length) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
-      Error: new Error()
-    };
-  }
-  return rindex_rec_opt(s, i, c);
-}
-
-function contains_from(s, i, c) {
-  let l = s.length;
-  if (i < 0 || i > l) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.contains_from / Bytes.contains_from",
-      Error: new Error()
-    };
-  }
-  try {
-    index_rec(s, l, i, c);
-    return true;
-  } catch (raw_exn) {
-    let exn = Primitive_exceptions.internalToException(raw_exn);
-    if (exn.RE_EXN_ID === "Not_found") {
-      return false;
-    }
-    throw exn;
-  }
-}
-
-function contains(s, c) {
-  return contains_from(s, 0, c);
-}
-
-function rcontains_from(s, i, c) {
-  if (i < 0 || i >= s.length) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.rcontains_from / Bytes.rcontains_from",
-      Error: new Error()
-    };
-  }
-  try {
-    rindex_rec(s, i, c);
-    return true;
-  } catch (raw_exn) {
-    let exn = Primitive_exceptions.internalToException(raw_exn);
-    if (exn.RE_EXN_ID === "Not_found") {
-      return false;
-    }
-    throw exn;
-  }
-}
-
-function uppercase_ascii(s) {
-  let bytes = bos(s);
-  return String.fromCodePoint(...$$Array.map(Char.uppercase_ascii, bytes));
-}
-
-function lowercase_ascii(s) {
-  let bytes = bos(s);
-  return String.fromCodePoint(...$$Array.map(Char.lowercase_ascii, bytes));
-}
-
-function capitalize_ascii(s) {
-  let bytes = bos(s);
-  return String.fromCodePoint(...apply1(Char.uppercase_ascii, bytes));
-}
-
-function uncapitalize_ascii(s) {
-  let bytes = bos(s);
-  return String.fromCodePoint(...apply1(Char.lowercase_ascii, bytes));
+  
 }
 
-function split_on_char(sep, s) {
-  let r = /* [] */0;
-  let j = s.length;
-  for (let i = s.length - 1 | 0; i >= 0; --i) {
-    if (s.codePointAt(i) === sep) {
-      r = {
-        hd: sub(s, i + 1 | 0, (j - i | 0) - 1 | 0),
-        tl: r
-      };
-      j = i;
-    }
-    
+function searchOpt(s, re) {
+  let index = s.search(re);
+  if (index !== -1) {
+    return index;
   }
-  return {
-    hd: sub(s, 0, j),
-    tl: r
-  };
+  
 }
 
 export {
-  make,
-  init,
-  sub,
-  concat,
-  iter,
-  iteri,
-  map,
-  mapi,
-  escaped,
-  index,
-  index_opt,
-  rindex,
-  rindex_opt,
-  index_from,
-  index_from_opt,
-  rindex_from,
-  rindex_from_opt,
-  contains,
-  contains_from,
-  rcontains_from,
-  uppercase_ascii,
-  lowercase_ascii,
-  capitalize_ascii,
-  uncapitalize_ascii,
-  split_on_char,
+  indexOfOpt,
+  lastIndexOfOpt,
+  searchOpt,
 }
 /* No side effect */
diff --git a/lib/es6/Symbol.js b/lib/es6/Symbol.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/Symbol.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Type.js b/lib/es6/Type.js
new file mode 100644
index 0000000000..9ee5d6e69d
--- /dev/null
+++ b/lib/es6/Type.js
@@ -0,0 +1,58 @@
+
+
+
+function classify(value) {
+  let match = Object.prototype.toString.call(value);
+  switch (match) {
+    case "[object BigInt]" :
+      return {
+        TAG: "BigInt",
+        _0: value
+      };
+    case "[object Boolean]" :
+      return {
+        TAG: "Bool",
+        _0: value
+      };
+    case "[object AsyncFunction]" :
+    case "[object Function]" :
+    case "[object GeneratorFunction]" :
+      return {
+        TAG: "Function",
+        _0: value
+      };
+    case "[object Null]" :
+      return "Null";
+    case "[object Number]" :
+      return {
+        TAG: "Number",
+        _0: value
+      };
+    case "[object String]" :
+      return {
+        TAG: "String",
+        _0: value
+      };
+    case "[object Symbol]" :
+      return {
+        TAG: "Symbol",
+        _0: value
+      };
+    case "[object Undefined]" :
+      return "Undefined";
+    default:
+      return {
+        TAG: "Object",
+        _0: value
+      };
+  }
+}
+
+let Classify = {
+  classify: classify
+};
+
+export {
+  Classify,
+}
+/* No side effect */
diff --git a/lib/es6/TypedArray.js b/lib/es6/TypedArray.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/TypedArray.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/Uint16Array.js b/lib/es6/Uint16Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/Uint16Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/Uint32Array.js b/lib/es6/Uint32Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/Uint32Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/Uint8Array.js b/lib/es6/Uint8Array.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/Uint8Array.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/Uint8ClampedArray.js b/lib/es6/Uint8ClampedArray.js
new file mode 100644
index 0000000000..cd168743c9
--- /dev/null
+++ b/lib/es6/Uint8ClampedArray.js
@@ -0,0 +1,9 @@
+
+
+
+let Constants = {};
+
+export {
+  Constants,
+}
+/* No side effect */
diff --git a/lib/es6/WeakMap.js b/lib/es6/WeakMap.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/WeakMap.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/es6/WeakSet.js b/lib/es6/WeakSet.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/es6/WeakSet.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Array.js b/lib/js/Array.js
index 2e6213b61d..2af73849d4 100644
--- a/lib/js/Array.js
+++ b/lib/js/Array.js
@@ -1,495 +1,190 @@
 'use strict';
 
-let List = require("./List.js");
-let Primitive_array = require("./Primitive_array.js");
-let Primitive_exceptions = require("./Primitive_exceptions.js");
+let Primitive_option = require("./Primitive_option.js");
 
-let init = ((length, f) => Array.from({ length }, f));
-
-function make(len, x) {
-  return init(len, param => x);
-}
-
-function unsafe_sub(array, offset, length) {
-  return array.slice(offset, offset + length | 0);
-}
-
-function concat(list) {
-  return List.fold_left((arr1, arr2) => arr1.concat(arr2), [], list);
-}
-
-function create_float(len) {
-  return init(len, param => 0.0);
-}
-
-function make_matrix(sx, sy, init$1) {
-  let x = [];
-  let res = init(sx, param => x);
-  for (let x$1 = 0; x$1 < sx; ++x$1) {
-    res[x$1] = init(sy, param => init$1);
+function make(length, x) {
+  if (length <= 0) {
+    return [];
   }
-  return res;
+  let arr = new Array(length);
+  arr.fill(x);
+  return arr;
 }
 
-function append(a1, a2) {
-  let l1 = a1.length;
-  if (l1 === 0) {
-    return a2.slice();
-  } else if (a2.length === 0) {
-    return unsafe_sub(a1, 0, l1);
-  } else {
-    return a1.concat(a2);
+function fromInitializer(length, f) {
+  if (length <= 0) {
+    return [];
   }
+  let arr = new Array(length);
+  for (let i = 0; i < length; ++i) {
+    arr[i] = f(i);
+  }
+  return arr;
 }
 
-function sub(a, ofs, len) {
-  if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.sub",
-      Error: new Error()
+function equal(a, b, eq) {
+  let len = a.length;
+  if (len === b.length) {
+    let _i = 0;
+    while (true) {
+      let i = _i;
+      if (i === len) {
+        return true;
+      }
+      if (!eq(a[i], b[i])) {
+        return false;
+      }
+      _i = i + 1 | 0;
+      continue;
     };
+  } else {
+    return false;
   }
-  return unsafe_sub(a, ofs, len);
 }
 
-function fill(a, ofs, len, v) {
-  if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.fill",
-      Error: new Error()
+function compare(a, b, cmp) {
+  let lenA = a.length;
+  let lenB = b.length;
+  if (lenA < lenB) {
+    return -1;
+  } else if (lenA > lenB) {
+    return 1;
+  } else {
+    let _i = 0;
+    while (true) {
+      let i = _i;
+      if (i === lenA) {
+        return 0;
+      }
+      let c = cmp(a[i], b[i]);
+      if (c !== 0) {
+        return c;
+      }
+      _i = i + 1 | 0;
+      continue;
     };
   }
-  for (let i = ofs, i_finish = ofs + len | 0; i < i_finish; ++i) {
-    a[i] = v;
-  }
 }
 
-function blit(a1, ofs1, a2, ofs2, len) {
-  if (len < 0 || ofs1 < 0 || ofs1 > (a1.length - len | 0) || ofs2 < 0 || ofs2 > (a2.length - len | 0)) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.blit",
-      Error: new Error()
-    };
-  }
-  for (let i = 0; i < len; ++i) {
-    a2[ofs2 + i | 0] = a1[ofs1 + i | 0];
+function indexOfOpt(arr, item) {
+  let index = arr.indexOf(item);
+  if (index !== -1) {
+    return index;
   }
+  
 }
 
-function iter(f, a) {
-  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
-    f(a[i]);
+function lastIndexOfOpt(arr, item) {
+  let index = arr.lastIndexOf(item);
+  if (index !== -1) {
+    return index;
   }
+  
 }
 
-function iter2(f, a, b) {
-  if (a.length !== b.length) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.iter2: arrays must have the same length",
-      Error: new Error()
-    };
-  }
-  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
-    f(a[i], b[i]);
-  }
+function reduce(arr, init, f) {
+  return arr.reduce(f, init);
 }
 
-function map(f, a) {
-  let l = a.length;
-  if (l === 0) {
-    return [];
-  }
-  let x = f(a[0]);
-  let r = init(l, param => x);
-  for (let i = 1; i < l; ++i) {
-    r[i] = f(a[i]);
-  }
-  return r;
+function reduceWithIndex(arr, init, f) {
+  return arr.reduce(f, init);
 }
 
-function map2(f, a, b) {
-  let la = a.length;
-  let lb = b.length;
-  if (la !== lb) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.map2: arrays must have the same length",
-      Error: new Error()
-    };
-  }
-  if (la === 0) {
-    return [];
-  }
-  let x = f(a[0], b[0]);
-  let r = init(la, param => x);
-  for (let i = 1; i < la; ++i) {
-    r[i] = f(a[i], b[i]);
-  }
-  return r;
+function reduceRight(arr, init, f) {
+  return arr.reduceRight(f, init);
 }
 
-function iteri(f, a) {
-  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
-    f(i, a[i]);
-  }
+function reduceRightWithIndex(arr, init, f) {
+  return arr.reduceRight(f, init);
 }
 
-function mapi(f, a) {
-  let l = a.length;
-  if (l === 0) {
-    return [];
-  }
-  let x = f(0, a[0]);
-  let r = init(l, param => x);
-  for (let i = 1; i < l; ++i) {
-    r[i] = f(i, a[i]);
+function findIndexOpt(array, finder) {
+  let index = array.findIndex(finder);
+  if (index !== -1) {
+    return index;
   }
-  return r;
+  
 }
 
-function to_list(a) {
-  let _i = a.length - 1 | 0;
-  let _res = /* [] */0;
-  while (true) {
-    let res = _res;
-    let i = _i;
-    if (i < 0) {
-      return res;
-    }
-    _res = {
-      hd: a[i],
-      tl: res
-    };
-    _i = i - 1 | 0;
-    continue;
-  };
+function swapUnsafe(xs, i, j) {
+  let tmp = xs[i];
+  xs[i] = xs[j];
+  xs[j] = tmp;
 }
 
-function list_length(_accu, _param) {
-  while (true) {
-    let param = _param;
-    let accu = _accu;
-    if (!param) {
-      return accu;
-    }
-    _param = param.tl;
-    _accu = accu + 1 | 0;
-    continue;
-  };
+function random_int(min, max) {
+  return (Math.floor(Math.random() * (max - min | 0)) | 0) + min | 0;
 }
 
-function of_list(param) {
-  if (!param) {
-    return [];
+function shuffle(xs) {
+  let len = xs.length;
+  for (let i = 0; i < len; ++i) {
+    swapUnsafe(xs, i, random_int(i, len));
   }
-  let hd = param.hd;
-  let len = list_length(0, param);
-  let a = init(len, param => hd);
-  let _i = 1;
-  let _param = param.tl;
-  while (true) {
-    let param$1 = _param;
-    let i = _i;
-    if (!param$1) {
-      return a;
-    }
-    a[i] = param$1.hd;
-    _param = param$1.tl;
-    _i = i + 1 | 0;
-    continue;
-  };
 }
 
-function fold_left(f, x, a) {
-  let r = x;
-  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
-    r = f(r, a[i]);
-  }
-  return r;
+function toShuffled(xs) {
+  let result = xs.slice();
+  shuffle(result);
+  return result;
 }
 
-function fold_right(f, a, x) {
-  let r = x;
-  for (let i = a.length - 1 | 0; i >= 0; --i) {
-    r = f(a[i], r);
-  }
+function filterMap(a, f) {
+  let l = a.length;
+  let r = new Array(l);
+  let j = 0;
+  for (let i = 0; i < l; ++i) {
+    let v = a[i];
+    let v$1 = f(v);
+    if (v$1 !== undefined) {
+      r[j] = Primitive_option.valFromOption(v$1);
+      j = j + 1 | 0;
+    }
+    
+  }
+  r.length = j;
   return r;
 }
 
-function exists(p, a) {
-  let n = a.length;
-  let _i = 0;
-  while (true) {
-    let i = _i;
-    if (i === n) {
-      return false;
-    }
-    if (p(a[i])) {
-      return true;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
+function keepSome(__x) {
+  return filterMap(__x, x => x);
 }
 
-function for_all(p, a) {
-  let n = a.length;
+function findMap(arr, f) {
   let _i = 0;
   while (true) {
     let i = _i;
-    if (i === n) {
-      return true;
+    if (i === arr.length) {
+      return;
     }
-    if (!p(a[i])) {
-      return false;
+    let r = f(arr[i]);
+    if (r !== undefined) {
+      return r;
     }
     _i = i + 1 | 0;
     continue;
   };
 }
 
-function mem(x, a) {
-  let n = a.length;
-  let _i = 0;
-  while (true) {
-    let i = _i;
-    if (i === n) {
-      return false;
-    }
-    if (a[i] === x) {
-      return true;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
+function last(a) {
+  return a[a.length - 1 | 0];
 }
 
-function memq(x, a) {
-  let n = a.length;
-  let _i = 0;
-  while (true) {
-    let i = _i;
-    if (i === n) {
-      return false;
-    }
-    if (x === a[i]) {
-      return true;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
-}
-
-let Bottom = /* @__PURE__ */Primitive_exceptions.create("Array.Bottom");
-
-function sort(cmp, a) {
-  let maxson = (l, i) => {
-    let i31 = ((i + i | 0) + i | 0) + 1 | 0;
-    let x = i31;
-    if ((i31 + 2 | 0) < l) {
-      if (cmp(Primitive_array.get(a, i31), Primitive_array.get(a, i31 + 1 | 0)) < 0) {
-        x = i31 + 1 | 0;
-      }
-      if (cmp(Primitive_array.get(a, x), Primitive_array.get(a, i31 + 2 | 0)) < 0) {
-        x = i31 + 2 | 0;
-      }
-      return x;
-    }
-    if ((i31 + 1 | 0) < l && cmp(Primitive_array.get(a, i31), Primitive_array.get(a, i31 + 1 | 0)) < 0) {
-      return i31 + 1 | 0;
-    }
-    if (i31 < l) {
-      return i31;
-    }
-    throw {
-      RE_EXN_ID: Bottom,
-      _1: i,
-      Error: new Error()
-    };
-  };
-  let trickle = (l, i, e) => {
-    try {
-      let _i = i;
-      while (true) {
-        let i$1 = _i;
-        let j = maxson(l, i$1);
-        if (cmp(Primitive_array.get(a, j), e) <= 0) {
-          return Primitive_array.set(a, i$1, e);
-        }
-        Primitive_array.set(a, i$1, Primitive_array.get(a, j));
-        _i = j;
-        continue;
-      };
-    } catch (raw_i) {
-      let i$2 = Primitive_exceptions.internalToException(raw_i);
-      if (i$2.RE_EXN_ID === Bottom) {
-        return Primitive_array.set(a, i$2._1, e);
-      }
-      throw i$2;
-    }
-  };
-  let bubble = (l, i) => {
-    try {
-      let _i = i;
-      while (true) {
-        let i$1 = _i;
-        let j = maxson(l, i$1);
-        Primitive_array.set(a, i$1, Primitive_array.get(a, j));
-        _i = j;
-        continue;
-      };
-    } catch (raw_i) {
-      let i$2 = Primitive_exceptions.internalToException(raw_i);
-      if (i$2.RE_EXN_ID === Bottom) {
-        return i$2._1;
-      }
-      throw i$2;
-    }
-  };
-  let trickleup = (_i, e) => {
-    while (true) {
-      let i = _i;
-      let father = (i - 1 | 0) / 3 | 0;
-      if (i === father) {
-        throw {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "Array.res",
-            294,
-            4
-          ],
-          Error: new Error()
-        };
-      }
-      if (cmp(Primitive_array.get(a, father), e) >= 0) {
-        return Primitive_array.set(a, i, e);
-      }
-      Primitive_array.set(a, i, Primitive_array.get(a, father));
-      if (father <= 0) {
-        return Primitive_array.set(a, 0, e);
-      }
-      _i = father;
-      continue;
-    };
-  };
-  let l = a.length;
-  for (let i = ((l + 1 | 0) / 3 | 0) - 1 | 0; i >= 0; --i) {
-    trickle(l, i, Primitive_array.get(a, i));
-  }
-  for (let i$1 = l - 1 | 0; i$1 >= 2; --i$1) {
-    let e = Primitive_array.get(a, i$1);
-    Primitive_array.set(a, i$1, Primitive_array.get(a, 0));
-    trickleup(bubble(i$1, 0), e);
-  }
-  if (l <= 1) {
-    return;
-  }
-  let e$1 = Primitive_array.get(a, 1);
-  Primitive_array.set(a, 1, Primitive_array.get(a, 0));
-  Primitive_array.set(a, 0, e$1);
-}
-
-function stable_sort(cmp, a) {
-  let merge = (src1ofs, src1len, src2, src2ofs, src2len, dst, dstofs) => {
-    let src1r = src1ofs + src1len | 0;
-    let src2r = src2ofs + src2len | 0;
-    let _i1 = src1ofs;
-    let _s1 = Primitive_array.get(a, src1ofs);
-    let _i2 = src2ofs;
-    let _s2 = Primitive_array.get(src2, src2ofs);
-    let _d = dstofs;
-    while (true) {
-      let d = _d;
-      let s2 = _s2;
-      let i2 = _i2;
-      let s1 = _s1;
-      let i1 = _i1;
-      if (cmp(s1, s2) <= 0) {
-        Primitive_array.set(dst, d, s1);
-        let i1$1 = i1 + 1 | 0;
-        if (i1$1 >= src1r) {
-          return blit(src2, i2, dst, d + 1 | 0, src2r - i2 | 0);
-        }
-        _d = d + 1 | 0;
-        _s1 = Primitive_array.get(a, i1$1);
-        _i1 = i1$1;
-        continue;
-      }
-      Primitive_array.set(dst, d, s2);
-      let i2$1 = i2 + 1 | 0;
-      if (i2$1 >= src2r) {
-        return blit(a, i1, dst, d + 1 | 0, src1r - i1 | 0);
-      }
-      _d = d + 1 | 0;
-      _s2 = Primitive_array.get(src2, i2$1);
-      _i2 = i2$1;
-      continue;
-    };
-  };
-  let isortto = (srcofs, dst, dstofs, len) => {
-    for (let i = 0; i < len; ++i) {
-      let e = Primitive_array.get(a, srcofs + i | 0);
-      let j = (dstofs + i | 0) - 1 | 0;
-      while (j >= dstofs && cmp(Primitive_array.get(dst, j), e) > 0) {
-        Primitive_array.set(dst, j + 1 | 0, Primitive_array.get(dst, j));
-        j = j - 1 | 0;
-      };
-      Primitive_array.set(dst, j + 1 | 0, e);
-    }
-  };
-  let sortto = (srcofs, dst, dstofs, len) => {
-    if (len <= 5) {
-      return isortto(srcofs, dst, dstofs, len);
-    }
-    let l1 = len / 2 | 0;
-    let l2 = len - l1 | 0;
-    sortto(srcofs + l1 | 0, dst, dstofs + l1 | 0, l2);
-    sortto(srcofs, a, srcofs + l2 | 0, l1);
-    merge(srcofs + l2 | 0, l1, dst, dstofs + l1 | 0, l2, dst, dstofs);
-  };
-  let l = a.length;
-  if (l <= 5) {
-    return isortto(0, a, 0, l);
-  }
-  let l1 = l / 2 | 0;
-  let l2 = l - l1 | 0;
-  let x = Primitive_array.get(a, 0);
-  let t = init(l2, param => x);
-  sortto(l1, t, 0, l2);
-  sortto(0, a, l2, l1);
-  merge(l2, l1, t, 0, l2, a, 0);
-}
-
-let fast_sort = stable_sort;
-
 exports.make = make;
-exports.create_float = create_float;
-exports.init = init;
-exports.make_matrix = make_matrix;
-exports.append = append;
-exports.concat = concat;
-exports.sub = sub;
-exports.fill = fill;
-exports.blit = blit;
-exports.to_list = to_list;
-exports.of_list = of_list;
-exports.iter = iter;
-exports.iteri = iteri;
-exports.map = map;
-exports.mapi = mapi;
-exports.fold_left = fold_left;
-exports.fold_right = fold_right;
-exports.iter2 = iter2;
-exports.map2 = map2;
-exports.for_all = for_all;
-exports.exists = exists;
-exports.mem = mem;
-exports.memq = memq;
-exports.sort = sort;
-exports.stable_sort = stable_sort;
-exports.fast_sort = fast_sort;
+exports.fromInitializer = fromInitializer;
+exports.equal = equal;
+exports.compare = compare;
+exports.indexOfOpt = indexOfOpt;
+exports.lastIndexOfOpt = lastIndexOfOpt;
+exports.reduce = reduce;
+exports.reduceWithIndex = reduceWithIndex;
+exports.reduceRight = reduceRight;
+exports.reduceRightWithIndex = reduceRightWithIndex;
+exports.findIndexOpt = findIndexOpt;
+exports.filterMap = filterMap;
+exports.keepSome = keepSome;
+exports.toShuffled = toShuffled;
+exports.shuffle = shuffle;
+exports.findMap = findMap;
+exports.last = last;
 /* No side effect */
diff --git a/lib/js/ArrayBuffer.js b/lib/js/ArrayBuffer.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/ArrayBuffer.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/AsyncIterator.js b/lib/js/AsyncIterator.js
new file mode 100644
index 0000000000..c45654bafe
--- /dev/null
+++ b/lib/js/AsyncIterator.js
@@ -0,0 +1,41 @@
+'use strict';
+
+let Primitive_option = require("./Primitive_option.js");
+
+function value(v) {
+  return {
+    done: false,
+    value: Primitive_option.some(v)
+  };
+}
+
+function done(finalValue) {
+  return {
+    done: true,
+    value: finalValue
+  };
+}
+
+async function forEach(iterator, f) {
+  let iteratorDone = false;
+  while (!iteratorDone) {
+    let match = await iterator.next();
+    f(match.value);
+    iteratorDone = match.done;
+  };
+}
+
+let make = (function makeAsyncIterator(next) {
+  return {
+    next,
+    [Symbol.asyncIterator]() {
+      return this;
+    }
+  }
+});
+
+exports.make = make;
+exports.value = value;
+exports.done = done;
+exports.forEach = forEach;
+/* No side effect */
diff --git a/lib/js/BigInt.js b/lib/js/BigInt.js
new file mode 100644
index 0000000000..dbcaa74f96
--- /dev/null
+++ b/lib/js/BigInt.js
@@ -0,0 +1,14 @@
+'use strict';
+
+
+function toInt(t) {
+  return Number(t) | 0;
+}
+
+function lnot(x) {
+  return x ^ -1n;
+}
+
+exports.toInt = toInt;
+exports.lnot = lnot;
+/* No side effect */
diff --git a/lib/js/BigInt64Array.js b/lib/js/BigInt64Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/BigInt64Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/BigUint64Array.js b/lib/js/BigUint64Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/BigUint64Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/Console.js b/lib/js/Console.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Console.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/DataView.js b/lib/js/DataView.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/DataView.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Date.js b/lib/js/Date.js
new file mode 100644
index 0000000000..ef4be50a41
--- /dev/null
+++ b/lib/js/Date.js
@@ -0,0 +1,18 @@
+'use strict';
+
+let Primitive_float = require("./Primitive_float.js");
+
+let UTC = {};
+
+function equal(a, b) {
+  return a.getTime() === b.getTime();
+}
+
+function compare(a, b) {
+  return Primitive_float.compare(a.getTime(), b.getTime());
+}
+
+exports.UTC = UTC;
+exports.equal = equal;
+exports.compare = compare;
+/* No side effect */
diff --git a/lib/js/Dict.js b/lib/js/Dict.js
new file mode 100644
index 0000000000..4e8aab1fe0
--- /dev/null
+++ b/lib/js/Dict.js
@@ -0,0 +1,28 @@
+'use strict';
+
+
+function $$delete$1(dict, string) {
+  delete(dict[string]);
+}
+
+function forEach(dict, f) {
+  Object.values(dict).forEach(value => f(value));
+}
+
+function forEachWithKey(dict, f) {
+  Object.entries(dict).forEach(param => f(param[1], param[0]));
+}
+
+function mapValues(dict, f) {
+  let target = {};
+  forEachWithKey(dict, (value, key) => {
+    target[key] = f(value);
+  });
+  return target;
+}
+
+exports.$$delete = $$delete$1;
+exports.forEach = forEach;
+exports.forEachWithKey = forEachWithKey;
+exports.mapValues = mapValues;
+/* No side effect */
diff --git a/lib/js/Error.js b/lib/js/Error.js
new file mode 100644
index 0000000000..bb0913400c
--- /dev/null
+++ b/lib/js/Error.js
@@ -0,0 +1,27 @@
+'use strict';
+
+
+let $$EvalError = {};
+
+let $$RangeError = {};
+
+let $$ReferenceError = {};
+
+let $$SyntaxError = {};
+
+let $$TypeError = {};
+
+let $$URIError = {};
+
+function panic(msg) {
+  throw new Error("Panic! " + msg);
+}
+
+exports.$$EvalError = $$EvalError;
+exports.$$RangeError = $$RangeError;
+exports.$$ReferenceError = $$ReferenceError;
+exports.$$SyntaxError = $$SyntaxError;
+exports.$$TypeError = $$TypeError;
+exports.$$URIError = $$URIError;
+exports.panic = panic;
+/* No side effect */
diff --git a/lib/js/Js_exn.js b/lib/js/Exn.js
similarity index 100%
rename from lib/js/Js_exn.js
rename to lib/js/Exn.js
diff --git a/lib/js/Float.js b/lib/js/Float.js
new file mode 100644
index 0000000000..ecb91a0c04
--- /dev/null
+++ b/lib/js/Float.js
@@ -0,0 +1,27 @@
+'use strict';
+
+
+let Constants = {};
+
+function fromString(i) {
+  let i$1 = parseFloat(i);
+  if (isNaN(i$1)) {
+    return;
+  } else {
+    return i$1;
+  }
+}
+
+function clamp(min, max, value) {
+  let value$1 = max !== undefined && max < value ? max : value;
+  if (min !== undefined && min > value$1) {
+    return min;
+  } else {
+    return value$1;
+  }
+}
+
+exports.Constants = Constants;
+exports.fromString = fromString;
+exports.clamp = clamp;
+/* No side effect */
diff --git a/lib/js/Float32Array.js b/lib/js/Float32Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/Float32Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/Float64Array.js b/lib/js/Float64Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/Float64Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/Int.js b/lib/js/Int.js
new file mode 100644
index 0000000000..147f1cef99
--- /dev/null
+++ b/lib/js/Int.js
@@ -0,0 +1,84 @@
+'use strict';
+
+let $$Array = require("./Array.js");
+
+function fromString(x, radix) {
+  let maybeInt = radix !== undefined ? parseInt(x, radix) : parseInt(x);
+  if (isNaN(maybeInt) || maybeInt > 2147483647 || maybeInt < -2147483648) {
+    return;
+  } else {
+    return maybeInt | 0;
+  }
+}
+
+function abs(x) {
+  if (x >= 0) {
+    return x;
+  } else {
+    return -x | 0;
+  }
+}
+
+function range(start, end, optionsOpt) {
+  let options = optionsOpt !== undefined ? optionsOpt : ({});
+  let isInverted = start > end;
+  let n = options.step;
+  let step;
+  if (n !== undefined) {
+    if (n !== 0) {
+      step = n;
+    } else {
+      if (start !== end) {
+        throw new RangeError("Incorrect range arguments");
+      }
+      step = n;
+    }
+  } else {
+    step = isInverted ? -1 : 1;
+  }
+  let length;
+  if (isInverted === step >= 0) {
+    length = 0;
+  } else if (step === 0) {
+    length = options.inclusive === true ? 1 : 0;
+  } else {
+    let range$1 = isInverted ? start - end | 0 : end - start | 0;
+    let range$2 = options.inclusive === true ? range$1 + 1 | 0 : range$1;
+    length = Math.ceil(range$2 / abs(step)) | 0;
+  }
+  return $$Array.fromInitializer(length, i => start + Math.imul(i, step) | 0);
+}
+
+function rangeWithOptions(start, end, options) {
+  return range(start, end, options);
+}
+
+function clamp(min, max, value) {
+  let value$1 = max !== undefined && max < value ? max : value;
+  if (min !== undefined && min > value$1) {
+    return min;
+  } else {
+    return value$1;
+  }
+}
+
+function lnot(x) {
+  return x ^ -1;
+}
+
+let Bitwise = {
+  lnot: lnot
+};
+
+let Constants = {
+  minValue: -2147483648,
+  maxValue: 2147483647
+};
+
+exports.Constants = Constants;
+exports.fromString = fromString;
+exports.range = range;
+exports.rangeWithOptions = rangeWithOptions;
+exports.clamp = clamp;
+exports.Bitwise = Bitwise;
+/* No side effect */
diff --git a/lib/js/Int16Array.js b/lib/js/Int16Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/Int16Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/Int32Array.js b/lib/js/Int32Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/Int32Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/Int8Array.js b/lib/js/Int8Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/Int8Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/Intl.js b/lib/js/Intl.js
new file mode 100644
index 0000000000..58e3e0d4ca
--- /dev/null
+++ b/lib/js/Intl.js
@@ -0,0 +1,34 @@
+'use strict';
+
+
+let Common;
+
+let Collator;
+
+let DateTimeFormat;
+
+let ListFormat;
+
+let Locale;
+
+let NumberFormat;
+
+let PluralRules;
+
+let RelativeTimeFormat;
+
+let Segmenter;
+
+let Segments;
+
+exports.Common = Common;
+exports.Collator = Collator;
+exports.DateTimeFormat = DateTimeFormat;
+exports.ListFormat = ListFormat;
+exports.Locale = Locale;
+exports.NumberFormat = NumberFormat;
+exports.PluralRules = PluralRules;
+exports.RelativeTimeFormat = RelativeTimeFormat;
+exports.Segmenter = Segmenter;
+exports.Segments = Segments;
+/* No side effect */
diff --git a/lib/js/Intl_Collator.js b/lib/js/Intl_Collator.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Intl_Collator.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Intl_Common.js b/lib/js/Intl_Common.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Intl_Common.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Intl_DateTimeFormat.js b/lib/js/Intl_DateTimeFormat.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Intl_DateTimeFormat.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Intl_ListFormat.js b/lib/js/Intl_ListFormat.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Intl_ListFormat.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Intl_Locale.js b/lib/js/Intl_Locale.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Intl_Locale.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Intl_NumberFormat.js b/lib/js/Intl_NumberFormat.js
new file mode 100644
index 0000000000..0d1f1ed91f
--- /dev/null
+++ b/lib/js/Intl_NumberFormat.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Grouping;
+
+exports.Grouping = Grouping;
+/* No side effect */
diff --git a/lib/js/Intl_NumberFormat_Grouping.js b/lib/js/Intl_NumberFormat_Grouping.js
new file mode 100644
index 0000000000..56dd9f43eb
--- /dev/null
+++ b/lib/js/Intl_NumberFormat_Grouping.js
@@ -0,0 +1,33 @@
+'use strict';
+
+let Type = require("./Type.js");
+
+function parseJsValue(value) {
+  let value$1 = Type.Classify.classify(value);
+  if (typeof value$1 !== "object") {
+    return;
+  }
+  switch (value$1.TAG) {
+    case "Bool" :
+      return {
+        NAME: "bool",
+        VAL: value$1._0
+      };
+    case "String" :
+      switch (value$1._0) {
+        case "always" :
+          return "always";
+        case "auto" :
+          return "auto";
+        case "min2" :
+          return "min2";
+        default:
+          return;
+      }
+    default:
+      return;
+  }
+}
+
+exports.parseJsValue = parseJsValue;
+/* No side effect */
diff --git a/lib/js/Intl_PluralRules.js b/lib/js/Intl_PluralRules.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Intl_PluralRules.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Intl_RelativeTimeFormat.js b/lib/js/Intl_RelativeTimeFormat.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Intl_RelativeTimeFormat.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Intl_Segmenter.js b/lib/js/Intl_Segmenter.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Intl_Segmenter.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Intl_Segments.js b/lib/js/Intl_Segments.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Intl_Segments.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Iterator.js b/lib/js/Iterator.js
new file mode 100644
index 0000000000..e696f08b1a
--- /dev/null
+++ b/lib/js/Iterator.js
@@ -0,0 +1,14 @@
+'use strict';
+
+
+function forEach(iterator, f) {
+  let iteratorDone = false;
+  while (!iteratorDone) {
+    let match = iterator.next();
+    f(match.value);
+    iteratorDone = match.done;
+  };
+}
+
+exports.forEach = forEach;
+/* No side effect */
diff --git a/lib/js/JSON.js b/lib/js/JSON.js
new file mode 100644
index 0000000000..b3fe6b0f6e
--- /dev/null
+++ b/lib/js/JSON.js
@@ -0,0 +1,98 @@
+'use strict';
+
+let Primitive_option = require("./Primitive_option.js");
+
+function classify(value) {
+  let match = Object.prototype.toString.call(value);
+  switch (match) {
+    case "[object Array]" :
+      return {
+        TAG: "Array",
+        _0: value
+      };
+    case "[object Boolean]" :
+      return {
+        TAG: "Bool",
+        _0: value
+      };
+    case "[object Null]" :
+      return "Null";
+    case "[object Number]" :
+      return {
+        TAG: "Number",
+        _0: value
+      };
+    case "[object String]" :
+      return {
+        TAG: "String",
+        _0: value
+      };
+    default:
+      return {
+        TAG: "Object",
+        _0: value
+      };
+  }
+}
+
+let Classify = {
+  classify: classify
+};
+
+let Encode = {};
+
+function bool(json) {
+  if (typeof json === "boolean") {
+    return json;
+  }
+  
+}
+
+function $$null(json) {
+  if (json === undefined) {
+    return Primitive_option.some(undefined);
+  }
+  
+}
+
+function string(json) {
+  if (typeof json === "string") {
+    return json;
+  }
+  
+}
+
+function float(json) {
+  if (typeof json === "number") {
+    return json;
+  }
+  
+}
+
+function object(json) {
+  if (typeof json === "object" && !Array.isArray(json) && json !== undefined) {
+    return json;
+  }
+  
+}
+
+function array(json) {
+  if (Array.isArray(json)) {
+    return json;
+  }
+  
+}
+
+let Decode = {
+  bool: bool,
+  $$null: $$null,
+  string: string,
+  float: float,
+  object: object,
+  array: array
+};
+
+exports.Classify = Classify;
+exports.Encode = Encode;
+exports.Decode = Decode;
+/* No side effect */
diff --git a/lib/js/List.js b/lib/js/List.js
index 32a4309148..129fb6f5cf 100644
--- a/lib/js/List.js
+++ b/lib/js/List.js
@@ -1,1606 +1,957 @@
 'use strict';
 
-let Pervasives = require("./Pervasives.js");
+let $$Array = require("./Array.js");
+let Primitive_int = require("./Primitive_int.js");
 let Primitive_option = require("./Primitive_option.js");
 
-function length(l) {
-  let _len = 0;
-  let _param = l;
-  while (true) {
-    let param = _param;
-    let len = _len;
-    if (!param) {
-      return len;
-    }
-    _param = param.tl;
-    _len = len + 1 | 0;
-    continue;
-  };
-}
-
-function cons(a, l) {
-  return {
-    hd: a,
-    tl: l
-  };
+function head(x) {
+  if (x) {
+    return Primitive_option.some(x.hd);
+  }
+  
 }
 
-function hd(param) {
-  if (param) {
-    return param.hd;
+function headExn(x) {
+  if (x) {
+    return x.hd;
   }
   throw {
-    RE_EXN_ID: "Failure",
-    _1: "hd",
+    RE_EXN_ID: "Not_found",
     Error: new Error()
   };
 }
 
-function tl(param) {
-  if (param) {
-    return param.tl;
+function tail(x) {
+  if (x) {
+    return x.tl;
+  }
+  
+}
+
+function tailExn(x) {
+  if (x) {
+    return x.tl;
   }
   throw {
-    RE_EXN_ID: "Failure",
-    _1: "tl",
+    RE_EXN_ID: "Not_found",
     Error: new Error()
   };
 }
 
-function nth(l, n) {
+function add(xs, x) {
+  return {
+    hd: x,
+    tl: xs
+  };
+}
+
+function get(x, n) {
+  if (n < 0) {
+    return;
+  } else {
+    let _x = x;
+    let _n = n;
+    while (true) {
+      let n$1 = _n;
+      let x$1 = _x;
+      if (!x$1) {
+        return;
+      }
+      if (n$1 === 0) {
+        return Primitive_option.some(x$1.hd);
+      }
+      _n = n$1 - 1 | 0;
+      _x = x$1.tl;
+      continue;
+    };
+  }
+}
+
+function getExn(x, n) {
   if (n < 0) {
     throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.nth",
+      RE_EXN_ID: "Not_found",
       Error: new Error()
     };
   }
-  let _l = l;
+  let _x = x;
   let _n = n;
   while (true) {
     let n$1 = _n;
-    let l$1 = _l;
-    if (l$1) {
+    let x$1 = _x;
+    if (x$1) {
       if (n$1 === 0) {
-        return l$1.hd;
+        return x$1.hd;
       }
       _n = n$1 - 1 | 0;
-      _l = l$1.tl;
+      _x = x$1.tl;
       continue;
     }
     throw {
-      RE_EXN_ID: "Failure",
-      _1: "nth",
+      RE_EXN_ID: "Not_found",
       Error: new Error()
     };
   };
 }
 
-function nth_opt(l, n) {
-  if (n < 0) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.nth",
-      Error: new Error()
-    };
-  }
-  let _l = l;
-  let _n = n;
+function partitionAux(p, _cell, _precX, _precY) {
   while (true) {
-    let n$1 = _n;
-    let l$1 = _l;
-    if (!l$1) {
+    let precY = _precY;
+    let precX = _precX;
+    let cell = _cell;
+    if (!cell) {
       return;
     }
-    if (n$1 === 0) {
-      return Primitive_option.some(l$1.hd);
+    let t = cell.tl;
+    let h = cell.hd;
+    let next = {
+      hd: h,
+      tl: /* [] */0
+    };
+    if (p(h)) {
+      precX.tl = next;
+      _precX = next;
+      _cell = t;
+      continue;
     }
-    _n = n$1 - 1 | 0;
-    _l = l$1.tl;
+    precY.tl = next;
+    _precY = next;
+    _cell = t;
     continue;
   };
 }
 
-function rev_append(_l1, _l2) {
+function splitAux(_cell, _precX, _precY) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    if (!l1) {
-      return l2;
+    let precY = _precY;
+    let precX = _precX;
+    let cell = _cell;
+    if (!cell) {
+      return;
     }
-    _l2 = {
-      hd: l1.hd,
-      tl: l2
+    let match = cell.hd;
+    let nextA = {
+      hd: match[0],
+      tl: /* [] */0
     };
-    _l1 = l1.tl;
-    continue;
-  };
-}
-
-function rev(l) {
-  return rev_append(l, /* [] */0);
-}
-
-function init_tailrec_aux(_acc, _i, n, f) {
-  while (true) {
-    let i = _i;
-    let acc = _acc;
-    if (i >= n) {
-      return acc;
-    }
-    _i = i + 1 | 0;
-    _acc = {
-      hd: f(i),
-      tl: acc
+    let nextB = {
+      hd: match[1],
+      tl: /* [] */0
     };
+    precX.tl = nextA;
+    precY.tl = nextB;
+    _precY = nextB;
+    _precX = nextA;
+    _cell = cell.tl;
     continue;
   };
 }
 
-function init_aux(i, n, f) {
-  if (i >= n) {
-    return /* [] */0;
-  }
-  let r = f(i);
-  return {
-    hd: r,
-    tl: init_aux(i + 1 | 0, n, f)
-  };
-}
-
-function init(len, f) {
-  if (len < 0) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.init",
-      Error: new Error()
-    };
-  }
-  if (len > 10000) {
-    return rev_append(init_tailrec_aux(/* [] */0, 0, len, f), /* [] */0);
-  } else {
-    return init_aux(0, len, f);
-  }
-}
-
-function flatten(param) {
-  if (param) {
-    return Pervasives.$at(param.hd, flatten(param.tl));
-  } else {
-    return /* [] */0;
-  }
-}
-
-function map(f, param) {
-  if (!param) {
-    return /* [] */0;
-  }
-  let r = f(param.hd);
-  return {
-    hd: r,
-    tl: map(f, param.tl)
-  };
-}
-
-function mapi(i, f, param) {
-  if (!param) {
-    return /* [] */0;
-  }
-  let r = f(i, param.hd);
-  return {
-    hd: r,
-    tl: mapi(i + 1 | 0, f, param.tl)
-  };
-}
-
-function mapi$1(f, l) {
-  return mapi(0, f, l);
-}
-
-function rev_map(f, l) {
-  let _accu = /* [] */0;
-  let _param = l;
+function copyAuxCont(_cellX, _prec) {
   while (true) {
-    let param = _param;
-    let accu = _accu;
-    if (!param) {
-      return accu;
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
+      return prec;
     }
-    _param = param.tl;
-    _accu = {
-      hd: f(param.hd),
-      tl: accu
+    let next = {
+      hd: cellX.hd,
+      tl: /* [] */0
     };
+    prec.tl = next;
+    _prec = next;
+    _cellX = cellX.tl;
     continue;
   };
 }
 
-function iter(f, _param) {
+function copyAuxWitFilter(f, _cellX, _prec) {
   while (true) {
-    let param = _param;
-    if (!param) {
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
       return;
     }
-    f(param.hd);
-    _param = param.tl;
+    let t = cellX.tl;
+    let h = cellX.hd;
+    if (f(h)) {
+      let next = {
+        hd: h,
+        tl: /* [] */0
+      };
+      prec.tl = next;
+      _prec = next;
+      _cellX = t;
+      continue;
+    }
+    _cellX = t;
     continue;
   };
 }
 
-function iteri(f, l) {
-  let _i = 0;
-  let _param = l;
+function copyAuxWithFilterIndex(f, _cellX, _prec, _i) {
   while (true) {
-    let param = _param;
     let i = _i;
-    if (!param) {
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
       return;
     }
-    f(i, param.hd);
-    _param = param.tl;
+    let t = cellX.tl;
+    let h = cellX.hd;
+    if (f(h, i)) {
+      let next = {
+        hd: h,
+        tl: /* [] */0
+      };
+      prec.tl = next;
+      _i = i + 1 | 0;
+      _prec = next;
+      _cellX = t;
+      continue;
+    }
     _i = i + 1 | 0;
+    _cellX = t;
     continue;
   };
 }
 
-function fold_left(f, _accu, _l) {
+function copyAuxWitFilterMap(f, _cellX, _prec) {
   while (true) {
-    let l = _l;
-    let accu = _accu;
-    if (!l) {
-      return accu;
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
+      return;
     }
-    _l = l.tl;
-    _accu = f(accu, l.hd);
+    let t = cellX.tl;
+    let h = f(cellX.hd);
+    if (h !== undefined) {
+      let next = {
+        hd: Primitive_option.valFromOption(h),
+        tl: /* [] */0
+      };
+      prec.tl = next;
+      _prec = next;
+      _cellX = t;
+      continue;
+    }
+    _cellX = t;
     continue;
   };
 }
 
-function fold_right(f, l, accu) {
-  if (l) {
-    return f(l.hd, fold_right(f, l.tl, accu));
-  } else {
-    return accu;
-  }
-}
-
-function map2(f, l1, l2) {
-  if (l1) {
-    if (l2) {
-      let r = f(l1.hd, l2.hd);
-      return {
-        hd: r,
-        tl: map2(f, l1.tl, l2.tl)
-      };
+function removeAssocAuxWithMap(_cellX, x, _prec, f) {
+  while (true) {
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
+      return false;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.map2",
-      Error: new Error()
+    let t = cellX.tl;
+    let h = cellX.hd;
+    if (f(h[0], x)) {
+      prec.tl = t;
+      return true;
+    }
+    let next = {
+      hd: h,
+      tl: /* [] */0
     };
-  }
-  if (!l2) {
-    return /* [] */0;
-  }
-  throw {
-    RE_EXN_ID: "Invalid_argument",
-    _1: "List.map2",
-    Error: new Error()
+    prec.tl = next;
+    _prec = next;
+    _cellX = t;
+    continue;
   };
 }
 
-function rev_map2(f, l1, l2) {
-  let _accu = /* [] */0;
-  let _l1 = l1;
-  let _l2 = l2;
+function setAssocAuxWithMap(_cellX, x, k, _prec, eq) {
   while (true) {
-    let l2$1 = _l2;
-    let l1$1 = _l1;
-    let accu = _accu;
-    if (l1$1) {
-      if (l2$1) {
-        _l2 = l2$1.tl;
-        _l1 = l1$1.tl;
-        _accu = {
-          hd: f(l1$1.hd, l2$1.hd),
-          tl: accu
-        };
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.rev_map2",
-        Error: new Error()
-      };
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
+      return false;
     }
-    if (l2$1) {
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.rev_map2",
-        Error: new Error()
+    let t = cellX.tl;
+    let h = cellX.hd;
+    if (eq(h[0], x)) {
+      prec.tl = {
+        hd: [
+          x,
+          k
+        ],
+        tl: t
       };
+      return true;
     }
-    return accu;
+    let next = {
+      hd: h,
+      tl: /* [] */0
+    };
+    prec.tl = next;
+    _prec = next;
+    _cellX = t;
+    continue;
   };
 }
 
-function iter2(f, _l1, _l2) {
+function copyAuxWithMap(_cellX, _prec, f) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    if (l1) {
-      if (l2) {
-        f(l1.hd, l2.hd);
-        _l2 = l2.tl;
-        _l1 = l1.tl;
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.iter2",
-        Error: new Error()
-      };
-    }
-    if (!l2) {
+    let prec = _prec;
+    let cellX = _cellX;
+    if (!cellX) {
       return;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.iter2",
-      Error: new Error()
+    let next = {
+      hd: f(cellX.hd),
+      tl: /* [] */0
     };
+    prec.tl = next;
+    _prec = next;
+    _cellX = cellX.tl;
+    continue;
   };
 }
 
-function fold_left2(f, _accu, _l1, _l2) {
+function zipAux(_cellX, _cellY, _prec) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    let accu = _accu;
-    if (l1) {
-      if (l2) {
-        _l2 = l2.tl;
-        _l1 = l1.tl;
-        _accu = f(accu, l1.hd, l2.hd);
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_left2",
-        Error: new Error()
-      };
-    }
-    if (l2) {
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_left2",
-        Error: new Error()
-      };
+    let prec = _prec;
+    let cellY = _cellY;
+    let cellX = _cellX;
+    if (!cellX) {
+      return;
     }
-    return accu;
-  };
-}
-
-function fold_right2(f, l1, l2, accu) {
-  if (l1) {
-    if (l2) {
-      return f(l1.hd, l2.hd, fold_right2(f, l1.tl, l2.tl, accu));
+    if (!cellY) {
+      return;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.fold_right2",
-      Error: new Error()
-    };
-  }
-  if (l2) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.fold_right2",
-      Error: new Error()
+    let next = {
+      hd: [
+        cellX.hd,
+        cellY.hd
+      ],
+      tl: /* [] */0
     };
-  }
-  return accu;
-}
-
-function for_all(p, _param) {
-  while (true) {
-    let param = _param;
-    if (!param) {
-      return true;
-    }
-    if (!p(param.hd)) {
-      return false;
-    }
-    _param = param.tl;
+    prec.tl = next;
+    _prec = next;
+    _cellY = cellY.tl;
+    _cellX = cellX.tl;
     continue;
   };
 }
 
-function exists(p, _param) {
+function copyAuxWithMap2(f, _cellX, _cellY, _prec) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
+    let prec = _prec;
+    let cellY = _cellY;
+    let cellX = _cellX;
+    if (!cellX) {
+      return;
     }
-    if (p(param.hd)) {
-      return true;
+    if (!cellY) {
+      return;
     }
-    _param = param.tl;
+    let next = {
+      hd: f(cellX.hd, cellY.hd),
+      tl: /* [] */0
+    };
+    prec.tl = next;
+    _prec = next;
+    _cellY = cellY.tl;
+    _cellX = cellX.tl;
     continue;
   };
 }
 
-function for_all2(p, _l1, _l2) {
+function copyAuxWithMapI(f, _i, _cellX, _prec) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    if (l1) {
-      if (l2) {
-        if (!p(l1.hd, l2.hd)) {
-          return false;
-        }
-        _l2 = l2.tl;
-        _l1 = l1.tl;
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.for_all2",
-        Error: new Error()
-      };
-    }
-    if (!l2) {
-      return true;
+    let prec = _prec;
+    let cellX = _cellX;
+    let i = _i;
+    if (!cellX) {
+      return;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.for_all2",
-      Error: new Error()
+    let next = {
+      hd: f(cellX.hd, i),
+      tl: /* [] */0
     };
+    prec.tl = next;
+    _prec = next;
+    _cellX = cellX.tl;
+    _i = i + 1 | 0;
+    continue;
   };
 }
 
-function exists2(p, _l1, _l2) {
+function takeAux(_n, _cell, _prec) {
   while (true) {
-    let l2 = _l2;
-    let l1 = _l1;
-    if (l1) {
-      if (l2) {
-        if (p(l1.hd, l2.hd)) {
-          return true;
-        }
-        _l2 = l2.tl;
-        _l1 = l1.tl;
-        continue;
-      }
-      throw {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.exists2",
-        Error: new Error()
-      };
+    let prec = _prec;
+    let cell = _cell;
+    let n = _n;
+    if (n === 0) {
+      return true;
     }
-    if (!l2) {
+    if (!cell) {
       return false;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.exists2",
-      Error: new Error()
+    let cell$1 = {
+      hd: cell.hd,
+      tl: /* [] */0
     };
+    prec.tl = cell$1;
+    _prec = cell$1;
+    _cell = cell.tl;
+    _n = n - 1 | 0;
+    continue;
   };
 }
 
-function mem(x, _param) {
+function splitAtAux(_n, _cell, _prec) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
+    let prec = _prec;
+    let cell = _cell;
+    let n = _n;
+    if (n === 0) {
+      return cell;
     }
-    if (param.hd === x) {
-      return true;
+    if (!cell) {
+      return;
     }
-    _param = param.tl;
+    let cell$1 = {
+      hd: cell.hd,
+      tl: /* [] */0
+    };
+    prec.tl = cell$1;
+    _prec = cell$1;
+    _cell = cell.tl;
+    _n = n - 1 | 0;
     continue;
   };
 }
 
-function memq(x, _param) {
-  while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
-    }
-    if (param.hd === x) {
-      return true;
-    }
-    _param = param.tl;
-    continue;
+function take(lst, n) {
+  if (n < 0) {
+    return;
+  }
+  if (n === 0) {
+    return /* [] */0;
+  }
+  if (!lst) {
+    return;
+  }
+  let cell = {
+    hd: lst.hd,
+    tl: /* [] */0
   };
+  let has = takeAux(n - 1 | 0, lst.tl, cell);
+  if (has) {
+    return cell;
+  }
+  
 }
 
-function assoc(x, _param) {
-  while (true) {
-    let param = _param;
-    if (param) {
-      let match = param.hd;
-      if (match[0] === x) {
-        return match[1];
+function drop(lst, n) {
+  if (n < 0) {
+    return;
+  } else {
+    let _l = lst;
+    let _n = n;
+    while (true) {
+      let n$1 = _n;
+      let l = _l;
+      if (n$1 === 0) {
+        return l;
       }
-      _param = param.tl;
+      if (!l) {
+        return;
+      }
+      _n = n$1 - 1 | 0;
+      _l = l.tl;
       continue;
-    }
-    throw {
-      RE_EXN_ID: "Not_found",
-      Error: new Error()
     };
+  }
+}
+
+function splitAt(lst, n) {
+  if (n < 0) {
+    return;
+  }
+  if (n === 0) {
+    return [
+      /* [] */0,
+      lst
+    ];
+  }
+  if (!lst) {
+    return;
+  }
+  let cell = {
+    hd: lst.hd,
+    tl: /* [] */0
   };
+  let rest = splitAtAux(n - 1 | 0, lst.tl, cell);
+  if (rest !== undefined) {
+    return [
+      cell,
+      rest
+    ];
+  }
+  
 }
 
-function assoc_opt(x, _param) {
+function concat(xs, ys) {
+  if (!xs) {
+    return ys;
+  }
+  let cell = {
+    hd: xs.hd,
+    tl: /* [] */0
+  };
+  copyAuxCont(xs.tl, cell).tl = ys;
+  return cell;
+}
+
+function map(xs, f) {
+  if (!xs) {
+    return /* [] */0;
+  }
+  let cell = {
+    hd: f(xs.hd),
+    tl: /* [] */0
+  };
+  copyAuxWithMap(xs.tl, cell, f);
+  return cell;
+}
+
+function zipBy(l1, l2, f) {
+  if (!l1) {
+    return /* [] */0;
+  }
+  if (!l2) {
+    return /* [] */0;
+  }
+  let cell = {
+    hd: f(l1.hd, l2.hd),
+    tl: /* [] */0
+  };
+  copyAuxWithMap2(f, l1.tl, l2.tl, cell);
+  return cell;
+}
+
+function mapWithIndex(xs, f) {
+  if (!xs) {
+    return /* [] */0;
+  }
+  let cell = {
+    hd: f(xs.hd, 0),
+    tl: /* [] */0
+  };
+  copyAuxWithMapI(f, 1, xs.tl, cell);
+  return cell;
+}
+
+function fromInitializer(n, f) {
+  if (n <= 0) {
+    return /* [] */0;
+  }
+  let headX = {
+    hd: f(0),
+    tl: /* [] */0
+  };
+  let cur = headX;
+  let i = 1;
+  while (i < n) {
+    let v = {
+      hd: f(i),
+      tl: /* [] */0
+    };
+    cur.tl = v;
+    cur = v;
+    i = i + 1 | 0;
+  };
+  return headX;
+}
+
+function make(n, v) {
+  if (n <= 0) {
+    return /* [] */0;
+  }
+  let headX = {
+    hd: v,
+    tl: /* [] */0
+  };
+  let cur = headX;
+  let i = 1;
+  while (i < n) {
+    let v$1 = {
+      hd: v,
+      tl: /* [] */0
+    };
+    cur.tl = v$1;
+    cur = v$1;
+    i = i + 1 | 0;
+  };
+  return headX;
+}
+
+function length(xs) {
+  let _x = xs;
+  let _acc = 0;
   while (true) {
-    let param = _param;
-    if (!param) {
-      return;
+    let acc = _acc;
+    let x = _x;
+    if (!x) {
+      return acc;
     }
-    let match = param.hd;
-    if (match[0] === x) {
-      return Primitive_option.some(match[1]);
+    _acc = acc + 1 | 0;
+    _x = x.tl;
+    continue;
+  };
+}
+
+function fillAux(arr, _i, _x) {
+  while (true) {
+    let x = _x;
+    let i = _i;
+    if (!x) {
+      return;
     }
-    _param = param.tl;
+    arr[i] = x.hd;
+    _x = x.tl;
+    _i = i + 1 | 0;
     continue;
   };
 }
 
-function assq(x, _param) {
+function fromArray(a) {
+  let _i = a.length - 1 | 0;
+  let _res = /* [] */0;
   while (true) {
-    let param = _param;
-    if (param) {
-      let match = param.hd;
-      if (match[0] === x) {
-        return match[1];
-      }
-      _param = param.tl;
-      continue;
+    let res = _res;
+    let i = _i;
+    if (i < 0) {
+      return res;
     }
-    throw {
-      RE_EXN_ID: "Not_found",
-      Error: new Error()
+    _res = {
+      hd: a[i],
+      tl: res
     };
+    _i = i - 1 | 0;
+    continue;
   };
 }
 
-function assq_opt(x, _param) {
+function toArray(x) {
+  let len = length(x);
+  let arr = new Array(len);
+  fillAux(arr, 0, x);
+  return arr;
+}
+
+function toShuffled(xs) {
+  let v = toArray(xs);
+  $$Array.shuffle(v);
+  return fromArray(v);
+}
+
+function reverseConcat(_l1, _l2) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return;
-    }
-    let match = param.hd;
-    if (match[0] === x) {
-      return Primitive_option.some(match[1]);
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return l2;
     }
-    _param = param.tl;
+    _l2 = {
+      hd: l1.hd,
+      tl: l2
+    };
+    _l1 = l1.tl;
     continue;
   };
 }
 
-function mem_assoc(x, _param) {
+function reverse(l) {
+  return reverseConcat(l, /* [] */0);
+}
+
+function flatAux(_prec, _xs) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
-    }
-    if (param.hd[0] === x) {
-      return true;
+    let xs = _xs;
+    let prec = _prec;
+    if (xs) {
+      _xs = xs.tl;
+      _prec = copyAuxCont(xs.hd, prec);
+      continue;
     }
-    _param = param.tl;
-    continue;
+    prec.tl = /* [] */0;
+    return;
   };
 }
 
-function mem_assq(x, _param) {
+function flat(_xs) {
   while (true) {
-    let param = _param;
-    if (!param) {
-      return false;
+    let xs = _xs;
+    if (!xs) {
+      return /* [] */0;
     }
-    if (param.hd[0] === x) {
-      return true;
+    let match = xs.hd;
+    if (match) {
+      let cell = {
+        hd: match.hd,
+        tl: /* [] */0
+      };
+      flatAux(copyAuxCont(match.tl, cell), xs.tl);
+      return cell;
     }
-    _param = param.tl;
+    _xs = xs.tl;
     continue;
   };
 }
 
-function remove_assoc(x, param) {
-  if (!param) {
-    return /* [] */0;
+function concatMany(xs) {
+  let len = xs.length;
+  if (len === 1) {
+    return xs[0];
   }
-  let l = param.tl;
-  let pair = param.hd;
-  if (pair[0] === x) {
-    return l;
-  } else {
-    return {
-      hd: pair,
-      tl: remove_assoc(x, l)
-    };
-  }
-}
-
-function remove_assq(x, param) {
-  if (!param) {
+  if (len === 0) {
     return /* [] */0;
   }
-  let l = param.tl;
-  let pair = param.hd;
-  if (pair[0] === x) {
-    return l;
-  } else {
-    return {
-      hd: pair,
-      tl: remove_assq(x, l)
-    };
+  let len$1 = xs.length;
+  let v = xs[len$1 - 1 | 0];
+  for (let i = len$1 - 2 | 0; i >= 0; --i) {
+    v = concat(xs[i], v);
   }
+  return v;
 }
 
-function find(p, _param) {
+function mapReverse(l, f) {
+  let _accu = /* [] */0;
+  let _xs = l;
   while (true) {
-    let param = _param;
-    if (param) {
-      let x = param.hd;
-      if (p(x)) {
-        return x;
-      }
-      _param = param.tl;
-      continue;
+    let xs = _xs;
+    let accu = _accu;
+    if (!xs) {
+      return accu;
     }
-    throw {
-      RE_EXN_ID: "Not_found",
-      Error: new Error()
+    _xs = xs.tl;
+    _accu = {
+      hd: f(xs.hd),
+      tl: accu
     };
+    continue;
   };
 }
 
-function find_opt(p, _param) {
+function forEach(_xs, f) {
   while (true) {
-    let param = _param;
-    if (!param) {
+    let xs = _xs;
+    if (!xs) {
       return;
     }
-    let x = param.hd;
-    if (p(x)) {
-      return Primitive_option.some(x);
+    f(xs.hd);
+    _xs = xs.tl;
+    continue;
+  };
+}
+
+function forEachWithIndex(l, f) {
+  let _xs = l;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    let xs = _xs;
+    if (!xs) {
+      return;
     }
-    _param = param.tl;
+    f(xs.hd, i);
+    _i = i + 1 | 0;
+    _xs = xs.tl;
     continue;
   };
 }
 
-function find_all(p, l) {
-  let _accu = /* [] */0;
-  let _param = l;
+function reduce(_l, _accu, f) {
   while (true) {
-    let param = _param;
     let accu = _accu;
-    if (!param) {
-      return rev_append(accu, /* [] */0);
+    let l = _l;
+    if (!l) {
+      return accu;
     }
-    let l$1 = param.tl;
-    let x = param.hd;
-    if (p(x)) {
-      _param = l$1;
-      _accu = {
-        hd: x,
-        tl: accu
-      };
-      continue;
+    _accu = f(accu, l.hd);
+    _l = l.tl;
+    continue;
+  };
+}
+
+function reduceReverseUnsafe(l, accu, f) {
+  if (l) {
+    return f(reduceReverseUnsafe(l.tl, accu, f), l.hd);
+  } else {
+    return accu;
+  }
+}
+
+function reduceReverse(l, acc, f) {
+  let len = length(l);
+  if (len < 1000) {
+    return reduceReverseUnsafe(l, acc, f);
+  } else {
+    let a = toArray(l);
+    let r = acc;
+    for (let i = a.length - 1 | 0; i >= 0; --i) {
+      r = f(r, a[i]);
     }
-    _param = l$1;
+    return r;
+  }
+}
+
+function reduceWithIndex(l, acc, f) {
+  let _l = l;
+  let _acc = acc;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    let acc$1 = _acc;
+    let l$1 = _l;
+    if (!l$1) {
+      return acc$1;
+    }
+    _i = i + 1 | 0;
+    _acc = f(acc$1, l$1.hd, i);
+    _l = l$1.tl;
     continue;
   };
 }
 
-function partition(p, l) {
-  let _yes = /* [] */0;
-  let _no = /* [] */0;
-  let _param = l;
+function mapReverse2(l1, l2, f) {
+  let _l1 = l1;
+  let _l2 = l2;
+  let _accu = /* [] */0;
   while (true) {
-    let param = _param;
-    let no = _no;
-    let yes = _yes;
-    if (!param) {
-      return [
-        rev_append(yes, /* [] */0),
-        rev_append(no, /* [] */0)
-      ];
-    }
-    let l$1 = param.tl;
-    let x = param.hd;
-    if (p(x)) {
-      _param = l$1;
-      _yes = {
-        hd: x,
-        tl: yes
-      };
-      continue;
+    let accu = _accu;
+    let l2$1 = _l2;
+    let l1$1 = _l1;
+    if (!l1$1) {
+      return accu;
     }
-    _param = l$1;
-    _no = {
-      hd: x,
-      tl: no
+    if (!l2$1) {
+      return accu;
+    }
+    _accu = {
+      hd: f(l1$1.hd, l2$1.hd),
+      tl: accu
     };
+    _l2 = l2$1.tl;
+    _l1 = l1$1.tl;
     continue;
   };
 }
 
-function split(param) {
-  if (!param) {
-    return [
-      /* [] */0,
-      /* [] */0
-    ];
-  }
-  let match = param.hd;
-  let match$1 = split(param.tl);
-  return [
-    {
-      hd: match[0],
-      tl: match$1[0]
-    },
-    {
-      hd: match[1],
-      tl: match$1[1]
+function forEach2(_l1, _l2, f) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return;
     }
-  ];
+    if (!l2) {
+      return;
+    }
+    f(l1.hd, l2.hd);
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
 }
 
-function combine(l1, l2) {
-  if (l1) {
-    if (l2) {
-      return {
-        hd: [
-          l1.hd,
-          l2.hd
-        ],
-        tl: combine(l1.tl, l2.tl)
-      };
+function reduce2(_l1, _l2, _accu, f) {
+  while (true) {
+    let accu = _accu;
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return accu;
     }
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.combine",
-      Error: new Error()
-    };
-  }
-  if (!l2) {
-    return /* [] */0;
-  }
-  throw {
-    RE_EXN_ID: "Invalid_argument",
-    _1: "List.combine",
-    Error: new Error()
+    if (!l2) {
+      return accu;
+    }
+    _accu = f(accu, l1.hd, l2.hd);
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
   };
 }
 
-function merge(cmp, l1, l2) {
-  if (!l1) {
-    return l2;
-  }
-  if (!l2) {
-    return l1;
+function reduceReverse2Unsafe(l1, l2, accu, f) {
+  if (l1 && l2) {
+    return f(reduceReverse2Unsafe(l1.tl, l2.tl, accu, f), l1.hd, l2.hd);
+  } else {
+    return accu;
   }
-  let h2 = l2.hd;
-  let h1 = l1.hd;
-  if (cmp(h1, h2) <= 0) {
-    return {
-      hd: h1,
-      tl: merge(cmp, l1.tl, l2)
-    };
+}
+
+function reduceReverse2(l1, l2, acc, f) {
+  let len = length(l1);
+  if (len < 1000) {
+    return reduceReverse2Unsafe(l1, l2, acc, f);
   } else {
-    return {
-      hd: h2,
-      tl: merge(cmp, l1, l2.tl)
-    };
+    let a = toArray(l1);
+    let b = toArray(l2);
+    let r = acc;
+    let len$1 = Primitive_int.max(a.length, b.length);
+    for (let i = len$1 - 1 | 0; i >= 0; --i) {
+      r = f(r, a[i], b[i]);
+    }
+    return r;
   }
 }
 
-function chop(_k, _l) {
+function every(_xs, p) {
   while (true) {
-    let l = _l;
-    let k = _k;
-    if (k === 0) {
-      return l;
+    let xs = _xs;
+    if (!xs) {
+      return true;
     }
-    if (l) {
-      _l = l.tl;
-      _k = k - 1 | 0;
-      continue;
+    if (!p(xs.hd)) {
+      return false;
     }
-    throw {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "List.res",
-        411,
-        11
-      ],
-      Error: new Error()
-    };
+    _xs = xs.tl;
+    continue;
   };
 }
 
-function stable_sort(cmp, l) {
-  let sort = (n, l) => {
-    if (n !== 2) {
-      if (n === 3 && l) {
-        let match = l.tl;
-        if (match) {
-          let match$1 = match.tl;
-          if (match$1) {
-            let x3 = match$1.hd;
-            let x2 = match.hd;
-            let x1 = l.hd;
-            if (cmp(x1, x2) <= 0) {
-              if (cmp(x2, x3) <= 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: {
-                      hd: x3,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else if (cmp(x1, x3) <= 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-            } else if (cmp(x1, x3) <= 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else if (cmp(x2, x3) <= 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else {
-              return {
-                hd: x3,
-                tl: {
-                  hd: x2,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-          }
-          
-        }
-        
-      }
-      
-    } else if (l) {
-      let match$2 = l.tl;
-      if (match$2) {
-        let x2$1 = match$2.hd;
-        let x1$1 = l.hd;
-        if (cmp(x1$1, x2$1) <= 0) {
-          return {
-            hd: x1$1,
-            tl: {
-              hd: x2$1,
-              tl: /* [] */0
-            }
-          };
-        } else {
-          return {
-            hd: x2$1,
-            tl: {
-              hd: x1$1,
-              tl: /* [] */0
-            }
-          };
-        }
-      }
-      
-    }
-    let n1 = (n >> 1);
-    let n2 = n - n1 | 0;
-    let l2 = chop(n1, l);
-    let s1 = rev_sort(n1, l);
-    let s2 = rev_sort(n2, l2);
-    let _l1 = s1;
-    let _l2 = s2;
-    let _accu = /* [] */0;
-    while (true) {
-      let accu = _accu;
-      let l2$1 = _l2;
-      let l1 = _l1;
-      if (!l1) {
-        return rev_append(l2$1, accu);
-      }
-      if (!l2$1) {
-        return rev_append(l1, accu);
-      }
-      let h2 = l2$1.hd;
-      let h1 = l1.hd;
-      if (cmp(h1, h2) > 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l1 = l1.tl;
-        continue;
-      }
-      _accu = {
-        hd: h2,
-        tl: accu
-      };
-      _l2 = l2$1.tl;
-      continue;
-    };
-  };
-  let rev_sort = (n, l) => {
-    if (n !== 2) {
-      if (n === 3 && l) {
-        let match = l.tl;
-        if (match) {
-          let match$1 = match.tl;
-          if (match$1) {
-            let x3 = match$1.hd;
-            let x2 = match.hd;
-            let x1 = l.hd;
-            if (cmp(x1, x2) > 0) {
-              if (cmp(x2, x3) > 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: {
-                      hd: x3,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else if (cmp(x1, x3) > 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-            } else if (cmp(x1, x3) > 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else if (cmp(x2, x3) > 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else {
-              return {
-                hd: x3,
-                tl: {
-                  hd: x2,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-          }
-          
-        }
-        
-      }
-      
-    } else if (l) {
-      let match$2 = l.tl;
-      if (match$2) {
-        let x2$1 = match$2.hd;
-        let x1$1 = l.hd;
-        if (cmp(x1$1, x2$1) > 0) {
-          return {
-            hd: x1$1,
-            tl: {
-              hd: x2$1,
-              tl: /* [] */0
-            }
-          };
-        } else {
-          return {
-            hd: x2$1,
-            tl: {
-              hd: x1$1,
-              tl: /* [] */0
-            }
-          };
-        }
-      }
-      
-    }
-    let n1 = (n >> 1);
-    let n2 = n - n1 | 0;
-    let l2 = chop(n1, l);
-    let s1 = sort(n1, l);
-    let s2 = sort(n2, l2);
-    let _l1 = s1;
-    let _l2 = s2;
-    let _accu = /* [] */0;
-    while (true) {
-      let accu = _accu;
-      let l2$1 = _l2;
-      let l1 = _l1;
-      if (!l1) {
-        return rev_append(l2$1, accu);
-      }
-      if (!l2$1) {
-        return rev_append(l1, accu);
-      }
-      let h2 = l2$1.hd;
-      let h1 = l1.hd;
-      if (cmp(h1, h2) <= 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l1 = l1.tl;
-        continue;
-      }
-      _accu = {
-        hd: h2,
-        tl: accu
-      };
-      _l2 = l2$1.tl;
-      continue;
-    };
+function some(_xs, p) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return false;
+    }
+    if (p(xs.hd)) {
+      return true;
+    }
+    _xs = xs.tl;
+    continue;
   };
-  let len = length(l);
-  if (len < 2) {
-    return l;
-  } else {
-    return sort(len, l);
-  }
 }
 
-function sort_uniq(cmp, l) {
-  let sort = (n, l) => {
-    if (n !== 2) {
-      if (n === 3 && l) {
-        let match = l.tl;
-        if (match) {
-          let match$1 = match.tl;
-          if (match$1) {
-            let x3 = match$1.hd;
-            let x2 = match.hd;
-            let x1 = l.hd;
-            let c = cmp(x1, x2);
-            if (c === 0) {
-              let c$1 = cmp(x2, x3);
-              if (c$1 === 0) {
-                return {
-                  hd: x2,
-                  tl: /* [] */0
-                };
-              } else if (c$1 < 0) {
-                return {
-                  hd: x2,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              }
-            }
-            if (c < 0) {
-              let c$2 = cmp(x2, x3);
-              if (c$2 === 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              }
-              if (c$2 < 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: {
-                      hd: x3,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-              let c$3 = cmp(x1, x3);
-              if (c$3 === 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              } else if (c$3 < 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-            }
-            let c$4 = cmp(x1, x3);
-            if (c$4 === 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: /* [] */0
-                }
-              };
-            }
-            if (c$4 < 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-            let c$5 = cmp(x2, x3);
-            if (c$5 === 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: /* [] */0
-                }
-              };
-            } else if (c$5 < 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else {
-              return {
-                hd: x3,
-                tl: {
-                  hd: x2,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-          }
-          
-        }
-        
-      }
-      
-    } else if (l) {
-      let match$2 = l.tl;
-      if (match$2) {
-        let x2$1 = match$2.hd;
-        let x1$1 = l.hd;
-        let c$6 = cmp(x1$1, x2$1);
-        if (c$6 === 0) {
-          return {
-            hd: x1$1,
-            tl: /* [] */0
-          };
-        } else if (c$6 < 0) {
-          return {
-            hd: x1$1,
-            tl: {
-              hd: x2$1,
-              tl: /* [] */0
-            }
-          };
-        } else {
-          return {
-            hd: x2$1,
-            tl: {
-              hd: x1$1,
-              tl: /* [] */0
-            }
-          };
-        }
-      }
-      
-    }
-    let n1 = (n >> 1);
-    let n2 = n - n1 | 0;
-    let l2 = chop(n1, l);
-    let s1 = rev_sort(n1, l);
-    let s2 = rev_sort(n2, l2);
-    let _l1 = s1;
-    let _l2 = s2;
-    let _accu = /* [] */0;
-    while (true) {
-      let accu = _accu;
-      let l2$1 = _l2;
-      let l1 = _l1;
-      if (!l1) {
-        return rev_append(l2$1, accu);
-      }
-      if (!l2$1) {
-        return rev_append(l1, accu);
-      }
-      let t2 = l2$1.tl;
-      let h2 = l2$1.hd;
-      let t1 = l1.tl;
-      let h1 = l1.hd;
-      let c$7 = cmp(h1, h2);
-      if (c$7 === 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l2 = t2;
-        _l1 = t1;
-        continue;
-      }
-      if (c$7 > 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l1 = t1;
-        continue;
-      }
-      _accu = {
-        hd: h2,
-        tl: accu
-      };
-      _l2 = t2;
-      continue;
-    };
-  };
-  let rev_sort = (n, l) => {
-    if (n !== 2) {
-      if (n === 3 && l) {
-        let match = l.tl;
-        if (match) {
-          let match$1 = match.tl;
-          if (match$1) {
-            let x3 = match$1.hd;
-            let x2 = match.hd;
-            let x1 = l.hd;
-            let c = cmp(x1, x2);
-            if (c === 0) {
-              let c$1 = cmp(x2, x3);
-              if (c$1 === 0) {
-                return {
-                  hd: x2,
-                  tl: /* [] */0
-                };
-              } else if (c$1 > 0) {
-                return {
-                  hd: x2,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              }
-            }
-            if (c > 0) {
-              let c$2 = cmp(x2, x3);
-              if (c$2 === 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              }
-              if (c$2 > 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: {
-                      hd: x3,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-              let c$3 = cmp(x1, x3);
-              if (c$3 === 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x2,
-                    tl: /* [] */0
-                  }
-                };
-              } else if (c$3 > 0) {
-                return {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              } else {
-                return {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: {
-                      hd: x2,
-                      tl: /* [] */0
-                    }
-                  }
-                };
-              }
-            }
-            let c$4 = cmp(x1, x3);
-            if (c$4 === 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: /* [] */0
-                }
-              };
-            }
-            if (c$4 > 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: {
-                    hd: x3,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-            let c$5 = cmp(x2, x3);
-            if (c$5 === 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x1,
-                  tl: /* [] */0
-                }
-              };
-            } else if (c$5 > 0) {
-              return {
-                hd: x2,
-                tl: {
-                  hd: x3,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            } else {
-              return {
-                hd: x3,
-                tl: {
-                  hd: x2,
-                  tl: {
-                    hd: x1,
-                    tl: /* [] */0
-                  }
-                }
-              };
-            }
-          }
-          
-        }
-        
-      }
-      
-    } else if (l) {
-      let match$2 = l.tl;
-      if (match$2) {
-        let x2$1 = match$2.hd;
-        let x1$1 = l.hd;
-        let c$6 = cmp(x1$1, x2$1);
-        if (c$6 === 0) {
-          return {
-            hd: x1$1,
-            tl: /* [] */0
-          };
-        } else if (c$6 > 0) {
-          return {
-            hd: x1$1,
-            tl: {
-              hd: x2$1,
-              tl: /* [] */0
-            }
-          };
-        } else {
-          return {
-            hd: x2$1,
-            tl: {
-              hd: x1$1,
-              tl: /* [] */0
-            }
-          };
-        }
-      }
-      
-    }
-    let n1 = (n >> 1);
-    let n2 = n - n1 | 0;
-    let l2 = chop(n1, l);
-    let s1 = sort(n1, l);
-    let s2 = sort(n2, l2);
-    let _l1 = s1;
-    let _l2 = s2;
-    let _accu = /* [] */0;
-    while (true) {
-      let accu = _accu;
-      let l2$1 = _l2;
-      let l1 = _l1;
-      if (!l1) {
-        return rev_append(l2$1, accu);
-      }
-      if (!l2$1) {
-        return rev_append(l1, accu);
-      }
-      let t2 = l2$1.tl;
-      let h2 = l2$1.hd;
-      let t1 = l1.tl;
-      let h1 = l1.hd;
-      let c$7 = cmp(h1, h2);
-      if (c$7 === 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l2 = t2;
-        _l1 = t1;
-        continue;
-      }
-      if (c$7 < 0) {
-        _accu = {
-          hd: h1,
-          tl: accu
-        };
-        _l1 = t1;
-        continue;
-      }
-      _accu = {
-        hd: h2,
-        tl: accu
-      };
-      _l2 = t2;
-      continue;
-    };
+function every2(_l1, _l2, p) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return true;
+    }
+    if (!l2) {
+      return true;
+    }
+    if (!p(l1.hd, l2.hd)) {
+      return false;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
   };
-  let len = length(l);
-  if (len < 2) {
-    return l;
-  } else {
-    return sort(len, l);
-  }
 }
 
-function compare_lengths(_l1, _l2) {
+function compareLength(_l1, _l2) {
   while (true) {
     let l2 = _l2;
     let l1 = _l1;
@@ -1620,88 +971,390 @@ function compare_lengths(_l1, _l2) {
   };
 }
 
-function compare_length_with(_l, _n) {
+function compare(_l1, _l2, p) {
   while (true) {
-    let n = _n;
-    let l = _l;
-    if (!l) {
-      if (n === 0) {
-        return 0;
-      } else if (n > 0) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      if (l2) {
         return -1;
       } else {
-        return 1;
+        return 0;
       }
     }
-    if (n <= 0) {
+    if (!l2) {
       return 1;
     }
-    _n = n - 1 | 0;
-    _l = l.tl;
+    let c = p(l1.hd, l2.hd);
+    if (c !== 0) {
+      return c;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
+}
+
+function equal(_l1, _l2, p) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      if (l2) {
+        return false;
+      } else {
+        return true;
+      }
+    }
+    if (!l2) {
+      return false;
+    }
+    if (!p(l1.hd, l2.hd)) {
+      return false;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
+}
+
+function some2(_l1, _l2, p) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return false;
+    }
+    if (!l2) {
+      return false;
+    }
+    if (p(l1.hd, l2.hd)) {
+      return true;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
     continue;
   };
 }
 
-let append = Pervasives.$at;
+function has(_xs, x, eq) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return false;
+    }
+    if (eq(xs.hd, x)) {
+      return true;
+    }
+    _xs = xs.tl;
+    continue;
+  };
+}
+
+function getAssoc(_xs, x, eq) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return;
+    }
+    let match = xs.hd;
+    if (eq(match[0], x)) {
+      return Primitive_option.some(match[1]);
+    }
+    _xs = xs.tl;
+    continue;
+  };
+}
+
+function hasAssoc(_xs, x, eq) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return false;
+    }
+    if (eq(xs.hd[0], x)) {
+      return true;
+    }
+    _xs = xs.tl;
+    continue;
+  };
+}
+
+function removeAssoc(xs, x, eq) {
+  if (!xs) {
+    return /* [] */0;
+  }
+  let l = xs.tl;
+  let pair = xs.hd;
+  if (eq(pair[0], x)) {
+    return l;
+  }
+  let cell = {
+    hd: pair,
+    tl: /* [] */0
+  };
+  let removed = removeAssocAuxWithMap(l, x, cell, eq);
+  if (removed) {
+    return cell;
+  } else {
+    return xs;
+  }
+}
+
+function setAssoc(xs, x, k, eq) {
+  if (!xs) {
+    return {
+      hd: [
+        x,
+        k
+      ],
+      tl: /* [] */0
+    };
+  }
+  let l = xs.tl;
+  let pair = xs.hd;
+  if (eq(pair[0], x)) {
+    return {
+      hd: [
+        x,
+        k
+      ],
+      tl: l
+    };
+  }
+  let cell = {
+    hd: pair,
+    tl: /* [] */0
+  };
+  let replaced = setAssocAuxWithMap(l, x, k, cell, eq);
+  if (replaced) {
+    return cell;
+  } else {
+    return {
+      hd: [
+        x,
+        k
+      ],
+      tl: xs
+    };
+  }
+}
+
+function sort(xs, cmp) {
+  let arr = toArray(xs);
+  arr.sort(cmp);
+  return fromArray(arr);
+}
+
+function find(_xs, p) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return;
+    }
+    let x = xs.hd;
+    if (p(x)) {
+      return Primitive_option.some(x);
+    }
+    _xs = xs.tl;
+    continue;
+  };
+}
 
-let concat = flatten;
+function filter(_xs, p) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return /* [] */0;
+    }
+    let t = xs.tl;
+    let h = xs.hd;
+    if (p(h)) {
+      let cell = {
+        hd: h,
+        tl: /* [] */0
+      };
+      copyAuxWitFilter(p, t, cell);
+      return cell;
+    }
+    _xs = t;
+    continue;
+  };
+}
 
-let filter = find_all;
+function filterWithIndex(xs, p) {
+  let _xs = xs;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    let xs$1 = _xs;
+    if (!xs$1) {
+      return /* [] */0;
+    }
+    let t = xs$1.tl;
+    let h = xs$1.hd;
+    if (p(h, i)) {
+      let cell = {
+        hd: h,
+        tl: /* [] */0
+      };
+      copyAuxWithFilterIndex(p, t, cell, i + 1 | 0);
+      return cell;
+    }
+    _i = i + 1 | 0;
+    _xs = t;
+    continue;
+  };
+}
 
-let sort = stable_sort;
+function filterMap(_xs, p) {
+  while (true) {
+    let xs = _xs;
+    if (!xs) {
+      return /* [] */0;
+    }
+    let t = xs.tl;
+    let h = p(xs.hd);
+    if (h !== undefined) {
+      let cell = {
+        hd: Primitive_option.valFromOption(h),
+        tl: /* [] */0
+      };
+      copyAuxWitFilterMap(p, t, cell);
+      return cell;
+    }
+    _xs = t;
+    continue;
+  };
+}
+
+function partition(l, p) {
+  if (!l) {
+    return [
+      /* [] */0,
+      /* [] */0
+    ];
+  }
+  let h = l.hd;
+  let nextX = {
+    hd: h,
+    tl: /* [] */0
+  };
+  let nextY = {
+    hd: h,
+    tl: /* [] */0
+  };
+  let b = p(h);
+  partitionAux(p, l.tl, nextX, nextY);
+  if (b) {
+    return [
+      nextX,
+      nextY.tl
+    ];
+  } else {
+    return [
+      nextX.tl,
+      nextY
+    ];
+  }
+}
+
+function unzip(xs) {
+  if (!xs) {
+    return [
+      /* [] */0,
+      /* [] */0
+    ];
+  }
+  let match = xs.hd;
+  let cellX = {
+    hd: match[0],
+    tl: /* [] */0
+  };
+  let cellY = {
+    hd: match[1],
+    tl: /* [] */0
+  };
+  splitAux(xs.tl, cellX, cellY);
+  return [
+    cellX,
+    cellY
+  ];
+}
+
+function zip(l1, l2) {
+  if (!l1) {
+    return /* [] */0;
+  }
+  if (!l2) {
+    return /* [] */0;
+  }
+  let cell = {
+    hd: [
+      l1.hd,
+      l2.hd
+    ],
+    tl: /* [] */0
+  };
+  zipAux(l1.tl, l2.tl, cell);
+  return cell;
+}
 
-let fast_sort = stable_sort;
+let size = length;
 
 exports.length = length;
-exports.compare_lengths = compare_lengths;
-exports.compare_length_with = compare_length_with;
-exports.cons = cons;
-exports.hd = hd;
-exports.tl = tl;
-exports.nth = nth;
-exports.nth_opt = nth_opt;
-exports.rev = rev;
-exports.init = init;
-exports.append = append;
-exports.rev_append = rev_append;
+exports.size = size;
+exports.head = head;
+exports.headExn = headExn;
+exports.tail = tail;
+exports.tailExn = tailExn;
+exports.add = add;
+exports.get = get;
+exports.getExn = getExn;
+exports.make = make;
+exports.fromInitializer = fromInitializer;
+exports.toShuffled = toShuffled;
+exports.drop = drop;
+exports.take = take;
+exports.splitAt = splitAt;
 exports.concat = concat;
-exports.flatten = flatten;
-exports.iter = iter;
-exports.iteri = iteri;
+exports.concatMany = concatMany;
+exports.reverseConcat = reverseConcat;
+exports.flat = flat;
 exports.map = map;
-exports.mapi = mapi$1;
-exports.rev_map = rev_map;
-exports.fold_left = fold_left;
-exports.fold_right = fold_right;
-exports.iter2 = iter2;
-exports.map2 = map2;
-exports.rev_map2 = rev_map2;
-exports.fold_left2 = fold_left2;
-exports.fold_right2 = fold_right2;
-exports.for_all = for_all;
-exports.exists = exists;
-exports.for_all2 = for_all2;
-exports.exists2 = exists2;
-exports.mem = mem;
-exports.memq = memq;
+exports.zip = zip;
+exports.zipBy = zipBy;
+exports.mapWithIndex = mapWithIndex;
+exports.fromArray = fromArray;
+exports.toArray = toArray;
+exports.reverse = reverse;
+exports.mapReverse = mapReverse;
+exports.forEach = forEach;
+exports.forEachWithIndex = forEachWithIndex;
+exports.reduce = reduce;
+exports.reduceWithIndex = reduceWithIndex;
+exports.reduceReverse = reduceReverse;
+exports.mapReverse2 = mapReverse2;
+exports.forEach2 = forEach2;
+exports.reduce2 = reduce2;
+exports.reduceReverse2 = reduceReverse2;
+exports.every = every;
+exports.some = some;
+exports.every2 = every2;
+exports.some2 = some2;
+exports.compareLength = compareLength;
+exports.compare = compare;
+exports.equal = equal;
+exports.has = has;
 exports.find = find;
-exports.find_opt = find_opt;
 exports.filter = filter;
-exports.find_all = find_all;
+exports.filterWithIndex = filterWithIndex;
+exports.filterMap = filterMap;
 exports.partition = partition;
-exports.assoc = assoc;
-exports.assoc_opt = assoc_opt;
-exports.assq = assq;
-exports.assq_opt = assq_opt;
-exports.mem_assoc = mem_assoc;
-exports.mem_assq = mem_assq;
-exports.remove_assoc = remove_assoc;
-exports.remove_assq = remove_assq;
-exports.split = split;
-exports.combine = combine;
+exports.unzip = unzip;
+exports.getAssoc = getAssoc;
+exports.hasAssoc = hasAssoc;
+exports.removeAssoc = removeAssoc;
+exports.setAssoc = setAssoc;
 exports.sort = sort;
-exports.stable_sort = stable_sort;
-exports.fast_sort = fast_sort;
-exports.sort_uniq = sort_uniq;
-exports.merge = merge;
 /* No side effect */
diff --git a/lib/js/Math.js b/lib/js/Math.js
new file mode 100644
index 0000000000..5d9e3eef7c
--- /dev/null
+++ b/lib/js/Math.js
@@ -0,0 +1,27 @@
+'use strict';
+
+
+let Constants = {};
+
+function floor(f) {
+  return Math.floor(f) | 0;
+}
+
+function ceil(f) {
+  return Math.ceil(f) | 0;
+}
+
+function random(min, max) {
+  let f = Math.random() * (max - min | 0);
+  return (Math.floor(f) | 0) + min | 0;
+}
+
+let Int = {
+  floor: floor,
+  ceil: ceil,
+  random: random
+};
+
+exports.Constants = Constants;
+exports.Int = Int;
+/* No side effect */
diff --git a/lib/js/Null.js b/lib/js/Null.js
new file mode 100644
index 0000000000..d324e36b01
--- /dev/null
+++ b/lib/js/Null.js
@@ -0,0 +1,84 @@
+'use strict';
+
+let Option = require("./Option.js");
+let Primitive_option = require("./Primitive_option.js");
+
+function fromOption(option) {
+  if (option !== undefined) {
+    return Primitive_option.valFromOption(option);
+  }
+  
+}
+
+function equal(a, b, eq) {
+  return Option.equal((a == null) ? undefined : Primitive_option.some(a), (b == null) ? undefined : Primitive_option.some(b), eq);
+}
+
+function compare(a, b, cmp) {
+  return Option.compare((a == null) ? undefined : Primitive_option.some(a), (b == null) ? undefined : Primitive_option.some(b), cmp);
+}
+
+function getOr(value, $$default) {
+  if (value == null) {
+    return $$default;
+  } else {
+    return value;
+  }
+}
+
+function getExn(value) {
+  if (!(value == null)) {
+    return value;
+  }
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Null.getExn: value is null",
+    Error: new Error()
+  };
+}
+
+function forEach(value, f) {
+  if (!(value == null)) {
+    return f(value);
+  }
+  
+}
+
+function map(value, f) {
+  if (!(value == null)) {
+    return f(value);
+  }
+  
+}
+
+function mapOr(value, $$default, f) {
+  if (value == null) {
+    return $$default;
+  } else {
+    return f(value);
+  }
+}
+
+function flatMap(value, f) {
+  if (!(value == null)) {
+    return f(value);
+  }
+  
+}
+
+let getWithDefault = getOr;
+
+let mapWithDefault = mapOr;
+
+exports.equal = equal;
+exports.compare = compare;
+exports.fromOption = fromOption;
+exports.getOr = getOr;
+exports.getWithDefault = getWithDefault;
+exports.getExn = getExn;
+exports.forEach = forEach;
+exports.map = map;
+exports.mapOr = mapOr;
+exports.mapWithDefault = mapWithDefault;
+exports.flatMap = flatMap;
+/* No side effect */
diff --git a/lib/js/Nullable.js b/lib/js/Nullable.js
new file mode 100644
index 0000000000..eeb1eee1fb
--- /dev/null
+++ b/lib/js/Nullable.js
@@ -0,0 +1,86 @@
+'use strict';
+
+let Option = require("./Option.js");
+let Primitive_option = require("./Primitive_option.js");
+
+function fromOption(option) {
+  if (option !== undefined) {
+    return Primitive_option.valFromOption(option);
+  }
+  
+}
+
+function equal(a, b, eq) {
+  return Option.equal(a === null ? undefined : Primitive_option.some(a), b === null ? undefined : Primitive_option.some(b), eq);
+}
+
+function compare(a, b, cmp) {
+  return Option.compare(a === null ? undefined : Primitive_option.some(a), b === null ? undefined : Primitive_option.some(b), cmp);
+}
+
+function getOr(value, $$default) {
+  if (value !== null) {
+    return value;
+  } else {
+    return $$default;
+  }
+}
+
+function getExn(value) {
+  if (value !== null) {
+    return value;
+  }
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Nullable.getExn: value is null or undefined",
+    Error: new Error()
+  };
+}
+
+function forEach(value, f) {
+  if (value !== null) {
+    return f(value);
+  }
+  
+}
+
+function map(value, f) {
+  if (value !== null) {
+    return f(value);
+  } else {
+    return value;
+  }
+}
+
+function mapOr(value, $$default, f) {
+  if (value !== null) {
+    return f(value);
+  } else {
+    return $$default;
+  }
+}
+
+function flatMap(value, f) {
+  if (value !== null) {
+    return f(value);
+  } else {
+    return value;
+  }
+}
+
+let getWithDefault = getOr;
+
+let mapWithDefault = mapOr;
+
+exports.equal = equal;
+exports.compare = compare;
+exports.fromOption = fromOption;
+exports.getOr = getOr;
+exports.getWithDefault = getWithDefault;
+exports.getExn = getExn;
+exports.forEach = forEach;
+exports.map = map;
+exports.mapOr = mapOr;
+exports.mapWithDefault = mapWithDefault;
+exports.flatMap = flatMap;
+/* No side effect */
diff --git a/lib/js/Object.js b/lib/js/Object.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Object.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Option.js b/lib/js/Option.js
new file mode 100644
index 0000000000..221ab3fbba
--- /dev/null
+++ b/lib/js/Option.js
@@ -0,0 +1,118 @@
+'use strict';
+
+let $$Error = require("./Error.js");
+let Primitive_option = require("./Primitive_option.js");
+
+function filter(opt, p) {
+  if (opt !== undefined && p(Primitive_option.valFromOption(opt))) {
+    return opt;
+  }
+  
+}
+
+function forEach(opt, f) {
+  if (opt !== undefined) {
+    return f(Primitive_option.valFromOption(opt));
+  }
+  
+}
+
+function getExn(x, message) {
+  if (x !== undefined) {
+    return Primitive_option.valFromOption(x);
+  } else {
+    return $$Error.panic(message !== undefined ? message : "Option.getExn called for None value");
+  }
+}
+
+function mapOr(opt, $$default, f) {
+  if (opt !== undefined) {
+    return f(Primitive_option.valFromOption(opt));
+  } else {
+    return $$default;
+  }
+}
+
+function map(opt, f) {
+  if (opt !== undefined) {
+    return Primitive_option.some(f(Primitive_option.valFromOption(opt)));
+  }
+  
+}
+
+function flatMap(opt, f) {
+  if (opt !== undefined) {
+    return f(Primitive_option.valFromOption(opt));
+  }
+  
+}
+
+function getOr(opt, $$default) {
+  if (opt !== undefined) {
+    return Primitive_option.valFromOption(opt);
+  } else {
+    return $$default;
+  }
+}
+
+function orElse(opt, other) {
+  if (opt !== undefined) {
+    return opt;
+  } else {
+    return other;
+  }
+}
+
+function isSome(x) {
+  return x !== undefined;
+}
+
+function isNone(x) {
+  return x === undefined;
+}
+
+function equal(a, b, eq) {
+  if (a !== undefined) {
+    if (b !== undefined) {
+      return eq(Primitive_option.valFromOption(a), Primitive_option.valFromOption(b));
+    } else {
+      return false;
+    }
+  } else {
+    return b === undefined;
+  }
+}
+
+function compare(a, b, cmp) {
+  if (a !== undefined) {
+    if (b !== undefined) {
+      return cmp(Primitive_option.valFromOption(a), Primitive_option.valFromOption(b));
+    } else {
+      return 1;
+    }
+  } else if (b !== undefined) {
+    return -1;
+  } else {
+    return 0;
+  }
+}
+
+let mapWithDefault = mapOr;
+
+let getWithDefault = getOr;
+
+exports.filter = filter;
+exports.forEach = forEach;
+exports.getExn = getExn;
+exports.mapOr = mapOr;
+exports.mapWithDefault = mapWithDefault;
+exports.map = map;
+exports.flatMap = flatMap;
+exports.getOr = getOr;
+exports.getWithDefault = getWithDefault;
+exports.orElse = orElse;
+exports.isSome = isSome;
+exports.isNone = isNone;
+exports.equal = equal;
+exports.compare = compare;
+/* No side effect */
diff --git a/lib/js/Ordering.js b/lib/js/Ordering.js
new file mode 100644
index 0000000000..ee7f5ca1ea
--- /dev/null
+++ b/lib/js/Ordering.js
@@ -0,0 +1,35 @@
+'use strict';
+
+
+function isLess(ord) {
+  return ord < 0;
+}
+
+function isEqual(ord) {
+  return ord === 0;
+}
+
+function isGreater(ord) {
+  return ord > 0;
+}
+
+function invert(ord) {
+  return - ord;
+}
+
+function fromInt(n) {
+  if (n < 0) {
+    return -1;
+  } else if (n > 0) {
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+exports.isLess = isLess;
+exports.isEqual = isEqual;
+exports.isGreater = isGreater;
+exports.invert = invert;
+exports.fromInt = fromInt;
+/* No side effect */
diff --git a/lib/js/Pervasives.js b/lib/js/Pervasives.js
index a162ffc7be..fa6d5f7e68 100644
--- a/lib/js/Pervasives.js
+++ b/lib/js/Pervasives.js
@@ -1,5 +1,6 @@
 'use strict';
 
+let $$Error = require("./Error.js");
 let Primitive_exceptions = require("./Primitive_exceptions.js");
 
 function failwith(s) {
@@ -18,7 +19,7 @@ function invalid_arg(s) {
   };
 }
 
-let Exit = /* @__PURE__ */Primitive_exceptions.create("Pervasives.Pervasives.Exit");
+let Exit = /* @__PURE__ */Primitive_exceptions.create("Pervasives.Exit");
 
 function abs(x) {
   if (x >= 0) {
@@ -115,28 +116,6 @@ function $at(l1, l2) {
   }
 }
 
-let Pervasives = {
-  failwith: failwith,
-  invalid_arg: invalid_arg,
-  Exit: Exit,
-  abs: abs,
-  lnot: lnot,
-  max_int: 2147483647,
-  min_int: min_int,
-  infinity: Infinity,
-  neg_infinity: -Infinity,
-  max_float: 1.79769313486231571e+308,
-  min_float: 2.22507385850720138e-308,
-  epsilon_float: 2.22044604925031308e-16,
-  classify_float: classify_float,
-  char_of_int: char_of_int,
-  string_of_bool: string_of_bool,
-  bool_of_string: bool_of_string,
-  bool_of_string_opt: bool_of_string_opt,
-  int_of_string_opt: int_of_string_opt,
-  $at: $at
-};
-
 let max_int = 2147483647;
 
 let infinity = Infinity;
@@ -149,7 +128,8 @@ let min_float = 2.22507385850720138e-308;
 
 let epsilon_float = 2.22044604925031308e-16;
 
-exports.Pervasives = Pervasives;
+let panic = $$Error.panic;
+
 exports.failwith = failwith;
 exports.invalid_arg = invalid_arg;
 exports.Exit = Exit;
@@ -169,4 +149,5 @@ exports.bool_of_string = bool_of_string;
 exports.bool_of_string_opt = bool_of_string_opt;
 exports.int_of_string_opt = int_of_string_opt;
 exports.$at = $at;
+exports.panic = panic;
 /* No side effect */
diff --git a/lib/js/Promise.js b/lib/js/Promise.js
new file mode 100644
index 0000000000..eb6fd42776
--- /dev/null
+++ b/lib/js/Promise.js
@@ -0,0 +1,10 @@
+'use strict';
+
+let Primitive_exceptions = require("./Primitive_exceptions.js");
+
+function $$catch(promise, callback) {
+  return promise.catch(err => callback(Primitive_exceptions.internalToException(err)));
+}
+
+exports.$$catch = $$catch;
+/* No side effect */
diff --git a/lib/js/RegExp.js b/lib/js/RegExp.js
new file mode 100644
index 0000000000..5ce0fbaab3
--- /dev/null
+++ b/lib/js/RegExp.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Result = {};
+
+exports.Result = Result;
+/* No side effect */
diff --git a/lib/js/Result.js b/lib/js/Result.js
new file mode 100644
index 0000000000..d29b38e588
--- /dev/null
+++ b/lib/js/Result.js
@@ -0,0 +1,128 @@
+'use strict';
+
+
+function getExn(x) {
+  if (x.TAG === "Ok") {
+    return x._0;
+  }
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
+}
+
+function mapOr(opt, $$default, f) {
+  if (opt.TAG === "Ok") {
+    return f(opt._0);
+  } else {
+    return $$default;
+  }
+}
+
+function map(opt, f) {
+  if (opt.TAG === "Ok") {
+    return {
+      TAG: "Ok",
+      _0: f(opt._0)
+    };
+  } else {
+    return opt;
+  }
+}
+
+function flatMap(opt, f) {
+  if (opt.TAG === "Ok") {
+    return f(opt._0);
+  } else {
+    return opt;
+  }
+}
+
+function getOr(opt, $$default) {
+  if (opt.TAG === "Ok") {
+    return opt._0;
+  } else {
+    return $$default;
+  }
+}
+
+function isOk(x) {
+  if (x.TAG === "Ok") {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+function isError(x) {
+  if (x.TAG === "Ok") {
+    return false;
+  } else {
+    return true;
+  }
+}
+
+function equal(a, b, f) {
+  if (a.TAG === "Ok") {
+    if (b.TAG === "Ok") {
+      return f(a._0, b._0);
+    } else {
+      return false;
+    }
+  } else if (b.TAG === "Ok") {
+    return false;
+  } else {
+    return true;
+  }
+}
+
+function compare(a, b, f) {
+  if (a.TAG === "Ok") {
+    if (b.TAG === "Ok") {
+      return f(a._0, b._0);
+    } else {
+      return 1;
+    }
+  } else if (b.TAG === "Ok") {
+    return -1;
+  } else {
+    return 0;
+  }
+}
+
+function forEach(r, f) {
+  if (r.TAG === "Ok") {
+    return f(r._0);
+  }
+  
+}
+
+function mapError(r, f) {
+  if (r.TAG === "Ok") {
+    return r;
+  } else {
+    return {
+      TAG: "Error",
+      _0: f(r._0)
+    };
+  }
+}
+
+let mapWithDefault = mapOr;
+
+let getWithDefault = getOr;
+
+exports.getExn = getExn;
+exports.mapOr = mapOr;
+exports.mapWithDefault = mapWithDefault;
+exports.map = map;
+exports.flatMap = flatMap;
+exports.getOr = getOr;
+exports.getWithDefault = getWithDefault;
+exports.isOk = isOk;
+exports.isError = isError;
+exports.equal = equal;
+exports.compare = compare;
+exports.forEach = forEach;
+exports.mapError = mapError;
+/* No side effect */
diff --git a/lib/js/String.js b/lib/js/String.js
index 0ff74c6bc5..b653c67e12 100644
--- a/lib/js/String.js
+++ b/lib/js/String.js
@@ -1,321 +1,31 @@
 'use strict';
 
-let Char = require("./Char.js");
-let $$Array = require("./Array.js");
-let Primitive_exceptions = require("./Primitive_exceptions.js");
 
-function apply1(f, bytes) {
-  if (bytes.length === 0) {
-    return bytes;
+function indexOfOpt(s, search) {
+  let index = s.indexOf(search);
+  if (index !== -1) {
+    return index;
   }
-  let r = bytes.slice();
-  r[0] = f(bytes[0]);
-  return r;
+  
 }
 
-function concat(sep, xs) {
-  return $$Array.of_list(xs).join(sep);
-}
-
-function bos(str) {
-  return $$Array.map(str => str.codePointAt(0), Array.from(str));
-}
-
-function make(len, ch) {
-  return String.fromCodePoint(ch).repeat(len);
-}
-
-function init(len, f) {
-  return $$Array.init(len, i => String.fromCodePoint(f(i))).join("");
-}
-
-function sub(s, ofs, len) {
-  return String.fromCodePoint(...$$Array.sub(bos(s), ofs, len));
-}
-
-function iter(f, s) {
-  for (let i = 0, i_finish = s.length; i < i_finish; ++i) {
-    f(s.codePointAt(i));
-  }
-}
-
-function iteri(f, s) {
-  for (let i = 0, i_finish = s.length; i < i_finish; ++i) {
-    f(i, s.codePointAt(i));
-  }
-}
-
-function map(f, s) {
-  return String.fromCodePoint(...$$Array.map(f, bos(s)));
-}
-
-function mapi(f, s) {
-  return String.fromCodePoint(...$$Array.mapi(f, bos(s)));
-}
-
-function escaped(s) {
-  let needs_escape = _i => {
-    while (true) {
-      let i = _i;
-      if (i >= s.length) {
-        return false;
-      }
-      let match = s.codePointAt(i);
-      if (match < 32) {
-        return true;
-      }
-      if (match > 92 || match < 34) {
-        if (match >= 127) {
-          return true;
-        }
-        _i = i + 1 | 0;
-        continue;
-      }
-      if (match > 91 || match < 35) {
-        return true;
-      }
-      _i = i + 1 | 0;
-      continue;
-    };
-  };
-  if (!needs_escape(0)) {
-    return s;
-  }
-  let bytes = bos(s);
-  return $$Array.map(Char.escaped, bytes).join("");
-}
-
-function index_rec(s, lim, _i, c) {
-  while (true) {
-    let i = _i;
-    if (i >= lim) {
-      throw {
-        RE_EXN_ID: "Not_found",
-        Error: new Error()
-      };
-    }
-    if (s.codePointAt(i) === c) {
-      return i;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
-}
-
-function index(s, c) {
-  return index_rec(s, s.length, 0, c);
-}
-
-function index_rec_opt(s, lim, _i, c) {
-  while (true) {
-    let i = _i;
-    if (i >= lim) {
-      return;
-    }
-    if (s.codePointAt(i) === c) {
-      return i;
-    }
-    _i = i + 1 | 0;
-    continue;
-  };
-}
-
-function index_opt(s, c) {
-  return index_rec_opt(s, s.length, 0, c);
-}
-
-function index_from(s, i, c) {
-  let l = s.length;
-  if (i < 0 || i > l) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.index_from / Bytes.index_from",
-      Error: new Error()
-    };
-  }
-  return index_rec(s, l, i, c);
-}
-
-function index_from_opt(s, i, c) {
-  let l = s.length;
-  if (i < 0 || i > l) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.index_from_opt / Bytes.index_from_opt",
-      Error: new Error()
-    };
+function lastIndexOfOpt(s, search) {
+  let index = s.lastIndexOf(search);
+  if (index !== -1) {
+    return index;
   }
-  return index_rec_opt(s, l, i, c);
-}
-
-function rindex_rec(s, _i, c) {
-  while (true) {
-    let i = _i;
-    if (i < 0) {
-      throw {
-        RE_EXN_ID: "Not_found",
-        Error: new Error()
-      };
-    }
-    if (s.codePointAt(i) === c) {
-      return i;
-    }
-    _i = i - 1 | 0;
-    continue;
-  };
-}
-
-function rindex(s, c) {
-  return rindex_rec(s, s.length - 1 | 0, c);
-}
-
-function rindex_from(s, i, c) {
-  if (i < -1 || i >= s.length) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.rindex_from / Bytes.rindex_from",
-      Error: new Error()
-    };
-  }
-  return rindex_rec(s, i, c);
-}
-
-function rindex_rec_opt(s, _i, c) {
-  while (true) {
-    let i = _i;
-    if (i < 0) {
-      return;
-    }
-    if (s.codePointAt(i) === c) {
-      return i;
-    }
-    _i = i - 1 | 0;
-    continue;
-  };
-}
-
-function rindex_opt(s, c) {
-  return rindex_rec_opt(s, s.length - 1 | 0, c);
-}
-
-function rindex_from_opt(s, i, c) {
-  if (i < -1 || i >= s.length) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
-      Error: new Error()
-    };
-  }
-  return rindex_rec_opt(s, i, c);
-}
-
-function contains_from(s, i, c) {
-  let l = s.length;
-  if (i < 0 || i > l) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.contains_from / Bytes.contains_from",
-      Error: new Error()
-    };
-  }
-  try {
-    index_rec(s, l, i, c);
-    return true;
-  } catch (raw_exn) {
-    let exn = Primitive_exceptions.internalToException(raw_exn);
-    if (exn.RE_EXN_ID === "Not_found") {
-      return false;
-    }
-    throw exn;
-  }
-}
-
-function contains(s, c) {
-  return contains_from(s, 0, c);
-}
-
-function rcontains_from(s, i, c) {
-  if (i < 0 || i >= s.length) {
-    throw {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "String.rcontains_from / Bytes.rcontains_from",
-      Error: new Error()
-    };
-  }
-  try {
-    rindex_rec(s, i, c);
-    return true;
-  } catch (raw_exn) {
-    let exn = Primitive_exceptions.internalToException(raw_exn);
-    if (exn.RE_EXN_ID === "Not_found") {
-      return false;
-    }
-    throw exn;
-  }
-}
-
-function uppercase_ascii(s) {
-  let bytes = bos(s);
-  return String.fromCodePoint(...$$Array.map(Char.uppercase_ascii, bytes));
-}
-
-function lowercase_ascii(s) {
-  let bytes = bos(s);
-  return String.fromCodePoint(...$$Array.map(Char.lowercase_ascii, bytes));
-}
-
-function capitalize_ascii(s) {
-  let bytes = bos(s);
-  return String.fromCodePoint(...apply1(Char.uppercase_ascii, bytes));
-}
-
-function uncapitalize_ascii(s) {
-  let bytes = bos(s);
-  return String.fromCodePoint(...apply1(Char.lowercase_ascii, bytes));
+  
 }
 
-function split_on_char(sep, s) {
-  let r = /* [] */0;
-  let j = s.length;
-  for (let i = s.length - 1 | 0; i >= 0; --i) {
-    if (s.codePointAt(i) === sep) {
-      r = {
-        hd: sub(s, i + 1 | 0, (j - i | 0) - 1 | 0),
-        tl: r
-      };
-      j = i;
-    }
-    
+function searchOpt(s, re) {
+  let index = s.search(re);
+  if (index !== -1) {
+    return index;
   }
-  return {
-    hd: sub(s, 0, j),
-    tl: r
-  };
+  
 }
 
-exports.make = make;
-exports.init = init;
-exports.sub = sub;
-exports.concat = concat;
-exports.iter = iter;
-exports.iteri = iteri;
-exports.map = map;
-exports.mapi = mapi;
-exports.escaped = escaped;
-exports.index = index;
-exports.index_opt = index_opt;
-exports.rindex = rindex;
-exports.rindex_opt = rindex_opt;
-exports.index_from = index_from;
-exports.index_from_opt = index_from_opt;
-exports.rindex_from = rindex_from;
-exports.rindex_from_opt = rindex_from_opt;
-exports.contains = contains;
-exports.contains_from = contains_from;
-exports.rcontains_from = rcontains_from;
-exports.uppercase_ascii = uppercase_ascii;
-exports.lowercase_ascii = lowercase_ascii;
-exports.capitalize_ascii = capitalize_ascii;
-exports.uncapitalize_ascii = uncapitalize_ascii;
-exports.split_on_char = split_on_char;
+exports.indexOfOpt = indexOfOpt;
+exports.lastIndexOfOpt = lastIndexOfOpt;
+exports.searchOpt = searchOpt;
 /* No side effect */
diff --git a/lib/js/Symbol.js b/lib/js/Symbol.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/Symbol.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Type.js b/lib/js/Type.js
new file mode 100644
index 0000000000..97e70a072d
--- /dev/null
+++ b/lib/js/Type.js
@@ -0,0 +1,56 @@
+'use strict';
+
+
+function classify(value) {
+  let match = Object.prototype.toString.call(value);
+  switch (match) {
+    case "[object BigInt]" :
+      return {
+        TAG: "BigInt",
+        _0: value
+      };
+    case "[object Boolean]" :
+      return {
+        TAG: "Bool",
+        _0: value
+      };
+    case "[object AsyncFunction]" :
+    case "[object Function]" :
+    case "[object GeneratorFunction]" :
+      return {
+        TAG: "Function",
+        _0: value
+      };
+    case "[object Null]" :
+      return "Null";
+    case "[object Number]" :
+      return {
+        TAG: "Number",
+        _0: value
+      };
+    case "[object String]" :
+      return {
+        TAG: "String",
+        _0: value
+      };
+    case "[object Symbol]" :
+      return {
+        TAG: "Symbol",
+        _0: value
+      };
+    case "[object Undefined]" :
+      return "Undefined";
+    default:
+      return {
+        TAG: "Object",
+        _0: value
+      };
+  }
+}
+
+let Classify = {
+  classify: classify
+};
+
+exports.Classify = Classify;
+/* No side effect */
diff --git a/lib/js/TypedArray.js b/lib/js/TypedArray.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/TypedArray.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/Uint16Array.js b/lib/js/Uint16Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/Uint16Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/Uint32Array.js b/lib/js/Uint32Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/Uint32Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/Uint8Array.js b/lib/js/Uint8Array.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/Uint8Array.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/Uint8ClampedArray.js b/lib/js/Uint8ClampedArray.js
new file mode 100644
index 0000000000..8ff6f5bdb3
--- /dev/null
+++ b/lib/js/Uint8ClampedArray.js
@@ -0,0 +1,7 @@
+'use strict';
+
+
+let Constants = {};
+
+exports.Constants = Constants;
+/* No side effect */
diff --git a/lib/js/WeakMap.js b/lib/js/WeakMap.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/WeakMap.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/lib/js/WeakSet.js b/lib/js/WeakSet.js
new file mode 100644
index 0000000000..ae1b9f17e6
--- /dev/null
+++ b/lib/js/WeakSet.js
@@ -0,0 +1 @@
+/* This output is empty. Its source's type definitions, externals and/or unused code got optimized away. */
diff --git a/packages/artifacts.txt b/packages/artifacts.txt
index a916707e1c..ac398baaae 100644
--- a/packages/artifacts.txt
+++ b/packages/artifacts.txt
@@ -26,6 +26,8 @@ darwinarm64/rewatch.exe
 docs/docson/build-schema.json
 lib/bstracing
 lib/es6/Array.js
+lib/es6/ArrayBuffer.js
+lib/es6/AsyncIterator.js
 lib/es6/Belt.js
 lib/es6/Belt_Array.js
 lib/es6/Belt_Float.js
@@ -69,11 +71,40 @@ lib/es6/Belt_internalMapString.js
 lib/es6/Belt_internalSetBuckets.js
 lib/es6/Belt_internalSetInt.js
 lib/es6/Belt_internalSetString.js
+lib/es6/BigInt.js
+lib/es6/BigInt64Array.js
+lib/es6/BigUint64Array.js
 lib/es6/Char.js
+lib/es6/Console.js
+lib/es6/DataView.js
+lib/es6/Date.js
+lib/es6/Dict.js
 lib/es6/Dom.js
 lib/es6/Dom_storage.js
 lib/es6/Dom_storage2.js
-lib/es6/Hashtbl.js
+lib/es6/Error.js
+lib/es6/Exn.js
+lib/es6/Float.js
+lib/es6/Float32Array.js
+lib/es6/Float64Array.js
+lib/es6/Int.js
+lib/es6/Int16Array.js
+lib/es6/Int32Array.js
+lib/es6/Int8Array.js
+lib/es6/Intl.js
+lib/es6/Intl_Collator.js
+lib/es6/Intl_Common.js
+lib/es6/Intl_DateTimeFormat.js
+lib/es6/Intl_ListFormat.js
+lib/es6/Intl_Locale.js
+lib/es6/Intl_NumberFormat.js
+lib/es6/Intl_NumberFormat_Grouping.js
+lib/es6/Intl_PluralRules.js
+lib/es6/Intl_RelativeTimeFormat.js
+lib/es6/Intl_Segmenter.js
+lib/es6/Intl_Segments.js
+lib/es6/Iterator.js
+lib/es6/JSON.js
 lib/es6/Js.js
 lib/es6/Js_OO.js
 lib/es6/Js_array.js
@@ -83,7 +114,6 @@ lib/es6/Js_blob.js
 lib/es6/Js_console.js
 lib/es6/Js_date.js
 lib/es6/Js_dict.js
-lib/es6/Js_exn.js
 lib/es6/Js_extern.js
 lib/es6/Js_file.js
 lib/es6/Js_float.js
@@ -117,7 +147,13 @@ lib/es6/JsxPPXReactSupport.js
 lib/es6/Lazy.js
 lib/es6/List.js
 lib/es6/Map.js
+lib/es6/Math.js
+lib/es6/Null.js
+lib/es6/Nullable.js
 lib/es6/Obj.js
+lib/es6/Object.js
+lib/es6/Option.js
+lib/es6/Ordering.js
 lib/es6/Pervasives.js
 lib/es6/Primitive_array.js
 lib/es6/Primitive_array_extern.js
@@ -142,10 +178,24 @@ lib/es6/Primitive_promise.js
 lib/es6/Primitive_string.js
 lib/es6/Primitive_string_extern.js
 lib/es6/Primitive_util.js
+lib/es6/Promise.js
+lib/es6/RegExp.js
+lib/es6/Result.js
 lib/es6/Set.js
 lib/es6/String.js
+lib/es6/Symbol.js
+lib/es6/Type.js
+lib/es6/TypedArray.js
+lib/es6/Uint16Array.js
+lib/es6/Uint32Array.js
+lib/es6/Uint8Array.js
+lib/es6/Uint8ClampedArray.js
+lib/es6/WeakMap.js
+lib/es6/WeakSet.js
 lib/es6/package.json
 lib/js/Array.js
+lib/js/ArrayBuffer.js
+lib/js/AsyncIterator.js
 lib/js/Belt.js
 lib/js/Belt_Array.js
 lib/js/Belt_Float.js
@@ -189,11 +239,40 @@ lib/js/Belt_internalMapString.js
 lib/js/Belt_internalSetBuckets.js
 lib/js/Belt_internalSetInt.js
 lib/js/Belt_internalSetString.js
+lib/js/BigInt.js
+lib/js/BigInt64Array.js
+lib/js/BigUint64Array.js
 lib/js/Char.js
+lib/js/Console.js
+lib/js/DataView.js
+lib/js/Date.js
+lib/js/Dict.js
 lib/js/Dom.js
 lib/js/Dom_storage.js
 lib/js/Dom_storage2.js
-lib/js/Hashtbl.js
+lib/js/Error.js
+lib/js/Exn.js
+lib/js/Float.js
+lib/js/Float32Array.js
+lib/js/Float64Array.js
+lib/js/Int.js
+lib/js/Int16Array.js
+lib/js/Int32Array.js
+lib/js/Int8Array.js
+lib/js/Intl.js
+lib/js/Intl_Collator.js
+lib/js/Intl_Common.js
+lib/js/Intl_DateTimeFormat.js
+lib/js/Intl_ListFormat.js
+lib/js/Intl_Locale.js
+lib/js/Intl_NumberFormat.js
+lib/js/Intl_NumberFormat_Grouping.js
+lib/js/Intl_PluralRules.js
+lib/js/Intl_RelativeTimeFormat.js
+lib/js/Intl_Segmenter.js
+lib/js/Intl_Segments.js
+lib/js/Iterator.js
+lib/js/JSON.js
 lib/js/Js.js
 lib/js/Js_OO.js
 lib/js/Js_array.js
@@ -203,7 +282,6 @@ lib/js/Js_blob.js
 lib/js/Js_console.js
 lib/js/Js_date.js
 lib/js/Js_dict.js
-lib/js/Js_exn.js
 lib/js/Js_extern.js
 lib/js/Js_file.js
 lib/js/Js_float.js
@@ -237,7 +315,13 @@ lib/js/JsxPPXReactSupport.js
 lib/js/Lazy.js
 lib/js/List.js
 lib/js/Map.js
+lib/js/Math.js
+lib/js/Null.js
+lib/js/Nullable.js
 lib/js/Obj.js
+lib/js/Object.js
+lib/js/Option.js
+lib/js/Ordering.js
 lib/js/Pervasives.js
 lib/js/Primitive_array.js
 lib/js/Primitive_array_extern.js
@@ -262,8 +346,20 @@ lib/js/Primitive_promise.js
 lib/js/Primitive_string.js
 lib/js/Primitive_string_extern.js
 lib/js/Primitive_util.js
+lib/js/Promise.js
+lib/js/RegExp.js
+lib/js/Result.js
 lib/js/Set.js
 lib/js/String.js
+lib/js/Symbol.js
+lib/js/Type.js
+lib/js/TypedArray.js
+lib/js/Uint16Array.js
+lib/js/Uint32Array.js
+lib/js/Uint8Array.js
+lib/js/Uint8ClampedArray.js
+lib/js/WeakMap.js
+lib/js/WeakSet.js
 lib/minisocket.js
 lib/ocaml/Array.cmi
 lib/ocaml/Array.cmj
@@ -271,6 +367,16 @@ lib/ocaml/Array.cmt
 lib/ocaml/Array.cmti
 lib/ocaml/Array.res
 lib/ocaml/Array.resi
+lib/ocaml/ArrayBuffer.cmi
+lib/ocaml/ArrayBuffer.cmj
+lib/ocaml/ArrayBuffer.cmt
+lib/ocaml/ArrayBuffer.res
+lib/ocaml/AsyncIterator.cmi
+lib/ocaml/AsyncIterator.cmj
+lib/ocaml/AsyncIterator.cmt
+lib/ocaml/AsyncIterator.cmti
+lib/ocaml/AsyncIterator.res
+lib/ocaml/AsyncIterator.resi
 lib/ocaml/Belt.cmi
 lib/ocaml/Belt.cmj
 lib/ocaml/Belt.cmt
@@ -519,12 +625,46 @@ lib/ocaml/Belt_internalSetString.cmi
 lib/ocaml/Belt_internalSetString.cmj
 lib/ocaml/Belt_internalSetString.cmt
 lib/ocaml/Belt_internalSetString.res
+lib/ocaml/BigInt.cmi
+lib/ocaml/BigInt.cmj
+lib/ocaml/BigInt.cmt
+lib/ocaml/BigInt.res
+lib/ocaml/BigInt64Array.cmi
+lib/ocaml/BigInt64Array.cmj
+lib/ocaml/BigInt64Array.cmt
+lib/ocaml/BigInt64Array.res
+lib/ocaml/BigUint64Array.cmi
+lib/ocaml/BigUint64Array.cmj
+lib/ocaml/BigUint64Array.cmt
+lib/ocaml/BigUint64Array.res
 lib/ocaml/Char.cmi
 lib/ocaml/Char.cmj
 lib/ocaml/Char.cmt
 lib/ocaml/Char.cmti
 lib/ocaml/Char.res
 lib/ocaml/Char.resi
+lib/ocaml/Console.cmi
+lib/ocaml/Console.cmj
+lib/ocaml/Console.cmt
+lib/ocaml/Console.cmti
+lib/ocaml/Console.res
+lib/ocaml/Console.resi
+lib/ocaml/DataView.cmi
+lib/ocaml/DataView.cmj
+lib/ocaml/DataView.cmt
+lib/ocaml/DataView.res
+lib/ocaml/Date.cmi
+lib/ocaml/Date.cmj
+lib/ocaml/Date.cmt
+lib/ocaml/Date.cmti
+lib/ocaml/Date.res
+lib/ocaml/Date.resi
+lib/ocaml/Dict.cmi
+lib/ocaml/Dict.cmj
+lib/ocaml/Dict.cmt
+lib/ocaml/Dict.cmti
+lib/ocaml/Dict.res
+lib/ocaml/Dict.resi
 lib/ocaml/Dom.cmi
 lib/ocaml/Dom.cmj
 lib/ocaml/Dom.cmt
@@ -537,12 +677,110 @@ lib/ocaml/Dom_storage2.cmi
 lib/ocaml/Dom_storage2.cmj
 lib/ocaml/Dom_storage2.cmt
 lib/ocaml/Dom_storage2.res
-lib/ocaml/Hashtbl.cmi
-lib/ocaml/Hashtbl.cmj
-lib/ocaml/Hashtbl.cmt
-lib/ocaml/Hashtbl.cmti
-lib/ocaml/Hashtbl.res
-lib/ocaml/Hashtbl.resi
+lib/ocaml/Error.cmi
+lib/ocaml/Error.cmj
+lib/ocaml/Error.cmt
+lib/ocaml/Error.cmti
+lib/ocaml/Error.res
+lib/ocaml/Error.resi
+lib/ocaml/Exn.cmi
+lib/ocaml/Exn.cmj
+lib/ocaml/Exn.cmt
+lib/ocaml/Exn.cmti
+lib/ocaml/Exn.res
+lib/ocaml/Exn.resi
+lib/ocaml/Float.cmi
+lib/ocaml/Float.cmj
+lib/ocaml/Float.cmt
+lib/ocaml/Float.cmti
+lib/ocaml/Float.res
+lib/ocaml/Float.resi
+lib/ocaml/Float32Array.cmi
+lib/ocaml/Float32Array.cmj
+lib/ocaml/Float32Array.cmt
+lib/ocaml/Float32Array.res
+lib/ocaml/Float64Array.cmi
+lib/ocaml/Float64Array.cmj
+lib/ocaml/Float64Array.cmt
+lib/ocaml/Float64Array.res
+lib/ocaml/Int.cmi
+lib/ocaml/Int.cmj
+lib/ocaml/Int.cmt
+lib/ocaml/Int.cmti
+lib/ocaml/Int.res
+lib/ocaml/Int.resi
+lib/ocaml/Int16Array.cmi
+lib/ocaml/Int16Array.cmj
+lib/ocaml/Int16Array.cmt
+lib/ocaml/Int16Array.res
+lib/ocaml/Int32Array.cmi
+lib/ocaml/Int32Array.cmj
+lib/ocaml/Int32Array.cmt
+lib/ocaml/Int32Array.res
+lib/ocaml/Int8Array.cmi
+lib/ocaml/Int8Array.cmj
+lib/ocaml/Int8Array.cmt
+lib/ocaml/Int8Array.res
+lib/ocaml/Intl.cmi
+lib/ocaml/Intl.cmj
+lib/ocaml/Intl.cmt
+lib/ocaml/Intl.res
+lib/ocaml/Intl_Collator.cmi
+lib/ocaml/Intl_Collator.cmj
+lib/ocaml/Intl_Collator.cmt
+lib/ocaml/Intl_Collator.res
+lib/ocaml/Intl_Common.cmi
+lib/ocaml/Intl_Common.cmj
+lib/ocaml/Intl_Common.cmt
+lib/ocaml/Intl_Common.res
+lib/ocaml/Intl_DateTimeFormat.cmi
+lib/ocaml/Intl_DateTimeFormat.cmj
+lib/ocaml/Intl_DateTimeFormat.cmt
+lib/ocaml/Intl_DateTimeFormat.res
+lib/ocaml/Intl_ListFormat.cmi
+lib/ocaml/Intl_ListFormat.cmj
+lib/ocaml/Intl_ListFormat.cmt
+lib/ocaml/Intl_ListFormat.res
+lib/ocaml/Intl_Locale.cmi
+lib/ocaml/Intl_Locale.cmj
+lib/ocaml/Intl_Locale.cmt
+lib/ocaml/Intl_Locale.res
+lib/ocaml/Intl_NumberFormat.cmi
+lib/ocaml/Intl_NumberFormat.cmj
+lib/ocaml/Intl_NumberFormat.cmt
+lib/ocaml/Intl_NumberFormat.res
+lib/ocaml/Intl_NumberFormat_Grouping.cmi
+lib/ocaml/Intl_NumberFormat_Grouping.cmj
+lib/ocaml/Intl_NumberFormat_Grouping.cmt
+lib/ocaml/Intl_NumberFormat_Grouping.res
+lib/ocaml/Intl_PluralRules.cmi
+lib/ocaml/Intl_PluralRules.cmj
+lib/ocaml/Intl_PluralRules.cmt
+lib/ocaml/Intl_PluralRules.res
+lib/ocaml/Intl_RelativeTimeFormat.cmi
+lib/ocaml/Intl_RelativeTimeFormat.cmj
+lib/ocaml/Intl_RelativeTimeFormat.cmt
+lib/ocaml/Intl_RelativeTimeFormat.res
+lib/ocaml/Intl_Segmenter.cmi
+lib/ocaml/Intl_Segmenter.cmj
+lib/ocaml/Intl_Segmenter.cmt
+lib/ocaml/Intl_Segmenter.res
+lib/ocaml/Intl_Segments.cmi
+lib/ocaml/Intl_Segments.cmj
+lib/ocaml/Intl_Segments.cmt
+lib/ocaml/Intl_Segments.res
+lib/ocaml/Iterator.cmi
+lib/ocaml/Iterator.cmj
+lib/ocaml/Iterator.cmt
+lib/ocaml/Iterator.cmti
+lib/ocaml/Iterator.res
+lib/ocaml/Iterator.resi
+lib/ocaml/JSON.cmi
+lib/ocaml/JSON.cmj
+lib/ocaml/JSON.cmt
+lib/ocaml/JSON.cmti
+lib/ocaml/JSON.res
+lib/ocaml/JSON.resi
 lib/ocaml/Js.cmi
 lib/ocaml/Js.cmj
 lib/ocaml/Js.cmt
@@ -581,12 +819,6 @@ lib/ocaml/Js_dict.cmt
 lib/ocaml/Js_dict.cmti
 lib/ocaml/Js_dict.res
 lib/ocaml/Js_dict.resi
-lib/ocaml/Js_exn.cmi
-lib/ocaml/Js_exn.cmj
-lib/ocaml/Js_exn.cmt
-lib/ocaml/Js_exn.cmti
-lib/ocaml/Js_exn.res
-lib/ocaml/Js_exn.resi
 lib/ocaml/Js_extern.cmi
 lib/ocaml/Js_extern.cmj
 lib/ocaml/Js_extern.cmt
@@ -736,11 +968,45 @@ lib/ocaml/List.resi
 lib/ocaml/Map.cmi
 lib/ocaml/Map.cmj
 lib/ocaml/Map.cmt
+lib/ocaml/Map.cmti
 lib/ocaml/Map.res
+lib/ocaml/Map.resi
+lib/ocaml/Math.cmi
+lib/ocaml/Math.cmj
+lib/ocaml/Math.cmt
+lib/ocaml/Math.cmti
+lib/ocaml/Math.res
+lib/ocaml/Math.resi
+lib/ocaml/Null.cmi
+lib/ocaml/Null.cmj
+lib/ocaml/Null.cmt
+lib/ocaml/Null.cmti
+lib/ocaml/Null.res
+lib/ocaml/Null.resi
+lib/ocaml/Nullable.cmi
+lib/ocaml/Nullable.cmj
+lib/ocaml/Nullable.cmt
+lib/ocaml/Nullable.cmti
+lib/ocaml/Nullable.res
+lib/ocaml/Nullable.resi
 lib/ocaml/Obj.cmi
 lib/ocaml/Obj.cmj
 lib/ocaml/Obj.cmt
 lib/ocaml/Obj.res
+lib/ocaml/Object.cmi
+lib/ocaml/Object.cmj
+lib/ocaml/Object.cmt
+lib/ocaml/Object.res
+lib/ocaml/Option.cmi
+lib/ocaml/Option.cmj
+lib/ocaml/Option.cmt
+lib/ocaml/Option.cmti
+lib/ocaml/Option.res
+lib/ocaml/Option.resi
+lib/ocaml/Ordering.cmi
+lib/ocaml/Ordering.cmj
+lib/ocaml/Ordering.cmt
+lib/ocaml/Ordering.res
 lib/ocaml/Pervasives.cmi
 lib/ocaml/Pervasives.cmj
 lib/ocaml/Pervasives.cmt
@@ -851,16 +1117,74 @@ lib/ocaml/Primitive_util.cmi
 lib/ocaml/Primitive_util.cmj
 lib/ocaml/Primitive_util.cmt
 lib/ocaml/Primitive_util.res
+lib/ocaml/Promise.cmi
+lib/ocaml/Promise.cmj
+lib/ocaml/Promise.cmt
+lib/ocaml/Promise.cmti
+lib/ocaml/Promise.res
+lib/ocaml/Promise.resi
+lib/ocaml/RegExp.cmi
+lib/ocaml/RegExp.cmj
+lib/ocaml/RegExp.cmt
+lib/ocaml/RegExp.cmti
+lib/ocaml/RegExp.res
+lib/ocaml/RegExp.resi
+lib/ocaml/Result.cmi
+lib/ocaml/Result.cmj
+lib/ocaml/Result.cmt
+lib/ocaml/Result.cmti
+lib/ocaml/Result.res
+lib/ocaml/Result.resi
 lib/ocaml/Set.cmi
 lib/ocaml/Set.cmj
 lib/ocaml/Set.cmt
+lib/ocaml/Set.cmti
 lib/ocaml/Set.res
+lib/ocaml/Set.resi
 lib/ocaml/String.cmi
 lib/ocaml/String.cmj
 lib/ocaml/String.cmt
 lib/ocaml/String.cmti
 lib/ocaml/String.res
 lib/ocaml/String.resi
+lib/ocaml/Symbol.cmi
+lib/ocaml/Symbol.cmj
+lib/ocaml/Symbol.cmt
+lib/ocaml/Symbol.res
+lib/ocaml/Type.cmi
+lib/ocaml/Type.cmj
+lib/ocaml/Type.cmt
+lib/ocaml/Type.cmti
+lib/ocaml/Type.res
+lib/ocaml/Type.resi
+lib/ocaml/TypedArray.cmi
+lib/ocaml/TypedArray.cmj
+lib/ocaml/TypedArray.cmt
+lib/ocaml/TypedArray.res
+lib/ocaml/Uint16Array.cmi
+lib/ocaml/Uint16Array.cmj
+lib/ocaml/Uint16Array.cmt
+lib/ocaml/Uint16Array.res
+lib/ocaml/Uint32Array.cmi
+lib/ocaml/Uint32Array.cmj
+lib/ocaml/Uint32Array.cmt
+lib/ocaml/Uint32Array.res
+lib/ocaml/Uint8Array.cmi
+lib/ocaml/Uint8Array.cmj
+lib/ocaml/Uint8Array.cmt
+lib/ocaml/Uint8Array.res
+lib/ocaml/Uint8ClampedArray.cmi
+lib/ocaml/Uint8ClampedArray.cmj
+lib/ocaml/Uint8ClampedArray.cmt
+lib/ocaml/Uint8ClampedArray.res
+lib/ocaml/WeakMap.cmi
+lib/ocaml/WeakMap.cmj
+lib/ocaml/WeakMap.cmt
+lib/ocaml/WeakMap.res
+lib/ocaml/WeakSet.cmi
+lib/ocaml/WeakSet.cmj
+lib/ocaml/WeakSet.cmt
+lib/ocaml/WeakSet.res
 linux/bsb_helper.exe
 linux/bsc.exe
 linux/ninja.exe
diff --git a/packages/playground-bundling/package-lock.json b/packages/playground-bundling/package-lock.json
index 6d7f57dac6..85a1ed5159 100644
--- a/packages/playground-bundling/package-lock.json
+++ b/packages/playground-bundling/package-lock.json
@@ -9,18 +9,9 @@
       "version": "1.0.0",
       "license": "ISC",
       "dependencies": {
-        "@rescript/core": "^1.5.2",
         "@rescript/react": "^0.13.0"
       }
     },
-    "node_modules/@rescript/core": {
-      "version": "1.5.2",
-      "resolved": "https://registry.npmjs.org/@rescript/core/-/core-1.5.2.tgz",
-      "integrity": "sha512-VWRFHrQu8hWnd9Y9LYZ8kig2urybhZlDVGy5u50bqf2WCRAeysBIfxK8eN4VlpQT38igMo0/uLX1KSpwCVMYGw==",
-      "peerDependencies": {
-        "rescript": "^11.1.0-rc.7"
-      }
-    },
     "node_modules/@rescript/react": {
       "version": "0.13.0",
       "resolved": "https://registry.npmjs.org/@rescript/react/-/react-0.13.0.tgz",
@@ -73,21 +64,6 @@
         "react": "^18.2.0"
       }
     },
-    "node_modules/rescript": {
-      "version": "11.1.1",
-      "resolved": "https://registry.npmjs.org/rescript/-/rescript-11.1.1.tgz",
-      "integrity": "sha512-FMELeoiR1n3LzBdBt+k7U4l0vsz5Xh0HBSHf+0NhyhzZkMRLkEKEDNrcqZc6RIux9bxmxoO+zEa9qFM01VOXAw==",
-      "hasInstallScript": true,
-      "peer": true,
-      "bin": {
-        "bsc": "bsc",
-        "bstracing": "lib/bstracing",
-        "rescript": "rescript"
-      },
-      "engines": {
-        "node": ">=10"
-      }
-    },
     "node_modules/scheduler": {
       "version": "0.23.0",
       "resolved": "https://registry.npmjs.org/scheduler/-/scheduler-0.23.0.tgz",
@@ -99,12 +75,6 @@
     }
   },
   "dependencies": {
-    "@rescript/core": {
-      "version": "1.5.2",
-      "resolved": "https://registry.npmjs.org/@rescript/core/-/core-1.5.2.tgz",
-      "integrity": "sha512-VWRFHrQu8hWnd9Y9LYZ8kig2urybhZlDVGy5u50bqf2WCRAeysBIfxK8eN4VlpQT38igMo0/uLX1KSpwCVMYGw==",
-      "requires": {}
-    },
     "@rescript/react": {
       "version": "0.13.0",
       "resolved": "https://registry.npmjs.org/@rescript/react/-/react-0.13.0.tgz",
@@ -145,12 +115,6 @@
         "scheduler": "^0.23.0"
       }
     },
-    "rescript": {
-      "version": "11.1.1",
-      "resolved": "https://registry.npmjs.org/rescript/-/rescript-11.1.1.tgz",
-      "integrity": "sha512-FMELeoiR1n3LzBdBt+k7U4l0vsz5Xh0HBSHf+0NhyhzZkMRLkEKEDNrcqZc6RIux9bxmxoO+zEa9qFM01VOXAw==",
-      "peer": true
-    },
     "scheduler": {
       "version": "0.23.0",
       "resolved": "https://registry.npmjs.org/scheduler/-/scheduler-0.23.0.tgz",
diff --git a/packages/playground-bundling/package.json b/packages/playground-bundling/package.json
index bdc31fb0df..59780359ca 100644
--- a/packages/playground-bundling/package.json
+++ b/packages/playground-bundling/package.json
@@ -11,7 +11,6 @@
   "author": "",
   "license": "ISC",
   "dependencies": {
-    "@rescript/core": "^1.5.2",
     "@rescript/react": "^0.13.0"
   }
 }
diff --git a/packages/playground-bundling/rescript.json b/packages/playground-bundling/rescript.json
index bb00f330c9..5f53495101 100644
--- a/packages/playground-bundling/rescript.json
+++ b/packages/playground-bundling/rescript.json
@@ -1,7 +1,7 @@
 {
   "name": "playground",
   "version": "0.1.0",
-  "bs-dependencies": ["@rescript/react", "@rescript/core"],
+  "bs-dependencies": ["@rescript/react"],
   "package-specs": {
     "module": "esmodule",
     "in-source": false
diff --git a/playground/playground_test.js b/playground/playground_test.js
index 62fefcc180..98807109cf 100644
--- a/playground/playground_test.js
+++ b/playground/playground_test.js
@@ -1,12 +1,9 @@
 require("./compiler.js")
 require("./packages/compiler-builtins/cmij.js")
 require("./packages/@rescript/react/cmij.js")
-require("./packages/@rescript/core/cmij.js")
 
 let compiler = rescript_compiler.make()
 
-compiler.setOpenModules(["RescriptCore"])
-
 let result = compiler.rescript.compile(`
   @@jsxConfig({ version: 4, mode: "automatic" })
 
diff --git a/playground/upload_bundle.sh b/playground/upload_bundle.sh
index 99a9c64593..135b0ba29f 100755
--- a/playground/upload_bundle.sh
+++ b/playground/upload_bundle.sh
@@ -29,7 +29,7 @@ if [ ! -f "${NETRC_FILE}" ]; then
   echo "machine ${KEYCDN_SRV} login $KEYCDN_USER password $KEYCDN_PASSWORD" > "${NETRC_FILE}"
 fi
 
-PACKAGES=("compiler-builtins" "@rescript/react" "@rescript/core")
+PACKAGES=("compiler-builtins" "@rescript/react")
 
 echo "Uploading compiler.js file..."
 curl --ftp-create-dirs -T "${SCRIPT_DIR}/compiler.js" --ssl --netrc-file $NETRC_FILE ftp://${KEYCDN_SRV}/v${VERSION}/compiler.js
diff --git a/runtime/Array.res b/runtime/Array.res
index 6339770b3a..23ff2dc7b1 100644
--- a/runtime/Array.res
+++ b/runtime/Array.res
@@ -1,383 +1,269 @@
-// FIXME:
-//   This exists for compatibility reason.
-//   Move this into Pervasives or Core
-
-// Caution: `Array.get` is implicitly used by `array[idx]` syntax
-external get: (array<'a>, int) => 'a = "%array_safe_get"
-
-// Caution: `Array.set` is implicitly used by `array[idx]` syntax
-external set: (array<'a>, int, 'a) => unit = "%array_safe_set"
-
-// Below is all deprecated and should be removed in v13
-
-external length: array<'a> => int = "%array_length"
+@new external makeUninitializedUnsafe: int => array<'a> = "Array"
+@set external truncateToLengthUnsafe: (array<'a>, int) => unit = "length"
+external getUnsafe: (array<'a>, int) => 'a = "%array_unsafe_get"
+external setUnsafe: (array<'a>, int, 'a) => unit = "%array_unsafe_set"
 
 external unsafe_get: (array<'a>, int) => 'a = "%array_unsafe_get"
 
-external unsafe_set: (array<'a>, int, 'a) => unit = "%array_unsafe_set"
-
-let init: (int, int => 'a) => array<'a> = %raw(`(length, f) => Array.from({ length }, f)`)
-
-let make = (len, x) => init(len, _ => x)
-
-@send external slice: (array<'a>, int, int) => array<'a> = "slice"
-let unsafe_sub = (array, offset, length) => array->slice(offset, offset + length)
-
-@send external concat: (array<'a>, array<'a>) => array<'a> = "concat"
-@send external append_prim: (array<'a>, array<'a>) => array<'a> = "concat"
-
-let concat = list => {
-  List.fold_left((arr1, arr2) => arr1->concat(arr2), [], list)
-}
-
-let unsafe_blit = (srcArray, srcOffset, destArray, destOffset, len) => {
-  for i in 0 to len - 1 {
-    destArray->unsafe_set(destOffset + i, srcArray->unsafe_get(srcOffset + i))
-  }
-}
-
-let create_float = len => make(len, 0.0)
+@val external fromIterator: Iterator.t<'a> => array<'a> = "Array.from"
+@val external fromArrayLike: Js.Array2.array_like<'a> => array<'a> = "Array.from"
+@val
+external fromArrayLikeWithMap: (Js.Array2.array_like<'a>, 'a => 'b) => array<'b> = "Array.from"
 
-let make_matrix = (sx, sy, init) => {
-  let res = make(sx, [])
-  for x in 0 to pred(sx) {
-    unsafe_set(res, x, make(sy, init))
-  }
-  res
-}
+@send external fillAll: (array<'a>, 'a) => unit = "fill"
 
-@send external copy: array<'a> => array<'a> = "slice"
+@send external fillToEnd: (array<'a>, 'a, ~start: int) => unit = "fill"
 
-let append = (a1, a2) => {
-  let l1 = length(a1)
-  if l1 == 0 {
-    copy(a2)
-  } else if length(a2) == 0 {
-    unsafe_sub(a1, 0, l1)
-  } else {
-    append_prim(a1, a2)
-  }
-}
+@send external fill: (array<'a>, 'a, ~start: int, ~end: int) => unit = "fill"
 
-let sub = (a, ofs, len) =>
-  if ofs < 0 || (len < 0 || ofs > length(a) - len) {
-    invalid_arg("Array.sub")
+let make = (~length, x) =>
+  if length <= 0 {
+    []
   } else {
-    unsafe_sub(a, ofs, len)
+    let arr = makeUninitializedUnsafe(length)
+    arr->fillAll(x)
+    arr
   }
 
-let fill = (a, ofs, len, v) =>
-  if ofs < 0 || (len < 0 || ofs > length(a) - len) {
-    invalid_arg("Array.fill")
+let fromInitializer = (~length, f) =>
+  if length <= 0 {
+    []
   } else {
-    for i in ofs to ofs + len - 1 {
-      unsafe_set(a, i, v)
+    let arr = makeUninitializedUnsafe(length)
+    for i in 0 to length - 1 {
+      arr->setUnsafe(i, f(i))
     }
+    arr
   }
 
-let blit = (a1, ofs1, a2, ofs2, len) =>
-  if len < 0 || (ofs1 < 0 || (ofs1 > length(a1) - len || (ofs2 < 0 || ofs2 > length(a2) - len))) {
-    invalid_arg("Array.blit")
-  } else {
-    unsafe_blit(a1, ofs1, a2, ofs2, len)
-  }
+@val external isArray: 'a => bool = "Array.isArray"
 
-let iter = (f, a) =>
-  for i in 0 to length(a) - 1 {
-    f(unsafe_get(a, i))
-  }
+@get external length: array<'a> => int = "length"
 
-let iter2 = (f, a, b) =>
-  if length(a) != length(b) {
-    invalid_arg("Array.iter2: arrays must have the same length")
+let rec equalFromIndex = (a, b, i, eq, len) =>
+  if i === len {
+    true
+  } else if eq(a->getUnsafe(i), b->getUnsafe(i)) {
+    equalFromIndex(a, b, i + 1, eq, len)
   } else {
-    for i in 0 to length(a) - 1 {
-      f(unsafe_get(a, i), unsafe_get(b, i))
-    }
+    false
   }
 
-let map = (f, a) => {
-  let l = length(a)
-  if l == 0 {
-    []
+let equal = (a, b, eq) => {
+  let len = a->length
+  if len === b->length {
+    equalFromIndex(a, b, 0, eq, len)
   } else {
-    let r = make(l, f(unsafe_get(a, 0)))
-    for i in 1 to l - 1 {
-      unsafe_set(r, i, f(unsafe_get(a, i)))
-    }
-    r
+    false
   }
 }
 
-let map2 = (f, a, b) => {
-  let la = length(a)
-  let lb = length(b)
-  if la != lb {
-    invalid_arg("Array.map2: arrays must have the same length")
-  } else if la == 0 {
-    []
+let rec compareFromIndex = (a, b, i, cmp, len) =>
+  if i === len {
+    Ordering.equal
   } else {
-    let r = make(la, f(unsafe_get(a, 0), unsafe_get(b, 0)))
-    for i in 1 to la - 1 {
-      unsafe_set(r, i, f(unsafe_get(a, i), unsafe_get(b, i)))
+    let c = cmp(a->getUnsafe(i), b->getUnsafe(i))
+    if c == Ordering.equal {
+      compareFromIndex(a, b, i + 1, cmp, len)
+    } else {
+      c
     }
-    r
   }
+
+let compare = (a, b, cmp) => {
+  let lenA = a->length
+  let lenB = b->length
+  lenA < lenB
+    ? Ordering.less
+    : lenA > lenB
+    ? Ordering.greater
+    : compareFromIndex(a, b, 0, cmp, lenA)
 }
 
-let iteri = (f, a) =>
-  for i in 0 to length(a) - 1 {
-    f(i, unsafe_get(a, i))
-  }
+@send external copyAllWithin: (array<'a>, ~target: int) => array<'a> = "copyWithin"
 
-let mapi = (f, a) => {
-  let l = length(a)
-  if l == 0 {
-    []
-  } else {
-    let r = make(l, f(0, unsafe_get(a, 0)))
-    for i in 1 to l - 1 {
-      unsafe_set(r, i, f(i, unsafe_get(a, i)))
-    }
-    r
-  }
-}
+@send
+external copyWithinToEnd: (array<'a>, ~target: int, ~start: int) => array<'a> = "copyWithin"
 
-let to_list = a => {
-  let rec tolist = (i, res) =>
-    if i < 0 {
-      res
-    } else {
-      tolist(i - 1, list{unsafe_get(a, i), ...res})
-    }
-  tolist(length(a) - 1, list{})
-}
+@send
+external copyWithin: (array<'a>, ~target: int, ~start: int, ~end: int) => array<'a> = "copyWithin"
 
-/* Cannot use List.length here because the List module depends on Array. */
-let rec list_length = (accu, param) =>
-  switch param {
-  | list{} => accu
-  | list{_, ...t} => list_length(succ(accu), t)
-  }
+@send external pop: array<'a> => option<'a> = "pop"
 
-let of_list = param =>
-  switch param {
-  | list{} => []
-  | list{hd, ...tl} as l =>
-    let a = make(list_length(0, l), hd)
-    let rec fill = (i, param) =>
-      switch param {
-      | list{} => a
-      | list{hd, ...tl} =>
-        unsafe_set(a, i, hd)
-        fill(i + 1, tl)
-      }
-    fill(1, tl)
-  }
+@send external push: (array<'a>, 'a) => unit = "push"
 
-let fold_left = (f, x, a) => {
-  let r = ref(x)
-  for i in 0 to length(a) - 1 {
-    r := f(r.contents, unsafe_get(a, i))
-  }
-  r.contents
-}
+@variadic @send external pushMany: (array<'a>, array<'a>) => unit = "push"
 
-let fold_right = (f, a, x) => {
-  let r = ref(x)
-  for i in length(a) - 1 downto 0 {
-    r := f(unsafe_get(a, i), r.contents)
-  }
-  r.contents
-}
+@send external reverse: array<'a> => unit = "reverse"
+@send external toReversed: array<'a> => array<'a> = "toReversed"
 
-let exists = (p, a) => {
-  let n = length(a)
-  let rec loop = i =>
-    if i == n {
-      false
-    } else if p(unsafe_get(a, i)) {
-      true
-    } else {
-      loop(succ(i))
-    }
-  loop(0)
-}
+@send external shift: array<'a> => option<'a> = "shift"
 
-let for_all = (p, a) => {
-  let n = length(a)
-  let rec loop = i =>
-    if i == n {
-      true
-    } else if p(unsafe_get(a, i)) {
-      loop(succ(i))
-    } else {
-      false
-    }
-  loop(0)
-}
+@variadic @send
+external splice: (array<'a>, ~start: int, ~remove: int, ~insert: array<'a>) => unit = "splice"
+@variadic @send
+external toSpliced: (array<'a>, ~start: int, ~remove: int, ~insert: array<'a>) => array<'a> =
+  "toSpliced"
 
-let mem = (x, a) => {
-  let n = length(a)
-  let rec loop = i =>
-    if i == n {
-      false
-    } else if compare(unsafe_get(a, i), x) == 0 {
-      true
-    } else {
-      loop(succ(i))
-    }
-  loop(0)
-}
+@send external with: (array<'a>, int, 'a) => array<'a> = "with"
 
-let memq = (x, a) => {
-  let n = length(a)
-  let rec loop = i =>
-    if i == n {
-      false
-    } else if x === unsafe_get(a, i) {
-      true
-    } else {
-      loop(succ(i))
-    }
-  loop(0)
-}
+@send external unshift: (array<'a>, 'a) => unit = "unshift"
 
-exception Bottom(int)
-let sort = (cmp, a) => {
-  let maxson = (l, i) => {
-    let i31 = i + i + i + 1
-    let x = ref(i31)
-    if i31 + 2 < l {
-      if cmp(get(a, i31), get(a, i31 + 1)) < 0 {
-        x := i31 + 1
-      }
-      if cmp(get(a, x.contents), get(a, i31 + 2)) < 0 {
-        x := i31 + 2
-      }
-      x.contents
-    } else if i31 + 1 < l && cmp(get(a, i31), get(a, i31 + 1)) < 0 {
-      i31 + 1
-    } else if i31 < l {
-      i31
-    } else {
-      raise(Bottom(i))
-    }
+@variadic @send external unshiftMany: (array<'a>, array<'a>) => unit = "unshift"
+
+@send external concat: (array<'a>, array<'a>) => array<'a> = "concat"
+@variadic @send external concatMany: (array<'a>, array<array<'a>>) => array<'a> = "concat"
+
+@send external flat: array<array<'a>> => array<'a> = "flat"
+
+@send external includes: (array<'a>, 'a) => bool = "includes"
+
+@send external indexOf: (array<'a>, 'a) => int = "indexOf"
+let indexOfOpt = (arr, item) =>
+  switch arr->indexOf(item) {
+  | -1 => None
+  | index => Some(index)
   }
+@send external indexOfFrom: (array<'a>, 'a, int) => int = "indexOf"
 
-  let rec trickledown = (l, i, e) => {
-    let j = maxson(l, i)
-    if cmp(get(a, j), e) > 0 {
-      set(a, i, get(a, j))
-      trickledown(l, j, e)
-    } else {
-      set(a, i, e)
-    }
+@send external join: (array<string>, string) => string = "join"
+
+@deprecated("Use `join` instead") @send
+external joinWith: (array<string>, string) => string = "join"
+
+@send external joinUnsafe: (array<'a>, string) => string = "join"
+
+@deprecated("Use `joinUnsafe` instead") @send
+external joinWithUnsafe: (array<'a>, string) => string = "join"
+
+@send external lastIndexOf: (array<'a>, 'a) => int = "lastIndexOf"
+let lastIndexOfOpt = (arr, item) =>
+  switch arr->lastIndexOf(item) {
+  | -1 => None
+  | index => Some(index)
   }
+@send external lastIndexOfFrom: (array<'a>, 'a, int) => int = "lastIndexOf"
 
-  let trickle = (l, i, e) =>
-    try trickledown(l, i, e) catch {
-    | Bottom(i) => set(a, i, e)
-    }
-  let rec bubbledown = (l, i) => {
-    let j = maxson(l, i)
-    set(a, i, get(a, j))
-    bubbledown(l, j)
+@send external slice: (array<'a>, ~start: int, ~end: int) => array<'a> = "slice"
+@send external sliceToEnd: (array<'a>, ~start: int) => array<'a> = "slice"
+@send external copy: array<'a> => array<'a> = "slice"
+
+@send external sort: (array<'a>, ('a, 'a) => Ordering.t) => unit = "sort"
+@send external toSorted: (array<'a>, ('a, 'a) => Ordering.t) => array<'a> = "toSorted"
+
+@send external toString: array<'a> => string = "toString"
+@send external toLocaleString: array<'a> => string = "toLocaleString"
+
+@send external every: (array<'a>, 'a => bool) => bool = "every"
+@send external everyWithIndex: (array<'a>, ('a, int) => bool) => bool = "every"
+
+@send external filter: (array<'a>, 'a => bool) => array<'a> = "filter"
+@send external filterWithIndex: (array<'a>, ('a, int) => bool) => array<'a> = "filter"
+
+@send external find: (array<'a>, 'a => bool) => option<'a> = "find"
+@send external findWithIndex: (array<'a>, ('a, int) => bool) => option<'a> = "find"
+
+@send external findIndex: (array<'a>, 'a => bool) => int = "findIndex"
+@send external findIndexWithIndex: (array<'a>, ('a, int) => bool) => int = "findIndex"
+
+@send external forEach: (array<'a>, 'a => unit) => unit = "forEach"
+@send external forEachWithIndex: (array<'a>, ('a, int) => unit) => unit = "forEach"
+
+@send external map: (array<'a>, 'a => 'b) => array<'b> = "map"
+@send external mapWithIndex: (array<'a>, ('a, int) => 'b) => array<'b> = "map"
+
+@send external reduce: (array<'b>, ('a, 'b) => 'a, 'a) => 'a = "reduce"
+let reduce = (arr, init, f) => reduce(arr, f, init)
+@send external reduceWithIndex: (array<'b>, ('a, 'b, int) => 'a, 'a) => 'a = "reduce"
+let reduceWithIndex = (arr, init, f) => reduceWithIndex(arr, f, init)
+@send
+external reduceRight: (array<'b>, ('a, 'b) => 'a, 'a) => 'a = "reduceRight"
+let reduceRight = (arr, init, f) => reduceRight(arr, f, init)
+@send
+external reduceRightWithIndex: (array<'b>, ('a, 'b, int) => 'a, 'a) => 'a = "reduceRight"
+let reduceRightWithIndex = (arr, init, f) => reduceRightWithIndex(arr, f, init)
+
+@send external some: (array<'a>, 'a => bool) => bool = "some"
+@send external someWithIndex: (array<'a>, ('a, int) => bool) => bool = "some"
+
+@get_index external get: (array<'a>, int) => option<'a> = ""
+@set_index external set: (array<'a>, int, 'a) => unit = ""
+
+@get_index external getSymbol: (array<'a>, Symbol.t) => option<'b> = ""
+@get_index external getSymbolUnsafe: (array<'a>, Symbol.t) => 'b = ""
+@set_index external setSymbol: (array<'a>, Symbol.t, 'b) => unit = ""
+
+let findIndexOpt = (array: array<'a>, finder: 'a => bool): option<int> =>
+  switch findIndex(array, finder) {
+  | -1 => None
+  | index => Some(index)
   }
 
-  let bubble = (l, i) =>
-    try bubbledown(l, i) catch {
-    | Bottom(i) => i
-    }
-  let rec trickleup = (i, e) => {
-    let father = (i - 1) / 3
-    assert(i != father)
-    if cmp(get(a, father), e) < 0 {
-      set(a, i, get(a, father))
-      if father > 0 {
-        trickleup(father, e)
-      } else {
-        set(a, 0, e)
-      }
-    } else {
-      set(a, i, e)
-    }
+let swapUnsafe = (xs, i, j) => {
+  let tmp = getUnsafe(xs, i)
+  setUnsafe(xs, i, getUnsafe(xs, j))
+  setUnsafe(xs, j, tmp)
+}
+
+module M = {
+  @val external floor: float => float = "Math.floor"
+  @val external random: unit => float = "Math.random"
+  external fromFloat: float => int = "%intoffloat"
+  external toFloat: int => float = "%identity"
+
+  let random_int: (int, int) => int = (min, max) =>
+    floor(random() *. toFloat(max - min))->fromFloat + min
+}
+
+let shuffle = xs => {
+  let len = length(xs)
+  for i in 0 to len - 1 {
+    swapUnsafe(xs, i, M.random_int(i, len)) /* [i,len) */
   }
+}
 
+let toShuffled = xs => {
+  let result = copy(xs)
+  shuffle(result)
+  result
+}
+
+let filterMap = (a, f) => {
   let l = length(a)
-  for i in (l + 1) / 3 - 1 downto 0 {
-    trickle(l, i, get(a, i))
-  }
-  for i in l - 1 downto 2 {
-    let e = get(a, i)
-    set(a, i, get(a, 0))
-    trickleup(bubble(i, 0), e)
-  }
-  if l > 1 {
-    let e = get(a, 1)
-    set(a, 1, get(a, 0))
-    set(a, 0, e)
+  let r = makeUninitializedUnsafe(l)
+  let j = ref(0)
+  for i in 0 to l - 1 {
+    let v = getUnsafe(a, i)
+    switch f(v) {
+    | None => ()
+    | Some(v) =>
+      setUnsafe(r, j.contents, v)
+      j.contents = j.contents + 1
+    }
   }
+  truncateToLengthUnsafe(r, j.contents)
+  r
 }
 
-let cutoff = 5
-let stable_sort = (cmp, a) => {
-  let merge = (src1ofs, src1len, src2, src2ofs, src2len, dst, dstofs) => {
-    let src1r = src1ofs + src1len and src2r = src2ofs + src2len
-    let rec loop = (i1, s1, i2, s2, d) =>
-      if cmp(s1, s2) <= 0 {
-        set(dst, d, s1)
-        let i1 = i1 + 1
-        if i1 < src1r {
-          loop(i1, get(a, i1), i2, s2, d + 1)
-        } else {
-          blit(src2, i2, dst, d + 1, src2r - i2)
-        }
-      } else {
-        set(dst, d, s2)
-        let i2 = i2 + 1
-        if i2 < src2r {
-          loop(i1, s1, i2, get(src2, i2), d + 1)
-        } else {
-          blit(a, i1, dst, d + 1, src1r - i1)
-        }
-      }
-    loop(src1ofs, get(a, src1ofs), src2ofs, get(src2, src2ofs), dstofs)
-  }
+let keepSome = filterMap(_, x => x)
 
-  let isortto = (srcofs, dst, dstofs, len) =>
-    for i in 0 to len - 1 {
-      let e = get(a, srcofs + i)
-      let j = ref(dstofs + i - 1)
-      while j.contents >= dstofs && cmp(get(dst, j.contents), e) > 0 {
-        set(dst, j.contents + 1, get(dst, j.contents))
-        decr(j)
-      }
-      set(dst, j.contents + 1, e)
-    }
+@send external flatMap: (array<'a>, 'a => array<'b>) => array<'b> = "flatMap"
+@send external flatMapWithIndex: (array<'a>, ('a, int) => array<'b>) => array<'b> = "flatMap"
 
-  let rec sortto = (srcofs, dst, dstofs, len) =>
-    if len <= cutoff {
-      isortto(srcofs, dst, dstofs, len)
+let findMap = (arr, f) => {
+  let rec loop = i =>
+    if i == arr->length {
+      None
     } else {
-      let l1 = len / 2
-      let l2 = len - l1
-      sortto(srcofs + l1, dst, dstofs + l1, l2)
-      sortto(srcofs, a, srcofs + l2, l1)
-      merge(srcofs + l2, l1, dst, dstofs + l1, l2, dst, dstofs)
+      switch f(getUnsafe(arr, i)) {
+      | None => loop(i + 1)
+      | Some(_) as r => r
+      }
     }
 
-  let l = length(a)
-  if l <= cutoff {
-    isortto(0, a, 0, l)
-  } else {
-    let l1 = l / 2
-    let l2 = l - l1
-    let t = make(l2, get(a, 0))
-    sortto(l1, t, 0, l2)
-    sortto(0, a, l2, l1)
-    merge(l2, l1, t, 0, l2, a, 0)
-  }
+  loop(0)
 }
 
-let fast_sort = stable_sort
+@send external at: (array<'a>, int) => option<'a> = "at"
+
+let last = a => a->get(a->length - 1)
diff --git a/runtime/Array.resi b/runtime/Array.resi
index 74a7c24724..8b57906b27 100644
--- a/runtime/Array.resi
+++ b/runtime/Array.resi
@@ -1,249 +1,1089 @@
-// FIXME:
-//   This exists for compatibility reason.
-//   Move this into Pervasives or Core
-
-// Caution: `Array.get` is implicitly used by `array[idx]` syntax
-external get: (array<'a>, int) => 'a = "%array_safe_get"
-
-// Caution: `Array.set` is implicitly used by `array[idx]` syntax
-external set: (array<'a>, int, 'a) => unit = "%array_safe_set"
-
-// Below is all deprecated and should be removed in v13
-
-/** Return the length (number of elements) of the given array. */
-@deprecated("Use Core instead. This will be removed in v13")
-external length: array<'a> => int = "%array_length"
-
-/** [Array.make n x] returns a fresh array of length [n],
-   initialized with [x].
-   All the elements of this new array are initially
-   physically equal to [x] (in the sense of the [==] predicate).
-   Consequently, if [x] is mutable, it is shared among all elements
-   of the array, and modifying [x] through one of the array entries
-   will modify all other entries at the same time.
-
-   Raise [Invalid_argument] if [n < 0] or [n > Sys.max_array_length].
-   If the value of [x] is a floating-point number, then the maximum
-   size is only [Sys.max_array_length / 2].*/
-@deprecated("Use Core instead. This will be removed in v13")
-let make: (int, 'a) => array<'a>
-
-/** [Array.create_float n] returns a fresh float array of length [n],
-    with uninitialized data.
-    @since 4.03 */
-@deprecated("Use Core instead. This will be removed in v13")
-let create_float: int => array<float>
-
-/** [Array.init n f] returns a fresh array of length [n],
-   with element number [i] initialized to the result of [f i].
-   In other terms, [Array.init n f] tabulates the results of [f]
-   applied to the integers [0] to [n-1].
-
-   Raise [Invalid_argument] if [n < 0] or [n > Sys.max_array_length].
-   If the return type of [f] is [float], then the maximum
-   size is only [Sys.max_array_length / 2].*/
-@deprecated("Use Core instead. This will be removed in v13")
-let init: (int, int => 'a) => array<'a>
-
-/** [Array.make_matrix dimx dimy e] returns a two-dimensional array
-   (an array of arrays) with first dimension [dimx] and
-   second dimension [dimy]. All the elements of this new matrix
-   are initially physically equal to [e].
-   The element ([x,y]) of a matrix [m] is accessed
-   with the notation [m.(x).(y)].
-
-   Raise [Invalid_argument] if [dimx] or [dimy] is negative or
-   greater than {!Sys.max_array_length}.
-   If the value of [e] is a floating-point number, then the maximum
-   size is only [Sys.max_array_length / 2]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let make_matrix: (int, int, 'a) => array<array<'a>>
-
-/** [Array.append v1 v2] returns a fresh array containing the
-   concatenation of the arrays [v1] and [v2]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let append: (array<'a>, array<'a>) => array<'a>
-
-/** Same as {!Array.append}, but concatenates a list of arrays. */
-@deprecated("Use Core instead. This will be removed in v13")
-let concat: list<array<'a>> => array<'a>
-
-/** [Array.sub a start len] returns a fresh array of length [len],
-   containing the elements number [start] to [start + len - 1]
-   of array [a].
-
-   Raise [Invalid_argument "Array.sub"] if [start] and [len] do not
-   designate a valid subarray of [a]; that is, if
-   [start < 0], or [len < 0], or [start + len > Array.length a]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let sub: (array<'a>, int, int) => array<'a>
-
-/** [Array.copy a] returns a copy of [a], that is, a fresh array
-   containing the same elements as [a]. */
-@deprecated("Use Core instead. This will be removed in v13")
+/**
+ `fromIterator(iterator)`
+
+  Creates an array from the provided `iterator`
+
+  ```res example
+  let map = Map.fromArray([("foo", 1), ("bar", 2)])
+
+  Array.fromIterator(map->Map.values) // [1, 2]
+  ```
+ */
+@val
+external fromIterator: Iterator.t<'a> => array<'a> = "Array.from"
+
+// TODO: Docs
+@val external fromArrayLike: Js.Array2.array_like<'a> => array<'a> = "Array.from"
+
+// TODO: Docs
+@val
+external fromArrayLikeWithMap: (Js.Array2.array_like<'a>, 'a => 'b) => array<'b> = "Array.from"
+
+/**
+  `make(~length, init)`
+
+  Creates an array of length `length` initialized with the value of `init`.
+
+  ```res example
+  Array.make(~length=3, #apple) == [#apple, #apple, #apple]
+  ```
+*/
+let make: (~length: int, 'a) => array<'a>
+
+/**
+  `fromInitializer(~length, f)`
+
+  Creates an array of length `length` initialized with the value returned from `f ` for each index.
+
+  ```res example
+  Array.fromInitializer(~length=3, i => i + 3) == [3, 4, 5]
+  ```
+*/
+let fromInitializer: (~length: int, int => 'a) => array<'a>
+
+let equal: (array<'a>, array<'a>, ('a, 'a) => bool) => bool
+
+let compare: (array<'a>, array<'a>, ('a, 'a) => Ordering.t) => Ordering.t
+
+@val external isArray: 'a => bool = "Array.isArray"
+
+/**
+`length(array)` returns the length of (i.e. number of items in) the array.
+
+See [`Array.length`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/length) on MDN.
+
+## Examples
+```rescript
+let someArray = ["hi", "hello"]
+
+Console.log(someArray->Array.length) // 2
+```
+*/
+@get
+external length: array<'a> => int = "length"
+
+// TODO: Docs
+@send external copyAllWithin: (array<'a>, ~target: int) => array<'a> = "copyWithin"
+
+// TODO: Docs
+@send
+external copyWithinToEnd: (array<'a>, ~target: int, ~start: int) => array<'a> = "copyWithin"
+
+// TODO: Docs
+@send
+external copyWithin: (array<'a>, ~target: int, ~start: int, ~end: int) => array<'a> = "copyWithin"
+
+/**
+`fillAll(array, value)` fills the entire `array` with `value`.
+
+Beware this will *mutate* the array.
+
+See [`Array.fill`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill) on MDN.
+
+## Examples
+```rescript
+let myArray = [1, 2, 3, 4]
+myArray->Array.fillAll(9)
+
+Console.log(myArray) // [9, 9, 9, 9]
+```
+*/
+@send
+external fillAll: (array<'a>, 'a) => unit = "fill"
+
+/**
+`fillToEnd(array, value, ~start)` fills `array` with `value` from the `start` index.
+
+Beware this will *mutate* the array.
+
+See [`Array.fill`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill) on MDN.
+
+## Examples
+```rescript
+let myArray = [1, 2, 3, 4]
+myArray->Array.fillToEnd(9, ~start=1)
+
+Console.log(myArray) // [1, 9, 9, 9]
+```
+*/
+@send
+external fillToEnd: (array<'a>, 'a, ~start: int) => unit = "fill"
+
+/**
+`fill(array, value, ~start, ~end)` fills `array` with `value` from `start` to `end`.
+
+Beware this will *mutate* the array.
+
+See [`Array.fill`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill) on MDN.
+
+## Examples
+```rescript
+let myArray = [1, 2, 3, 4]
+myArray->Array.fill(9, ~start=1, ~end=2)
+
+Console.log(myArray) // [1, 9, 9, 4]
+```
+*/
+@send
+external fill: (array<'a>, 'a, ~start: int, ~end: int) => unit = "fill"
+
+/**
+`pop(array)` removes the last item from `array` and returns it.
+
+Beware this will *mutate* the array.
+
+See [`Array.pop`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/pop) on MDN.
+
+## Examples
+```rescript
+let someArray = ["hi", "hello"]
+let lastItem = someArray->Array.pop // "hello"
+
+Console.log(someArray) // ["hi"]. Notice last item is gone.
+```
+*/
+@send
+external pop: array<'a> => option<'a> = "pop"
+
+/**
+`push(array, item)` appends `item` to the end of `array`.
+
+Beware this will *mutate* the array.
+
+See [`Array.push`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/push) on MDN.
+
+## Examples
+```rescript
+let someArray = ["hi", "hello"]
+someArray->Array.push("yay")
+
+Console.log(someArray) // ["hi", "hello", "yay"]
+```
+*/
+@send
+external push: (array<'a>, 'a) => unit = "push"
+
+/**
+`pushMany(array, itemsArray)` appends many new items to the end of the array.
+
+Beware this will *mutate* the array.
+
+See [`Array.push`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/push) on MDN.
+
+## Examples
+```rescript
+let someArray = ["hi", "hello"]
+someArray->Array.pushMany(["yay", "wehoo"])
+
+Console.log(someArray) // ["hi", "hello", "yay", "wehoo"]
+```
+*/
+@variadic
+@send
+external pushMany: (array<'a>, array<'a>) => unit = "push"
+
+/**
+`reverse(array)` reverses the order of the items in `array`.
+
+Beware this will *mutate* the array.
+
+See [`Array.reverse`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reverse) on MDN.
+
+## Examples
+```rescript
+let someArray = ["hi", "hello"]
+someArray->Array.reverse
+
+Console.log(someArray) // ["hello", "h1"]
+```
+*/
+@send
+external reverse: array<'a> => unit = "reverse"
+
+/**
+`shift(array)` removes the first item in the array, and returns it.
+
+Beware this will *mutate* the array.
+
+See [`Array.shift`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/shift) on MDN.
+
+## Examples
+```rescript
+let someArray = ["hi", "hello"]
+let lastItem = someArray->Array.shift // "hi"
+
+Console.log(someArray) // ["hello"]. Notice first item is gone.
+```
+*/
+@send
+external shift: array<'a> => option<'a> = "shift"
+
+/**
+`toSorted(array, comparator)` returns a new, sorted array from `array`, using the `comparator` function.
+
+See [`Array.toSorted`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toSorted) on MDN.
+
+## Examples
+```rescript
+let someArray = [3, 2, 1]
+let sorted = someArray->Array.toSorted(Int.compare)
+
+Console.log(sorted) // [1, 2, 3]
+Console.log(someArray) // [3, 2, 1]. Original unchanged
+```
+*/
+@send
+external toSorted: (array<'a>, ('a, 'a) => Ordering.t) => array<'a> = "toSorted"
+
+/**
+`sort(array, comparator)` sorts `array` in-place using the `comparator` function.
+
+Beware this will *mutate* the array.
+
+See [`Array.sort`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort) on MDN.
+
+## Examples
+```rescript
+let someArray = [3, 2, 1]
+someArray->Array.sort((a, b) => float(a - b))
+
+Console.log(someArray) // [1, 2, 3]
+```
+*/
+@send
+external sort: (array<'a>, ('a, 'a) => Ordering.t) => unit = "sort"
+
+@variadic @send
+external splice: (array<'a>, ~start: int, ~remove: int, ~insert: array<'a>) => unit = "splice"
+
+@variadic @send
+external toSpliced: (array<'a>, ~start: int, ~remove: int, ~insert: array<'a>) => array<'a> =
+  "toSpliced"
+
+@send external with: (array<'a>, int, 'a) => array<'a> = "with"
+
+/**
+`unshift(array, item)` inserts a new item at the start of the array.
+
+Beware this will *mutate* the array.
+
+See [`Array.unshift`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/unshift) on MDN.
+
+## Examples
+```rescript
+let someArray = ["hi", "hello"]
+someArray->Array.unshift("yay")
+
+Console.log(someArray) // ["yay", "hi", "hello"]
+```
+*/
+@send
+external unshift: (array<'a>, 'a) => unit = "unshift"
+
+/**
+`unshiftMany(array, itemsArray)` inserts many new items to the start of the array.
+
+Beware this will *mutate* the array.
+
+See [`Array.push`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/unshift) on MDN.
+
+## Examples
+```rescript
+let someArray = ["hi", "hello"]
+someArray->Array.unshiftMany(["yay", "wehoo"])
+
+Console.log(someArray) // ["yay", "wehoo", "hi", "hello"]
+```
+*/
+@variadic
+@send
+external unshiftMany: (array<'a>, array<'a>) => unit = "unshift"
+
+/**
+`concat(array1, array2)` concatenates the two arrays, creating a new array.
+
+See [`Array.concat`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/concat) on MDN.
+
+## Examples
+```rescript
+let array1 = ["hi", "hello"]
+let array2 = ["yay", "wehoo"]
+
+let someArray = array1->Array.concat(array2)
+
+Console.log(someArray) // ["hi", "hello", "yay", "wehoo"]
+```
+*/
+@send
+external concat: (array<'a>, array<'a>) => array<'a> = "concat"
+
+/**
+`concatMany(array1, arrays)` concatenates array1 with several other arrays, creating a new array.
+
+See [`Array.concat`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/concat) on MDN.
+
+## Examples
+```rescript
+let array1 = ["hi", "hello"]
+let array2 = ["yay"]
+let array3 = ["wehoo"]
+
+let someArray = array1->Array.concatMany([array2, array3])
+
+Console.log(someArray) // ["hi", "hello", "yay", "wehoo"]
+```
+*/
+@variadic
+@send
+external concatMany: (array<'a>, array<array<'a>>) => array<'a> = "concat"
+
+/**
+`flat(arrays)` concatenates an array of arrays into a single array.
+
+See [`Array.flat`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat) on MDN.
+
+## Examples
+```rescript
+Console.log([[1], [2], [3, 4]]->Array.flat) // [1, 2, 3, 4]
+```
+*/
+@send
+external flat: array<array<'a>> => array<'a> = "flat"
+
+/**
+`includes(array, item)` checks whether `array` includes `item`, by doing a [strict check for equality](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Strict_equality).
+
+See [`Array.includes`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes) on MDN.
+
+## Examples
+```rescript
+Console.log([1, 2]->Array.includes(1)) // true
+Console.log([1, 2]->Array.includes(3)) // false
+Console.log([{"language": "ReScript"}]->Array.includes({"language": "ReScript"})) // false, because of strict equality
+```
+*/
+@send
+external includes: (array<'a>, 'a) => bool = "includes"
+
+/**
+`indexOf(array, item)` returns the index of the provided `item` in `array`. Uses [strict check for equality](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Strict_equality) when comparing items.
+
+Returns `-1` if the item doesn not exist. Check out `Array.indexOfOpt` for a version that returns `None` instead of `-1` if the item does not exist.
+
+See [`Array.indexOf`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf) on MDN.
+
+## Examples
+```rescript
+Console.log([1, 2]->Array.indexOf(2)) // 1
+Console.log([1, 2]->Array.indexOf(3)) // -1
+Console.log([{"language": "ReScript"}]->Array.indexOf({"language": "ReScript"})) // -1, because of strict equality
+```
+*/
+@send
+external indexOf: (array<'a>, 'a) => int = "indexOf"
+
+/**
+`indexOfOpt(array, item)` returns an option of the index of the provided `item` in `array`. Uses [strict check for equality](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Strict_equality) when comparing items.
+
+See [`Array.indexOf`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf) on MDN.
+
+## Examples
+```rescript
+Console.log([1, 2]->Array.indexOfOpt(2)) // Some(1)
+Console.log([1, 2]->Array.indexOfOpt(3)) // None
+Console.log([{"language": "ReScript"}]->Array.indexOfOpt({"language": "ReScript"})) // None, because of strict equality
+```
+*/
+let indexOfOpt: (array<'a>, 'a) => option<int>
+@send external indexOfFrom: (array<'a>, 'a, int) => int = "indexOf"
+
+/**
+`join(array, separator)` produces a string where all items of `array` are printed, separated by `separator`. Array items must be strings, to join number or other arrays, use `joinUnsafe`. Under the hood this will run JavaScript's `toString` on all the array items.
+
+See [Array.join](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/join)
+
+## Examples
+```rescript
+let array = ["One", "Two", "Three"]
+
+Console.log(array->Array.join(" -- ")) // One -- Two -- Three
+```
+*/
+@send
+external join: (array<string>, string) => string = "join"
+
+/**
+`joinWith(array, separator)` produces a string where all items of `array` are printed, separated by `separator`. Array items must be strings, to join number or other arrays, use `joinWithUnsafe`. Under the hood this will run JavaScript's `toString` on all the array items.
+
+## Examples
+```rescript
+let array = ["One", "Two", "Three"]
+
+Console.log(array->Array.joinWith(" -- ")) // One -- Two -- Three
+```
+*/
+@deprecated("Use `join` instead")
+@send
+external joinWith: (array<string>, string) => string = "join"
+
+/**
+`joinUnsafe(array, separator)` produces a string where all items of `array` are printed, separated by `separator`. Under the hood this will run JavaScript's `toString` on all the array items.
+
+See [Array.join](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/join)
+
+## Examples
+```rescript
+let array = [1, 2, 3]
+
+Console.log(array->Array.joinUnsafe(" -- ")) // 1 -- 2 -- 3
+```
+*/
+@send
+external joinUnsafe: (array<'a>, string) => string = "join"
+
+/**
+`joinWithUnsafe(array, separator)` produces a string where all items of `array` are printed, separated by `separator`. Under the hood this will run JavaScript's `toString` on all the array items.
+
+## Examples
+```rescript
+let array = [1, 2, 3]
+
+Console.log(array->Array.joinWithUnsafe(" -- ")) // 1 -- 2 -- 3
+```
+*/
+@deprecated("Use `joinUnsafe` instead")
+@send
+external joinWithUnsafe: (array<'a>, string) => string = "join"
+@send external lastIndexOf: (array<'a>, 'a) => int = "lastIndexOf"
+let lastIndexOfOpt: (array<'a>, 'a) => option<int>
+@send external lastIndexOfFrom: (array<'a>, 'a, int) => int = "lastIndexOf"
+
+/**
+`slice(array, ~start, ~end)` creates a new array of items copied from `array` from `start` until (but not including) `end`.
+
+See [`Array.slice`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/slice) on MDN.
+
+## Examples
+```rescript
+let myArray = [1, 2, 3, 4]
+
+Console.log(myArray->Array.slice(~start=1, ~end=3)) // [2, 3]
+```
+*/
+@send
+external slice: (array<'a>, ~start: int, ~end: int) => array<'a> = "slice"
+
+/**
+`sliceToEnd(array, start)` creates a new array from `array`, with all items from `array` starting from `start`.
+
+See [`Array.slice`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/slice) on MDN.
+
+## Examples
+```rescript
+let myArray = [1, 2, 3, 4]
+
+Console.log(myArray->Array.sliceToEnd(~start=1)) // [2, 3, 4]
+```
+*/
+@send
+external sliceToEnd: (array<'a>, ~start: int) => array<'a> = "slice"
+/**
+`copy(array)` makes a copy of the array with the items in it, but does not make copies of the items themselves.
+
+## Examples
+```rescript
+let myArray = [1, 2, 3]
+let copyOfMyArray = myArray->Array.copy
+
+Console.log(copyOfMyArray) // [1, 2, 3]
+Console.log(myArray === copyOfMyArray) // false
+```
+*/
 @send
 external copy: array<'a> => array<'a> = "slice"
 
-/** [Array.fill a ofs len x] modifies the array [a] in place,
-   storing [x] in elements number [ofs] to [ofs + len - 1].
-
-   Raise [Invalid_argument "Array.fill"] if [ofs] and [len] do not
-   designate a valid subarray of [a]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let fill: (array<'a>, int, int, 'a) => unit
-
-/** [Array.blit v1 o1 v2 o2 len] copies [len] elements
-   from array [v1], starting at element number [o1], to array [v2],
-   starting at element number [o2]. It works correctly even if
-   [v1] and [v2] are the same array, and the source and
-   destination chunks overlap.
-
-   Raise [Invalid_argument "Array.blit"] if [o1] and [len] do not
-   designate a valid subarray of [v1], or if [o2] and [len] do not
-   designate a valid subarray of [v2]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let blit: (array<'a>, int, array<'a>, int, int) => unit
-
-/** [Array.to_list a] returns the list of all the elements of [a]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let to_list: array<'a> => list<'a>
-
-/** [Array.of_list l] returns a fresh array containing the elements
-   of [l]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let of_list: list<'a> => array<'a>
-
-/* {1 Iterators} */
-
-/** [Array.iter f a] applies function [f] in turn to all
-   the elements of [a].  It is equivalent to
-   [f a.(0); f a.(1); ...; f a.(Array.length a - 1); ()]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let iter: ('a => unit, array<'a>) => unit
-
-/** Same as {!Array.iter}, but the
-   function is applied with the index of the element as first argument,
-   and the element itself as second argument. */
-@deprecated("Use Core instead. This will be removed in v13")
-let iteri: ((int, 'a) => unit, array<'a>) => unit
-
-/** [Array.map f a] applies function [f] to all the elements of [a],
-   and builds an array with the results returned by [f]:
-   [[| f a.(0); f a.(1); ...; f a.(Array.length a - 1) |]]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let map: ('a => 'b, array<'a>) => array<'b>
-
-/** Same as {!Array.map}, but the
-   function is applied to the index of the element as first argument,
-   and the element itself as second argument. */
-@deprecated("Use Core instead. This will be removed in v13")
-let mapi: ((int, 'a) => 'b, array<'a>) => array<'b>
-
-/** [Array.fold_left f x a] computes
-   [f (... (f (f x a.(0)) a.(1)) ...) a.(n-1)],
-   where [n] is the length of the array [a]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let fold_left: (('a, 'b) => 'a, 'a, array<'b>) => 'a
-
-/** [Array.fold_right f a x] computes
-   [f a.(0) (f a.(1) ( ... (f a.(n-1) x) ...))],
-   where [n] is the length of the array [a]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let fold_right: (('b, 'a) => 'a, array<'b>, 'a) => 'a
-
-/* {1 Iterators on two arrays} */
-
-/** [Array.iter2 f a b] applies function [f] to all the elements of [a]
-   and [b].
-   Raise [Invalid_argument] if the arrays are not the same size.
-   @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let iter2: (('a, 'b) => unit, array<'a>, array<'b>) => unit
-
-/** [Array.map2 f a b] applies function [f] to all the elements of [a]
-   and [b], and builds an array with the results returned by [f]:
-   [[| f a.(0) b.(0); ...; f a.(Array.length a - 1) b.(Array.length b - 1)|]].
-   Raise [Invalid_argument] if the arrays are not the same size.
-   @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let map2: (('a, 'b) => 'c, array<'a>, array<'b>) => array<'c>
-
-/* {1 Array scanning} */
-
-/** [Array.for_all p [|a1; ...; an|]] checks if all elements of the array
-   satisfy the predicate [p]. That is, it returns
-   [(p a1) && (p a2) && ... && (p an)].
-   @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let for_all: ('a => bool, array<'a>) => bool
-
-/** [Array.exists p [|a1; ...; an|]] checks if at least one element of
-    the array satisfies the predicate [p]. That is, it returns
-    [(p a1) || (p a2) || ... || (p an)].
-    @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let exists: ('a => bool, array<'a>) => bool
-
-/** [mem a l] is true if and only if [a] is equal
-   to an element of [l].
-   @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let mem: ('a, array<'a>) => bool
-
-/** Same as {!Array.mem}, but uses physical equality instead of structural
-   equality to compare array elements.
-   @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let memq: ('a, array<'a>) => bool
-
-/* {1 Sorting} */
-
-/** Sort an array in increasing order according to a comparison
-   function.  The comparison function must return 0 if its arguments
-   compare as equal, a positive integer if the first is greater,
-   and a negative integer if the first is smaller (see below for a
-   complete specification).  For example, {!Pervasives.compare} is
-   a suitable comparison function, provided there are no floating-point
-   NaN values in the data.  After calling [Array.sort], the
-   array is sorted in place in increasing order.
-   [Array.sort] is guaranteed to run in constant heap space
-   and (at most) logarithmic stack space.
-
-   The current implementation uses Heap Sort.  It runs in constant
-   stack space.
-
-   Specification of the comparison function:
-   Let [a] be the array and [cmp] the comparison function.  The following
-   must be true for all x, y, z in a :
--   [cmp x y] > 0 if and only if [cmp y x] < 0
--   if [cmp x y] >= 0 and [cmp y z] >= 0 then [cmp x z] >= 0
-
-   When [Array.sort] returns, [a] contains the same elements as before,
-   reordered in such a way that for all i and j valid indices of [a] :
--   [cmp a.(i) a.(j)] >= 0 if and only if i >= j
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let sort: (('a, 'a) => int, array<'a>) => unit
-
-/** Same as {!Array.sort}, but the sorting algorithm is stable (i.e.
-   elements that compare equal are kept in their original order) and
-   not guaranteed to run in constant heap space.
-
-   The current implementation uses Merge Sort. It uses [n/2]
-   words of heap space, where [n] is the length of the array.
-   It is usually faster than the current implementation of {!Array.sort}.
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let stable_sort: (('a, 'a) => int, array<'a>) => unit
-
-/** Same as {!Array.sort} or {!Array.stable_sort}, whichever is faster
-    on typical input.
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let fast_sort: (('a, 'a) => int, array<'a>) => unit
-
-@deprecated("Use Core instead. This will be removed in v13")
+/**
+`toString(array)` stringifies `array` by running `toString` on all of the array elements and joining them with ",".
+
+See [`Array.toString`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toString) on MDN.
+
+## Examples
+```rescript
+let array = [1, 2, 3, 4]
+
+Console.log(array->Array.toString) // "1,2,3,4"
+```
+*/
+@send
+external toString: array<'a> => string = "toString"
+
+@send external toLocaleString: array<'a> => string = "toLocaleString"
+
+/**
+`every(array, predicate)` returns true if `predicate` returns true for all items in `array`.
+
+See [`Array.every`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every) on MDN.
+
+## Examples
+```rescript
+let array = [1, 2, 3, 4]
+
+Console.log(array->Array.every(num => num <= 4)) // true
+Console.log(array->Array.every(num => num === 1)) // false
+```
+*/
+@send
+external every: (array<'a>, 'a => bool) => bool = "every"
+
+/**
+`everyWithIndex(array, checker)` returns true if all items in `array` returns true when running the provided `checker` function.
+
+See [`Array.every`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every) on MDN.
+
+## Examples
+```rescript
+let array = [1, 2, 3, 4]
+
+Console.log(array->Array.everyWithIndex((num, index) => index < 2 && num <= 2)) // true
+Console.log(array->Array.everyWithIndex((num, index) => index < 2 && num >= 2)) // false
+```
+*/
+@send
+external everyWithIndex: (array<'a>, ('a, int) => bool) => bool = "every"
+
+/**
+`filter(array, checker)` returns a new array containing all elements from `array` for which the provided `checker` function returns true.
+
+See [`Array.filter`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter) on MDN.
+
+## Examples
+```rescript
+let array = [1, 2, 3, 4]
+
+Console.log(array->Array.filter(num => num > 2)) // [3, 4]
+```
+*/
+@send
+external filter: (array<'a>, 'a => bool) => array<'a> = "filter"
+
+/**
+`filterWithIndex(array, checker)` returns a new array containing all elements from `array` for which the provided `checker` function returns true.
+
+See [`Array.filter`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter) on MDN.
+
+## Examples
+```rescript
+let array = [1, 2, 3, 4]
+
+Console.log(array->Array.filterWithIndex((num, index) => index === 0 || num === 2)) // [1, 2]
+```
+*/
+@send
+external filterWithIndex: (array<'a>, ('a, int) => bool) => array<'a> = "filter"
+
+/**
+`find(array, checker)` returns the first element of `array` where the provided `checker` function returns true.
+
+See [`Array.find`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find) on MDN.
+
+## Examples
+```rescript
+type languages = ReScript | TypeScript | JavaScript
+
+let array = [ReScript, TypeScript, JavaScript]
+
+switch array->Array.find(item => item == ReScript) {
+| None => Console.log("No item...")
+| Some(_) => Console.log("Yay, ReScript!")
+}
+```
+*/
+@send
+external find: (array<'a>, 'a => bool) => option<'a> = "find"
+
+/**
+`findWithIndex(array, checker)` returns the first element of `array` where the provided `checker` function returns true.
+
+See [`Array.find`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find) on MDN.
+
+## Examples
+```rescript
+type languages = ReScript | TypeScript | JavaScript
+
+let array = [TypeScript, JavaScript, ReScript]
+
+switch array->Array.findWithIndex((item, index) => index > 1 && item == ReScript) {
+| None => Console.log("No item...")
+| Some(_) => Console.log("Yay, ReScript exists in a later position!")
+}
+```
+*/
+@send
+external findWithIndex: (array<'a>, ('a, int) => bool) => option<'a> = "find"
+
+/**
+`findIndex(array, checker)` returns the index of the first element of `array` where the provided `checker` function returns true.
+
+Returns `-1` if the item does not exist. Consider using `Array.findIndexOpt` if you want an option instead (where `-1` would be `None`).
+
+See [`Array.findIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex) on MDN.
+
+## Examples
+```rescript
+type languages = ReScript | TypeScript | JavaScript
+
+let array = [ReScript, JavaScript]
+
+Console.log(array->Array.findIndex(item => item == ReScript)) // 0
+Console.log(array->Array.findIndex(item => item == TypeScript)) // -1
+```
+*/
+@send
+external findIndex: (array<'a>, 'a => bool) => int = "findIndex"
+
+/**
+`findIndexWithIndex(array, checker)` returns the index of the first element of `array` where the provided `checker` function returns true.
+
+Returns `-1` if the item does not exist. Consider using `Array.findIndexOpt` if you want an option instead (where `-1` would be `None`).
+
+See [`Array.findIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex) on MDN.
+
+## Examples
+```rescript
+type languages = ReScript | TypeScript | JavaScript
+
+let array = [ReScript, JavaScript]
+
+let isReScriptFirst = array->Array.findIndexWithIndex((item, index) => index === 0 && item == ReScript)
+let isTypeScriptFirst = array->Array.findIndexWithIndex((item, index) => index === 0 && item == TypeScript)
+
+Console.log(isReScriptFirst) // 0
+Console.log(isTypeScriptFirst) // -1
+```
+*/
+@send
+external findIndexWithIndex: (array<'a>, ('a, int) => bool) => int = "findIndex"
+
+/**
+`forEach(array, fn)` runs the provided `fn` on every element of `array`.
+
+See [`Array.forEach`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach) on MDN.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+
+array->Array.forEach(item => {
+  Console.log(item)
+})
+```
+*/
+@send
+external forEach: (array<'a>, 'a => unit) => unit = "forEach"
+
+/**
+`forEachWithIndex(array, fn)` runs the provided `fn` on every element of `array`.
+
+See [`Array.forEach`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach) on MDN.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+
+array->Array.forEachWithIndex((item, index) => {
+  Console.log("At item " ++ Int.toString(index) ++ ": " ++ item)
+})
+```
+*/
+@send
+external forEachWithIndex: (array<'a>, ('a, int) => unit) => unit = "forEach"
+
+/**
+`map(array, fn)` returns a new array with all elements from `array`, each element transformed using the provided `fn`.
+
+See [`Array.map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map) on MDN.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+let mappedArray = array->Array.map(greeting => greeting ++ " to you")
+
+Console.log(mappedArray) // ["Hello to you", "Hi to you", "Good bye to you"]
+```
+*/
+@send
+external map: (array<'a>, 'a => 'b) => array<'b> = "map"
+
+/**
+`mapWithIndex(array, fn)` returns a new array with all elements from `array`, each element transformed using the provided `fn`.
+
+See [`Array.map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map) on MDN.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+let mappedArray =
+  array->Array.mapWithIndex((greeting, index) =>
+    greeting ++ " at position " ++ Int.toString(index)
+  )
+
+Console.log(mappedArray) // ["Hello at position 0", "Hi at position 1", "Good bye at position 2"]
+```
+*/
+@send
+external mapWithIndex: (array<'a>, ('a, int) => 'b) => array<'b> = "map"
+
+/**
+  `reduce(xs, init, fn)`
+
+  Applies `fn` to each element of `xs` from beginning to end. Function `fn` has two parameters: the item from the list and an “accumulator”; which starts with a value of `init`. `reduce` returns the final value of the accumulator.
+
+  ```res example
+  Array.reduce([2, 3, 4], 1, (a, b) => a + b) == 10
+
+  Array.reduce(["a", "b", "c", "d"], "", (a, b) => a ++ b) == "abcd"
+  ```
+*/
+let reduce: (array<'a>, 'b, ('b, 'a) => 'b) => 'b
+
+/**
+  `reduceWithIndex(x, init, fn)`
+
+  Applies `fn` to each element of `xs` from beginning to end. Function `fn` has three parameters: the item from the array and an “accumulator”, which starts with a value of `init` and the index of each element. `reduceWithIndex` returns the final value of the accumulator.
+
+  ```res example
+  Array.reduceWithIndex([1, 2, 3, 4], 0, (acc, x, i) => acc + x + i) == 16
+  ```
+*/
+let reduceWithIndex: (array<'a>, 'b, ('b, 'a, int) => 'b) => 'b
+
+/**
+  `reduceRight(xs, init, fn)`
+
+  Works like `Array.reduce`; except that function `fn` is applied to each item of `xs` from the last back to the first.
+
+  ```res example
+  Array.reduceRight(["a", "b", "c", "d"], "", (a, b) => a ++ b) == "dcba"
+  ```
+*/
+let reduceRight: (array<'a>, 'b, ('b, 'a) => 'b) => 'b
+
+/**
+  `reduceRightWithIndex(xs, init, fn)`
+
+  Like `reduceRight`, but with an additional index argument on the callback function.
+
+  ```res example
+  Array.reduceRightWithIndex([1, 2, 3, 4], 0, (acc, x, i) => acc + x + i) == 16
+  ```
+*/
+let reduceRightWithIndex: (array<'a>, 'b, ('b, 'a, int) => 'b) => 'b
+
+/**
+`some(array, predicate)` returns true if `predicate` returns true for any element in `array`.
+
+See [`Array.some`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some) on MDN.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+
+Console.log(array->Array.some(greeting => greeting === "Hello")) // true
+```
+*/
+@send
+external some: (array<'a>, 'a => bool) => bool = "some"
+
+/**
+`someWithIndex(array, checker)` returns true if running the provided `checker` function on any element in `array` returns true.
+
+See [`Array.some`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some) on MDN.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+
+Console.log(array->Array.someWithIndex((greeting, index) => greeting === "Hello" && index === 0)) // true
+```
+*/
+@send
+external someWithIndex: (array<'a>, ('a, int) => bool) => bool = "some"
+
+/**
+`get(array, index)` returns the element at `index` of `array`.
+
+Returns `None` if the index does not exist in the array. Equivalent to doing `array[index]` in JavaScript.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+
+array->Array.get(0) == Some("Hello") // true
+array->Array.get(3) == None // true
+```
+*/
+@get_index
+external get: (array<'a>, int) => option<'a> = ""
+
+/**
+`set(array, index, item)` sets the provided `item` at `index` of `array`.
+
+Beware this will *mutate* the array.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+array->Array.set(1, "Hello")
+
+Console.log(array[1]) // "Hello"
+```
+*/
+@set_index
+external set: (array<'a>, int, 'a) => unit = ""
+@get_index external getSymbol: (array<'a>, Symbol.t) => option<'b> = ""
+@get_index external getSymbolUnsafe: (array<'a>, Symbol.t) => 'b = ""
+@set_index external setSymbol: (array<'a>, Symbol.t, 'b) => unit = ""
+
+/**
+`getUnsafe(array, index)` returns the element at `index` of `array`.
+
+This is _unsafe_, meaning it will return `undefined` value if `index` does not exist in `array`.
+
+Use `Array.getUnsafe` only when you are sure the `index` exists (i.e. when using for-loop).
+
+## Examples
+```rescript
+let array = [1, 2, 3]
+for index in 0 to array->Array.length - 1 {
+  let value = array->Array.getUnsafe(index)
+  Console.log(value)
+}
+```
+*/
+external getUnsafe: (array<'a>, int) => 'a = "%array_unsafe_get"
+
+/**
+`unsafe_get(array, index)` returns the element at `index` of `array`.
+
+This is _unsafe_, meaning it will return `undefined` value if `index` does not exist in `array`.
+
+Use `Array.unsafe_get` only when you are sure the `index` exists (i.e. when using for-loop).
+
+## Examples
+```rescript
+let array = [1, 2, 3]
+for index in 0 to array->Array.length - 1 {
+  let value = array->Array.unsafe_get(index)
+  Console.log(value)
+}
+```
+*/
+@deprecated("Use getUnsafe instead. This will be removed in v13")
 external unsafe_get: (array<'a>, int) => 'a = "%array_unsafe_get"
 
-@deprecated("Use Core instead. This will be removed in v13")
-external unsafe_set: (array<'a>, int, 'a) => unit = "%array_unsafe_set"
+/**
+`setUnsafe(array, index, item)` sets the provided `item` at `index` of `array`.
+
+Beware this will *mutate* the array, and is *unsafe*.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+array->Array.setUnsafe(1, "Hello")
+
+Console.log(array[1]) // "Hello"
+```
+*/
+external setUnsafe: (array<'a>, int, 'a) => unit = "%array_unsafe_set"
+
+/**
+`findIndexOpt(array, checker)` returns the index of the first element of `array` where the provided `checker` function returns true.
+
+Returns `None` if no item matches.
+
+See [`Array.findIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex) on MDN.
+
+## Examples
+```rescript
+type languages = ReScript | TypeScript | JavaScript
+
+let array = [ReScript, TypeScript, JavaScript]
+
+switch array->Array.findIndexOpt(item => item == ReScript) {
+| None => Console.log("Ahh, no ReScript...")
+| Some(index) => Console.log("Yay, ReScript at index " ++ Int.toString(index))
+}
+```
+*/
+let findIndexOpt: (array<'a>, 'a => bool) => option<int>
+
+/**
+`toReversed(array)` creates a new array with all items from `array` in reversed order.
+
+See [`Array.toReversed`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toReversed) on MDN.
+
+## Examples
+```rescript
+let someArray = ["hi", "hello"]
+let reversed = someArray->Array.toReversed
+
+Console.log(reversed) // ["hello", "h1"]
+Console.log(someArray) // ["h1", "hello"]. Original unchanged
+```
+*/
+@send
+external toReversed: array<'a> => array<'a> = "toReversed"
+
+/**
+`filterMap(array, fn)`
+
+Calls `fn` for each element and returns a new array containing results of the `fn` calls which are not `None`.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+
+Console.log(
+  array->Array.filterMap(item =>
+    switch item {
+    | "Hello" => Some(item->String.length)
+    | _ => None
+    }
+  ),
+) // [5]
+```
+*/
+let filterMap: (array<'a>, 'a => option<'b>) => array<'b>
+
+/**
+  `keepSome(arr)`
+
+  Returns a new array containing `value` for all elements that are `Some(value)`
+  and ignoring every value that is `None`
+
+  ```res example
+  Array.keepSome([Some(1), None, Some(3)]) == [1, 3]
+  ```
+*/
+let keepSome: array<option<'a>> => array<'a>
+
+/**
+`toShuffled(array)` returns a new array with all items in `array` in a random order.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+let shuffledArray = array->Array.toShuffled
+
+Console.log(shuffledArray)
+```
+*/
+let toShuffled: array<'a> => array<'a>
+
+/**
+`shuffle(array)` randomizes the position of all items in `array`.
+
+Beware this will *mutate* the array.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+array->Array.shuffle
+
+Console.log(array)
+```
+*/
+let shuffle: array<'a> => unit
+
+/**
+`flatMap(array, mapper)` returns a new array concatenating the arrays returned from running `mapper` on all items in `array`.
+
+## Examples
+```rescript
+type language = ReScript | TypeScript | JavaScript
+
+let array = [ReScript, TypeScript, JavaScript]
+
+Console.log(
+  array->Array.flatMap(item =>
+    switch item {
+    | ReScript => [1, 2, 3]
+    | TypeScript => [4, 5, 6]
+    | JavaScript => [7, 8, 9]
+    }
+  ),
+)
+// [1, 2, 3, 4, 5, 6, 7, 8, 9]
+```
+*/
+@send
+external flatMap: (array<'a>, 'a => array<'b>) => array<'b> = "flatMap"
+
+/**
+`flatMapWithIndex(array, mapper)` returns a new array concatenating the arrays returned from running `mapper` on all items in `array`.
+
+## Examples
+```rescript
+type language = ReScript | TypeScript | JavaScript
+
+let array = [ReScript, TypeScript, JavaScript]
+
+Console.log(
+  array->Array.flatMapWithIndex((item, index) =>
+    switch item {
+    | ReScript => [index]
+    | TypeScript => [index, index + 1]
+    | JavaScript => [index, index + 1, index + 2]
+    }
+  ),
+)
+// [0, 1, 2, 2, 3, 4]
+```
+*/
+@send
+external flatMapWithIndex: (array<'a>, ('a, int) => array<'b>) => array<'b> = "flatMap"
+
+/**
+  `findMap(arr, fn)`
+
+  Calls `fn` for each element and returns the first value from `fn` that is `Some(_)`.
+  Otherwise returns `None`
+
+  ```res example
+  Array.findMap([1, 2, 3], n => mod(n, 2) == 0 ? Some(n - 2) : None) == Some(0) // true
+  ```
+*/
+let findMap: (array<'a>, 'a => option<'b>) => option<'b>
+
+/**
+  `at(array, index)`
+
+  Get an element by its index. Negative indices count backwards from the last item.
+
+  ## Examples
+  ```rescript
+  ["a", "b", "c"]->Array.at(0) // Some("a")
+  ["a", "b", "c"]->Array.at(2) // Some("c")
+  ["a", "b", "c"]->Array.at(3) // None
+  ["a", "b", "c"]->Array.at(-1) // Some("c")
+  ["a", "b", "c"]->Array.at(-3) // Some("a")
+  ["a", "b", "c"]->Array.at(-4) // None
+  ```
+*/
+@send
+external at: (array<'a>, int) => option<'a> = "at"
+
+/**
+`last(array)` returns the last element of `array`.
+
+Returns `None` if the array is empty.
+
+## Examples
+```rescript
+let array = ["Hello", "Hi", "Good bye"]
+
+array->Array.last == Some("Good bye") // true
+[]->Array.last == None // true
+```
+*/
+let last: array<'a> => option<'a>
diff --git a/runtime/ArrayBuffer.res b/runtime/ArrayBuffer.res
new file mode 100644
index 0000000000..0beb684b40
--- /dev/null
+++ b/runtime/ArrayBuffer.res
@@ -0,0 +1,7 @@
+type t = Js.TypedArray2.ArrayBuffer.t
+
+@new external make: int => t = "ArrayBuffer"
+@get external byteLength: t => int = "byteLength"
+
+@send external slice: (t, ~start: int, ~end: int) => t = "slice"
+@send external sliceToEnd: (t, ~start: int) => t = "slice"
diff --git a/runtime/AsyncIterator.res b/runtime/AsyncIterator.res
new file mode 100644
index 0000000000..56abad2837
--- /dev/null
+++ b/runtime/AsyncIterator.res
@@ -0,0 +1,37 @@
+type t<'a>
+
+type value<'a> = {
+  done: bool,
+  value: option<'a>,
+}
+
+let value = v => {
+  done: false,
+  value: Some(v),
+}
+
+let done = (~finalValue=?) => {
+  done: true,
+  value: finalValue,
+}
+
+@send external next: t<'a> => promise<value<'a>> = "next"
+
+let forEach = async (iterator, f) => {
+  let iteratorDone = ref(false)
+
+  while !iteratorDone.contents {
+    let {done, value} = await iterator->next
+    f(value)
+    iteratorDone := done
+  }
+}
+
+let make: (unit => promise<value<'value>>) => t<'value> = %raw(`function makeAsyncIterator(next) {
+  return {
+    next,
+    [Symbol.asyncIterator]() {
+      return this;
+    }
+  }
+}`)
diff --git a/runtime/AsyncIterator.resi b/runtime/AsyncIterator.resi
new file mode 100644
index 0000000000..bbe8de3b09
--- /dev/null
+++ b/runtime/AsyncIterator.resi
@@ -0,0 +1,160 @@
+/***
+Bindings to async iterators, a way to do async iteration in JavaScript.
+
+See [async iterator protocols](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_async_iterator_and_async_iterable_protocols) on MDN.*/
+
+/**
+The type representing an async iterator.
+*/
+type t<'a>
+
+type value<'a> = {
+  /**
+  Whether there are more values to iterate on before the iterator is done.
+  */
+  done: bool,
+  /**
+  The value of this iteration, if any.
+  */
+  value: option<'a>,
+}
+
+/**
+ `make(nextFn)`
+
+  Creates an async iterator from a function that returns the next value of the iterator.
+
+  ## Examples
+  - A simple example, creating an async iterator that returns 1, 2, 3:
+  ```rescript
+  let context = ref(0)
+
+  let asyncIterator = AsyncIterator.make(async () => {
+    let currentValue = context.contents
+    // Increment current value
+    context := currentValue + 1
+    
+    {
+      AsyncIterator.value: Some(currentValue),
+      done: currentValue >= 3
+    }
+  })
+
+  // This will log 1, 2, 3
+  await asyncIterator->AsyncIterator.forEach(value =>
+    switch value {
+    | Some(value) => Console.log(value)
+    | None => ()
+    }
+  )
+  ```
+ */
+let make: (unit => promise<value<'value>>) => t<'value>
+
+/**
+ `value(value)`
+
+ Shorthand for creating a value object with the provided value, and the `done` property set to false.
+
+  ## Examples
+  ```rescript
+  let context = ref(0)
+
+  let asyncIterator = AsyncIterator.make(async () => {
+    let currentValue = context.contents
+    // Increment current value
+    context := currentValue + 1
+    
+    if currentValue >= 3 {
+      AsyncIterator.done()
+    } else {
+      AsyncIterator.value(currentValue)
+    }
+  })
+  ```
+ */
+let value: 'value => value<'value>
+
+/**
+ `done(~finalValue=?)`
+
+ Shorthand for creating a value object with the `done` property set to true, and the provided value as the final value, if any.
+
+  ## Examples
+  ```rescript
+  let context = ref(0)
+
+  let asyncIterator = AsyncIterator.make(async () => {
+    let currentValue = context.contents
+    // Increment current value
+    context := currentValue + 1
+    
+    if currentValue >= 3 {
+      AsyncIterator.done()
+    } else {
+      AsyncIterator.value(currentValue)
+    }
+  })
+  ```
+ */
+let done: (~finalValue: 'value=?) => value<'value>
+
+/**
+`next(asyncIterator)`
+
+Returns the next value of the iterator, if any.
+
+See [async iterator protocols](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_async_iterator_and_async_iterable_protocols) on MDN.
+
+## Examples
+- A simple example, getting the next value:
+```rescript
+@val external asyncIterator: AsyncIterator.t<int> = "someAsyncIterator"
+let value = await asyncIterator->AsyncIterator.next
+```
+
+- Complete example, including looping over all values:
+```rescript
+// Let's pretend we get an async iterator returning ints from somewhere.
+@val external asyncIterator: AsyncIterator.t<int> = "someAsyncIterator"
+
+
+let processMyAsyncIterator = async () => {
+  // ReScript doesn't have `for ... of` loops, but it's easy to mimic using a while loop.
+  let break = ref(false)
+
+  while !break.contents {
+    // Await the next iterator value
+    let {value, done} = await asyncIterator->AsyncIterator.next
+
+    // Exit the while loop if the iterator says it's done
+    break := done
+
+    // This will log the (int) value of the current async iteration, if a value was returned.
+    Console.log(value)
+  }
+}
+```
+*/
+@send
+external next: t<'a> => promise<value<'a>> = "next"
+
+/**
+`forEach(iterator, fn)` consumes all values in the async iterator and runs the callback `fn` for each value.
+
+See [iterator protocols](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols) on MDN.
+
+## Examples
+```rescript
+// Let's pretend we get an async iterator returning ints from somewhere.
+@val external asyncIterator: AsyncIterator.t<int> = "someAsyncIterator"
+
+await asyncIterator->AsyncIterator.forEach(value =>
+  switch value {
+  | Some(value) if value > 10 => Console.log("More than 10!")
+  | _ => ()
+  }
+)
+```
+*/
+let forEach: (t<'a>, option<'a> => unit) => promise<unit>
diff --git a/runtime/BigInt.res b/runtime/BigInt.res
new file mode 100644
index 0000000000..a9fca8a7df
--- /dev/null
+++ b/runtime/BigInt.res
@@ -0,0 +1,97 @@
+@val external asIntN: (~width: int, bigint) => bigint = "BigInt.asIntN"
+@val external asUintN: (~width: int, bigint) => bigint = "BigInt.asUintN"
+
+@val external fromString: string => bigint = "BigInt"
+
+@val
+/**
+Parses the given `string` into a `bigint` using JavaScript semantics. Return the
+number as a `bigint` if successfully parsed. Uncaught syntax exception otherwise.
+
+## Examples
+
+```rescript
+/* returns 123n */
+BigInt.fromStringExn("123")
+
+/* returns 0n */
+BigInt.fromStringExn("")
+
+/* returns 17n */
+BigInt.fromStringExn("0x11")
+
+/* returns 3n */
+BigInt.fromStringExn("0b11")
+
+/* returns 9n */
+BigInt.fromStringExn("0o11")
+
+/* catch exception */
+try {
+  BigInt.fromStringExn("a")
+} catch {
+| Exn.Error(_error) => 0n
+}
+```
+*/
+external fromStringExn: string => bigint = "BigInt"
+@val external fromInt: int => bigint = "BigInt"
+@val external fromFloat: float => bigint = "BigInt"
+
+@send
+/**
+Formats a `bigint` as a string. Return a `string` representing the given value.
+See [`toString`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toString) on MDN.
+
+## Examples
+
+```rescript
+/* prints "123" */
+Js.BigInt.toString(123n)->Js.log
+```
+*/
+external toString: (bigint, ~radix: int=?) => string = "toString"
+
+@deprecated("Use `toString` with `~radix` instead") @send
+external toStringWithRadix: (bigint, ~radix: int) => string = "toString"
+
+@send
+/**
+Returns a string with a language-sensitive representation of this BigInt value.
+
+## Examples
+
+```rescript
+/* prints "123" */
+Js.BigInt.toString(123n)->Js.log
+```
+*/
+external toLocaleString: bigint => string = "toLocaleString"
+
+@val external toFloat: bigint => float = "Number"
+
+let toInt = t => t->toFloat->Int.fromFloat
+
+external \"+": (bigint, bigint) => bigint = "%addbigint"
+external \"-": (bigint, bigint) => bigint = "%subbigint"
+external \"*": (bigint, bigint) => bigint = "%mulbigint"
+external \"/": (bigint, bigint) => bigint = "%divbigint"
+external \"~-": bigint => bigint = "%negbigint"
+external \"~+": bigint => bigint = "%identity"
+external \"**": (bigint, bigint) => bigint = "%powbigint"
+
+external add: (bigint, bigint) => bigint = "%addfloat"
+external sub: (bigint, bigint) => bigint = "%subfloat"
+external mul: (bigint, bigint) => bigint = "%mulfloat"
+external div: (bigint, bigint) => bigint = "%divfloat"
+
+external mod: (bigint, bigint) => bigint = "%modbigint"
+
+external land: (bigint, bigint) => bigint = "%andbigint"
+external lor: (bigint, bigint) => bigint = "%orbigint"
+external lxor: (bigint, bigint) => bigint = "%xorbigint"
+
+external lsl: (bigint, bigint) => bigint = "%lslbigint"
+external asr: (bigint, bigint) => bigint = "%asrbigint"
+
+let lnot = x => lxor(x, -1n)
diff --git a/runtime/BigInt64Array.res b/runtime/BigInt64Array.res
new file mode 100644
index 0000000000..4435a72108
--- /dev/null
+++ b/runtime/BigInt64Array.res
@@ -0,0 +1,53 @@
+/** The `BigInt64Array` typed array represents an array of 64-bit signed integers in platform byte order. See [BigInt64Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt64Array)
+*/
+type t = TypedArray.t<bigint>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "BigInt64Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `BigInt64Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt64Array/BigInt64Array)
+*/
+@new
+external fromArray: array<bigint> => t = "BigInt64Array"
+
+/** `fromBuffer` creates a `BigInt64Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt64Array/BigInt64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "BigInt64Array"
+
+/** `fromBufferToEnd` creates a `BigInt64Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt64Array/BigInt64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "BigInt64Array"
+
+/** `fromBufferWithRange` creates a `BigInt64Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt64Array/BigInt64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "BigInt64Array"
+
+/** `fromLength` creates a zero-initialized `BigInt64Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt64Array/BigInt64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "BigInt64Array"
+
+/** `fromArrayLikeOrIterable` creates a `BigInt64Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "BigInt64Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `BigInt64Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => bigint) => t = "BigInt64Array.from"
diff --git a/runtime/BigUint64Array.res b/runtime/BigUint64Array.res
new file mode 100644
index 0000000000..d9f527d59a
--- /dev/null
+++ b/runtime/BigUint64Array.res
@@ -0,0 +1,54 @@
+/** The `BigUint64Array` typed array represents an array of 64-bit unsigned integers in platform byte order. See [BigUint64Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigUint64Array)
+*/
+type t = TypedArray.t<bigint>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "BigUint64Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `BigUint64Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigUint64Array/BigUint64Array)
+*/
+@new
+external fromArray: array<bigint> => t = "BigUint64Array"
+
+/** `fromBuffer` creates a `BigUint64Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigUint64Array/BigUint64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "BigUint64Array"
+
+/** `fromBufferToEnd` creates a `BigUint64Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigUint64Array/BigUint64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "BigUint64Array"
+
+/** `fromBufferWithRange` creates a `BigUint64Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigUint64Array/BigUint64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t =
+  "BigUint64Array"
+
+/** `fromLength` creates a zero-initialized `BigUint64Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigUint64Array/BigUint64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "BigUint64Array"
+
+/** `fromArrayLikeOrIterable` creates a `BigUint64Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "BigUint64Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `BigUint64Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => bigint) => t = "BigUint64Array.from"
diff --git a/runtime/Console.res b/runtime/Console.res
new file mode 100644
index 0000000000..2c85d0242b
--- /dev/null
+++ b/runtime/Console.res
@@ -0,0 +1,67 @@
+@val external assert_: (bool, 'a) => unit = "console.assert"
+@val external assert2: (bool, 'a, 'b) => unit = "console.assert"
+@val external assert3: (bool, 'a, 'b, 'c) => unit = "console.assert"
+@val external assert4: (bool, 'a, 'b, 'c, 'd) => unit = "console.assert"
+@val external assert5: (bool, 'a, 'b, 'c, 'd, 'e) => unit = "console.assert"
+@val external assert6: (bool, 'a, 'b, 'c, 'd, 'e, 'f) => unit = "console.assert"
+@val @variadic external assertMany: (bool, array<_>) => unit = "console.assert"
+
+@val external clear: unit => unit = "console.clear"
+
+@val external count: string => unit = "console.count"
+@val external countReset: string => unit = "console.countReset"
+
+@val external debug: 'a => unit = "console.debug"
+@val external debug2: ('a, 'b) => unit = "console.debug"
+@val external debug3: ('a, 'b, 'c) => unit = "console.debug"
+@val external debug4: ('a, 'b, 'c, 'd) => unit = "console.debug"
+@val external debug5: ('a, 'b, 'c, 'd, 'e) => unit = "console.debug"
+@val external debug6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.debug"
+@val @variadic external debugMany: array<_> => unit = "console.debug"
+
+@val external dir: 'a => unit = "console.dir"
+@val external dirxml: 'a => unit = "console.dirxml"
+
+@val external error: 'a => unit = "console.error"
+@val external error2: ('a, 'b) => unit = "console.error"
+@val external error3: ('a, 'b, 'c) => unit = "console.error"
+@val external error4: ('a, 'b, 'c, 'd) => unit = "console.error"
+@val external error5: ('a, 'b, 'c, 'd, 'e) => unit = "console.error"
+@val external error6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.error"
+@val @variadic external errorMany: array<_> => unit = "console.error"
+
+@val external group: string => unit = "console.group"
+@val external groupCollapsed: string => unit = "console.groupCollapsed"
+@val external groupEnd: unit => unit = "console.groupEnd"
+
+@val external info: 'a => unit = "console.info"
+@val external info2: ('a, 'b) => unit = "console.info"
+@val external info3: ('a, 'b, 'c) => unit = "console.info"
+@val external info4: ('a, 'b, 'c, 'd) => unit = "console.info"
+@val external info5: ('a, 'b, 'c, 'd, 'e) => unit = "console.info"
+@val external info6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.info"
+@val @variadic external infoMany: array<_> => unit = "console.info"
+
+@val external log: 'a => unit = "console.log"
+@val external log2: ('a, 'b) => unit = "console.log"
+@val external log3: ('a, 'b, 'c) => unit = "console.log"
+@val external log4: ('a, 'b, 'c, 'd) => unit = "console.log"
+@val external log5: ('a, 'b, 'c, 'd, 'e) => unit = "console.log"
+@val external log6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.log"
+@val @variadic external logMany: array<_> => unit = "console.log"
+
+@val external table: 'a => unit = "console.table"
+
+@val external time: string => unit = "console.time"
+@val external timeEnd: string => unit = "console.timeEnd"
+@val external timeLog: string => unit = "console.timeLog"
+
+@val external trace: unit => unit = "console.trace"
+
+@val external warn: 'a => unit = "console.warn"
+@val external warn2: ('a, 'b) => unit = "console.warn"
+@val external warn3: ('a, 'b, 'c) => unit = "console.warn"
+@val external warn4: ('a, 'b, 'c, 'd) => unit = "console.warn"
+@val external warn5: ('a, 'b, 'c, 'd, 'e) => unit = "console.warn"
+@val external warn6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.warn"
+@val @variadic external warnMany: array<_> => unit = "console.warn"
diff --git a/runtime/Console.resi b/runtime/Console.resi
new file mode 100644
index 0000000000..ec1d757ab3
--- /dev/null
+++ b/runtime/Console.resi
@@ -0,0 +1,786 @@
+/***
+Functions for interacting with JavaScript console.
+
+See: [`console`](https://developer.mozilla.org/en-US/docs/Web/API/Console).
+*/
+
+/**
+`assert_(assertion, value)` print a message to console if `assertion` evaluates `false`. Does nothing if it's `true`.
+
+See [`console.assert`](https://developer.mozilla.org/en-US/docs/Web/API/console/assert)
+on MDN.
+
+## Examples
+
+```rescript
+Console.assert_(false, "Hello World!")
+Console.assert_(42 == 42, "The answer")
+```
+*/
+@val
+external assert_: (bool, 'a) => unit = "console.assert"
+
+/**
+`assert2(v1, v2)`. Like `assert_`, but with two arguments.
+
+## Examples
+
+```rescript
+Console.assert2(false, "Hello", "World")
+Console.assert2(42 == 42, [1, 2, 3], '4')
+```
+*/
+@val
+external assert2: (bool, 'a, 'b) => unit = "console.assert"
+
+/**
+`assert3(v1, v2, v3)`. Like `assert_`, but with three arguments.
+
+## Examples
+
+```rescript
+Console.assert3(false, "Hello", "World", "ReScript")
+Console.assert3(42 == 42, "One", 2, #3)
+```
+*/
+@val
+external assert3: (bool, 'a, 'b, 'c) => unit = "console.assert"
+
+/**
+`assert4(v1, v2, v3, v4)`. Like `assert_`, but with four arguments.
+
+## Examples
+
+```rescript
+let value = 42
+Console.assert4(false, "Hello", "World", "ReScript", "!!!")
+Console.assert4(value == 42, [1, 2], (3, 4), [#5, #6], #"polyvar")
+```
+*/
+@val
+external assert4: (bool, 'a, 'b, 'c, 'd) => unit = "console.assert"
+
+/**
+`assert5(v1, v2, v3, v4, v5)`. Like `assert_`, but with five arguments.
+
+## Examples
+
+```rescript
+let value = 42
+Console.assert5(false, "Hello", "World", "JS", '!', '!')
+Console.assert5(value == 42, [1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"})
+```
+*/
+@val
+external assert5: (bool, 'a, 'b, 'c, 'd, 'e) => unit = "console.assert"
+
+/**
+`assert6(v1, v2)`. Like `assert_`, but with six arguments.
+
+## Examples
+
+```rescript
+let value = 42
+Console.assert6(false, "Hello", "World", "JS", '!', '!', '?')
+Console.assert6(value == 42, [1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"}, 42)
+```
+*/
+@val
+external assert6: (bool, 'a, 'b, 'c, 'd, 'e, 'f) => unit = "console.assert"
+
+/**
+`assertMany(assertion, arr)`. Like `assert_`, but variadic.
+
+## Examples
+
+```rescript
+let value = 42
+Console.assertMany(false, ["Hello", "World"])
+Console.assertMany(value == 42, [1, 2, 3])
+```
+*/
+@val
+@variadic
+external assertMany: (bool, array<_>) => unit = "console.assert"
+
+/**
+`clear()` clears the console, if allowed.
+
+See [`console.clear`](https://developer.mozilla.org/en-US/docs/Web/API/console/clear)
+on MDN.
+
+## Examples
+
+```rescript
+Console.clear()
+```
+*/
+@val
+external clear: unit => unit = "console.clear"
+
+/**
+`count(label)` prints to the console the number of times it's been called with the given label.
+
+See [`console.count`](https://developer.mozilla.org/en-US/docs/Web/API/console/count)
+on MDN.
+
+## Examples
+
+```rescript
+Console.count("rescript")
+```
+*/
+@val
+external count: string => unit = "console.count"
+
+/**
+`countReset(label)` resets the count for the given label to 0.
+
+See [`console.countReset`](https://developer.mozilla.org/en-US/docs/Web/API/console/countReset)
+on MDN.
+
+## Examples
+
+```rescript
+Console.countReset("rescript")
+```
+*/
+@val
+external countReset: string => unit = "console.countReset"
+
+/**
+`debug(value)` print a debug message to console.
+
+See [`console.debug`](https://developer.mozilla.org/en-US/docs/Web/API/console/debug)
+on MDN.
+
+## Examples
+
+```rescript
+Console.debug("Hello")
+let obj = {"name": "ReScript", "version": 10}
+Console.debug(obj)
+```
+*/
+@val
+external debug: 'a => unit = "console.debug"
+
+/**
+`debug2(v1, v2)`. Like `debug`, but with two arguments.
+
+## Examples
+
+```rescript
+Console.debug2("Hello", "World")
+Console.debug2([1, 2, 3], '4')
+```
+*/
+@val
+external debug2: ('a, 'b) => unit = "console.debug"
+
+/**
+`debug3(v1, v2, v3)`. Like `debug`, but with three arguments.
+
+## Examples
+
+```rescript
+Console.debug3("Hello", "World", "ReScript")
+Console.debug3("One", 2, #3)
+```
+*/
+@val
+external debug3: ('a, 'b, 'c) => unit = "console.debug"
+
+/**
+`debug4(v1, v2, v3, v4)`. Like `debug`, but with four arguments.
+
+## Examples
+
+```rescript
+Console.debug4("Hello", "World", "ReScript", "!!!")
+Console.debug4([1, 2], (3, 4), [#5, #6], #"polyvar")
+```
+*/
+@val
+external debug4: ('a, 'b, 'c, 'd) => unit = "console.debug"
+
+/**
+`debug5(v1, v2, v3, v4, v5)`. Like `debug`, but with five arguments.
+
+## Examples
+
+```rescript
+Console.debug5("Hello", "World", "JS", '!', '!')
+Console.debug5([1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"})
+```
+*/
+@val
+external debug5: ('a, 'b, 'c, 'd, 'e) => unit = "console.debug"
+
+/**
+`debug6(v1, v2, v3, v4, v5, v6)`. Like `debug`, but with six arguments.
+
+## Examples
+
+```rescript
+Console.debug6("Hello", "World", "JS", '!', '!', '?')
+Console.debug6([1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"}, 42)
+```
+*/
+@val
+external debug6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.debug"
+
+/**
+`debugMany(arr)`. Like `debug`, but variadic.
+
+## Examples
+
+```rescript
+Console.debugMany(["Hello", "World"])
+Console.debugMany([1, 2, 3])
+```
+*/
+@val
+@variadic
+external debugMany: array<_> => unit = "console.debug"
+
+/**
+`dir(object)` displays an interactive view of the object in the console.
+
+See [`console.dir`](https://developer.mozilla.org/en-US/docs/Web/API/console/dir)
+on MDN.
+
+## Examples
+
+```rescript
+Console.dir({"language": "rescript", "version": "10.1.2"})
+```
+*/
+@val
+external dir: 'a => unit = "console.dir"
+
+/**
+`dirxml(object)` displays an interactive tree view of an XML/HTML element in the console.
+
+See [`console.dirxml`](https://developer.mozilla.org/en-US/docs/Web/API/console/dirxml)
+on MDN.
+*/
+@val
+external dirxml: 'a => unit = "console.dirxml"
+
+/**
+`error(value)` prints an error message to console.
+
+See [`console.error`](https://developer.mozilla.org/en-US/docs/Web/API/console/error)
+on MDN.
+
+## Examples
+
+```rescript
+Console.error("error message")
+Console.error(("error", "invalid value"))
+```
+*/
+@val
+external error: 'a => unit = "console.error"
+
+/**
+`error(v1, v2)`. Like `error`, but two arguments.
+
+## Examples
+
+```rescript
+Console.error2("Error", "here")
+Console.error2(("log", "error"), "message")
+```
+*/
+@val
+external error2: ('a, 'b) => unit = "console.error"
+
+/**
+`error3(v1, v2, v3)`. Like `error`, but three arguments.
+
+## Examples
+
+```rescript
+Console.error3("Hello", "World", "!!!")
+Console.error3(#first, #second, #third)
+```
+*/
+@val
+external error3: ('a, 'b, 'c) => unit = "console.error"
+
+/**
+`error4(v1, v2, v3, v4)`. Like `error`, but with four arguments.
+
+## Examples
+
+```rescript
+Console.error4("Hello", "World", "ReScript", '!')
+Console.error4(#first, #second, #third, ("fourth"))
+```
+*/
+@val
+external error4: ('a, 'b, 'c, 'd) => unit = "console.error"
+
+/**
+`error5(v1, v2, v3, v4, v5)`. Like `error`, but with five arguments.
+
+## Examples
+
+```rescript
+Console.error5('e', 'r', 'r', 'o', 'r')
+Console.error5(1, #second, #third, ("fourth"), 'c')
+```
+*/
+@val
+external error5: ('a, 'b, 'c, 'd, 'e) => unit = "console.error"
+
+/**
+`error6(v1, v2, v3, v4, v5, v6)`. Like `error`, but with six arguments.
+
+## Examples
+
+```rescript
+Console.error6("Hello", "World", "from", "JS", "!!!", '!')
+Console.error6([1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"}, 42)
+```
+*/
+@val
+external error6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.error"
+
+/**
+`group(label)` creates a new "group" level with the given label.
+
+See [`console.group`](https://developer.mozilla.org/en-US/docs/Web/API/console/group)
+on MDN.
+
+## Example
+
+```rescript
+Console.group("first group")
+Console.group("second group")
+Console.log("a message on the second level")
+Console.groupEnd()
+Console.log("a message message on the first level")
+Console.groupEnd()
+```
+*/
+@val
+external group: string => unit = "console.group"
+
+/**
+`groupCollapsed(label)`. Like `group` but collapses the group initially.
+
+See [`console.groupCollapsed`](https://developer.mozilla.org/en-US/docs/Web/API/console/groupCollapsed)
+on MDN.
+*/
+@val
+external groupCollapsed: string => unit = "console.groupCollapsed"
+
+/**
+`groupEnd()` ends the current group.
+
+See [`console.groupEnd`](https://developer.mozilla.org/en-US/docs/Web/API/console/groupEnd)
+on MDN.
+*/
+@val
+external groupEnd: unit => unit = "console.groupEnd"
+
+/**
+`errorMany(arr)`. Like `error`, but variadic.
+
+## Examples
+
+```rescript
+Console.errorMany(["Hello", "World"])
+Console.errorMany([1, 2, 3])
+```
+*/
+@val
+@variadic
+external errorMany: array<_> => unit = "console.error"
+
+/**
+`info(value)` print an informational message to console.
+
+See [`console.info`](https://developer.mozilla.org/en-US/docs/Web/API/console/info)
+on MDN.
+
+## Examples
+
+```rescript
+Console.info("Information")
+Console.info(("Hello", "JS"))
+```
+*/
+@val
+external info: 'a => unit = "console.info"
+
+/**
+`info2(v1, v2)`. Like `info`, but with two arguments.
+
+## Examples
+
+```rescript
+Console.info2("Info", "failed to download")
+Console.info2(#info, {"name": "ReScript"})
+```
+*/
+@val
+external info2: ('a, 'b) => unit = "console.info"
+
+/**
+`info3(v1, v2, v3)`. Like `info`, but with three arguments.
+
+## Examples
+
+```rescript
+Console.info3("Hello", "World", "ReScript")
+Console.info3([1, 2, 3], #4, #5)
+```
+*/
+@val
+external info3: ('a, 'b, 'c) => unit = "console.info"
+
+/**
+`info4(v1, v2, v3, v4)`. Like `info`, but with four arguments.
+
+## Examples
+
+```rescript
+Console.info4("Hello", "World", "ReScript", '!')
+Console.info4([1, 2, 3], #4, #5, #lastinfo)
+```
+*/
+@val
+external info4: ('a, 'b, 'c, 'd) => unit = "console.info"
+
+/**
+`info5(v1, v2, v3, v4, v5)`. Like `info`, but with five arguments.
+
+## Examples
+
+```rescript
+Console.info5("Hello", "World", "from", "JS", "!!!")
+Console.info5([1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"})
+```
+*/
+@val
+external info5: ('a, 'b, 'c, 'd, 'e) => unit = "console.info"
+
+/**
+`info6(v1, v2, v3, v4, v5, v6)`. Like `info`, but with six arguments.
+
+## Examples
+
+```rescript
+Console.info6("Hello", "World", "from", "JS", "!!!", '!')
+Console.info6([1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"}, 42)
+```
+*/
+@val
+external info6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.info"
+
+/**
+`infoMany(arr)`. Like `info`, but variadic.
+
+## Examples
+
+```rescript
+Console.infoMany(["Hello", "World"])
+Console.infoMany([1, 2, 3])
+```
+*/
+@val
+@variadic
+external infoMany: array<_> => unit = "console.info"
+
+/**
+`log(value)` print a message to console.
+
+See [`console.log`](https://developer.mozilla.org/en-US/docs/Web/API/console/log)
+on MDN.
+
+## Examples
+
+```rescript
+Console.log("Hello")
+let obj = {"name": "ReScript", "version": 10}
+Console.log(obj)
+```
+*/
+@val
+external log: 'a => unit = "console.log"
+
+/**
+`log2(v1, v2)`. Like `log`, but with two arguments.
+
+## Examples
+
+```rescript
+Console.log2("Hello", "World")
+Console.log2([1, 2, 3], '4')
+```
+*/
+@val
+external log2: ('a, 'b) => unit = "console.log"
+
+/**
+`log3(v1, v2, v3)`. Like `log`, but with three arguments.
+
+## Examples
+
+```rescript
+Console.log3("Hello", "World", "ReScript")
+Console.log3("One", 2, #3)
+```
+*/
+@val
+external log3: ('a, 'b, 'c) => unit = "console.log"
+
+/**
+`log4(v1, v2, v3, v4)`. Like `log`, but with four arguments.
+
+## Examples
+
+```rescript
+Console.log4("Hello", "World", "ReScript", "!!!")
+Console.log4([1, 2], (3, 4), [#5, #6], #"polyvar")
+```
+*/
+@val
+external log4: ('a, 'b, 'c, 'd) => unit = "console.log"
+
+/**
+`log5(v1, v2, v3, v4, v5)`. Like `log`, but with five arguments.
+
+## Examples
+
+```rescript
+Console.log5("Hello", "World", "JS", '!', '!')
+Console.log5([1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"})
+```
+*/
+@val
+external log5: ('a, 'b, 'c, 'd, 'e) => unit = "console.log"
+
+/**
+`log6(v1, v2, v3, v4, v5, v6)`. Like `log`, but with six arguments.
+
+## Examples
+
+```rescript
+Console.log6("Hello", "World", "JS", '!', '!', '?')
+Console.log6([1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"}, 42)
+```
+*/
+@val
+external log6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.log"
+
+/**
+`logMany(arr)`. Like `log`, but variadic.
+
+## Examples
+
+```rescript
+Console.logMany(["Hello", "World"])
+Console.logMany([1, 2, 3])
+```
+*/
+@val
+@variadic
+external logMany: array<_> => unit = "console.log"
+
+/**
+`table(object)` displays an tabular view of the object in the console.
+
+See [`console.table`](https://developer.mozilla.org/en-US/docs/Web/API/console/table)
+on MDN.
+
+## Examples
+
+```rescript
+Console.table({"language": "rescript", "version": "10.1.2"})
+```
+*/
+@val
+external table: 'a => unit = "console.table"
+
+/**
+`time(label)` creates a timer to measure how long an operation takes. `label`
+must be a unique name. Call `console.timeEnd` with the same `label` to print
+output time.
+
+See [`console.time`](https://developer.mozilla.org/en-US/docs/Web/API/console/time)
+on MDN.
+
+## Examples
+
+```rescript
+Console.time("for_time")
+for x in 3 downto 1 {
+  Console.log(x)
+  Console.timeLog("for_time")
+}
+Console.timeEnd("for_time")
+```
+*/
+@val
+external time: string => unit = "console.time"
+
+/**
+`timeEnd(label)` stops a timer created by `time`.
+
+See [`console.timeEnd`](https://developer.mozilla.org/en-US/docs/Web/API/console/timeEnd)
+on MDN.
+
+## Examples
+
+```rescript
+Console.time("for_time")
+for x in 3 downto 1 {
+  Console.log(x)
+  Console.timeLog("for_time")
+}
+Console.timeEnd("for_time")
+```
+*/
+@val
+external timeEnd: string => unit = "console.timeEnd"
+
+/**
+`timeLog(label)` prints the current elapsed time of the given timer to the console.
+
+See [`console.timeLog`](https://developer.mozilla.org/en-US/docs/Web/API/console/timeLog)
+on MDN.
+
+## Examples
+
+```rescript
+Console.time("for_time")
+for x in 3 downto 1 {
+  Console.log(x)
+  Console.timeLog("for_time")
+}
+Console.timeEnd("for_time")
+```
+*/
+@val
+external timeLog: string => unit = "console.timeLog"
+
+/**
+`trace()` print a stack trace to console.
+
+See [`console.trace`](https://developer.mozilla.org/en-US/docs/Web/API/console/trace)
+on MDN.
+
+## Examples
+
+```rescript
+let main = () => {
+  Console.trace()
+}
+main()
+// In the console, the following trace will be displayed:
+// main
+// <anonymous>
+```
+*/
+@val
+external trace: unit => unit = "console.trace"
+
+/**
+`warn(value)` print a warning message to console.
+
+See [`console.warn`](https://developer.mozilla.org/en-US/docs/Web/API/console/warn)
+on MDN.
+
+## Examples
+
+```rescript
+Console.warn("Warning")
+Console.warn(("Warning", "invalid number"))
+```
+*/
+@val
+external warn: 'a => unit = "console.warn"
+
+/**
+`warn2(v1, v2)`. Like `warn`, but two arguments.
+
+## Examples
+
+```rescript
+Console.warn2("Hello", "World")
+Console.warn2([1, 2, 3], 4)
+```
+*/
+@val
+external warn2: ('a, 'b) => unit = "console.warn"
+
+/**
+`warn3(v1, v2, v3)`. Like `warn`, but three arguments.
+
+## Examples
+
+```rescript
+Console.warn3("Hello", "World", "ReScript")
+Console.warn3([1, 2, 3], #4, #5)
+```
+*/
+@val
+external warn3: ('a, 'b, 'c) => unit = "console.warn"
+
+/**
+`warn4(v1, v2, v3, v4)`. Like `warn`, but with four arguments.
+
+## Examples
+
+```rescript
+Console.warn4("Hello", "World", "ReScript", "!!!")
+Console.warn4(#first, #second, #third, ("fourth"))
+```
+*/
+@val
+external warn4: ('a, 'b, 'c, 'd) => unit = "console.warn"
+
+/**
+`warn5(v1, v2, v3, v4, v5)`. Like `warn`, but with five arguments.
+
+## Examples
+
+```rescript
+Console.warn5("Hello", "World", "from", "JS", "!!!")
+Console.warn5([1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"})
+```
+*/
+@val
+external warn5: ('a, 'b, 'c, 'd, 'e) => unit = "console.warn"
+
+/**
+`warn6(v1, v2, v3, v4, v5, v6)`. Like `warn`, but with six arguments.
+
+## Examples
+
+```rescript
+Console.warn6("Hello", "World", "from", "JS", "!!!", '!')
+Console.warn6([1, 2], (3, 4), [#5, #6], #"polyvar", {"name": "ReScript"}, 42)
+```
+*/
+@val
+external warn6: ('a, 'b, 'c, 'd, 'e, 'f) => unit = "console.warn"
+
+/**
+`warnMany(arr)`. Like `warn`, but variadic.
+
+## Examples
+
+```rescript
+Console.warnMany(["Hello", "World"])
+Console.warnMany([1, 2, 3])
+```
+*/
+@val
+@variadic
+external warnMany: array<_> => unit = "console.warn"
diff --git a/runtime/DataView.res b/runtime/DataView.res
new file mode 100644
index 0000000000..8c75a4dff1
--- /dev/null
+++ b/runtime/DataView.res
@@ -0,0 +1,36 @@
+type t
+
+@new external fromBuffer: ArrayBuffer.t => t = "DataView"
+@new external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "DataView"
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "DataView"
+
+@get external buffer: t => ArrayBuffer.t = "buffer"
+@get external byteLength: t => int = "byteLength"
+@get external byteOffset: t => int = "byteOffset"
+
+@send external getInt8: (t, int) => int = "getInt8"
+@send external getUint8: (t, int) => int = "getUint8"
+@send external getInt16: (t, int) => int = "getInt16"
+@send external getUint16: (t, int) => int = "getUint16"
+@send external getInt32: (t, int) => int = "getInt32"
+@send external getUint32: (t, int) => int = "getUint32"
+
+@send external getFloat32: (t, int) => float = "getFloat32"
+@send external getFloat64: (t, int) => float = "getFloat64"
+
+@send external getBigInt64: (t, int) => bigint = "getBigInt64"
+@send external getBigUint64: (t, int) => bigint = "getBigUint64"
+
+@send external setInt8: (t, int, int) => unit = "setInt8"
+@send external setUint8: (t, int, int) => unit = "setUint8"
+@send external setInt16: (t, int, int) => unit = "setInt16"
+@send external setUint16: (t, int, int) => unit = "setUint16"
+@send external setInt32: (t, int, int) => unit = "setInt32"
+@send external setUint32: (t, int, int) => unit = "setUint32"
+
+@send external setFloat32: (t, int, float) => unit = "setFloat32"
+@send external setFloat64: (t, int, float) => unit = "setFloat64"
+
+@send external setBigInt64: (t, int, bigint) => unit = "setBigInt64"
+@send external setBigUint64: (t, int, bigint) => unit = "setBigUint64"
diff --git a/runtime/Date.res b/runtime/Date.res
new file mode 100644
index 0000000000..925afcc190
--- /dev/null
+++ b/runtime/Date.res
@@ -0,0 +1,180 @@
+type t = Js.Date.t
+
+type msSinceEpoch = float
+
+type localeOptions = {
+  dateStyle?: [#full | #long | #medium | #short],
+  timeStyle?: [#full | #long | #medium | #short],
+  weekday?: [#long | #short | #narrow],
+  era?: [#long | #short | #narrow],
+  year?: [#numeric | #"2-digit"],
+  month?: [#numeric | #"2-digit" | #long | #short | #narrow],
+  day?: [#numeric | #"2-digit"],
+  hour?: [#numeric | #"2-digit"],
+  minute?: [#numeric | #"2-digit"],
+  second?: [#numeric | #"2-digit"],
+  timeZoneName?: [#long | #short],
+}
+
+@new external make: unit => t = "Date"
+@new external fromString: string => t = "Date"
+@new external fromTime: msSinceEpoch => t = "Date"
+
+@new external makeWithYM: (~year: int, ~month: int) => t = "Date"
+@new external makeWithYMD: (~year: int, ~month: int, ~date: int) => t = "Date"
+@new external makeWithYMDH: (~year: int, ~month: int, ~date: int, ~hours: int) => t = "Date"
+@new
+external makeWithYMDHM: (~year: int, ~month: int, ~date: int, ~hours: int, ~minutes: int) => t =
+  "Date"
+@new
+external makeWithYMDHMS: (
+  ~year: int,
+  ~month: int,
+  ~date: int,
+  ~hours: int,
+  ~minutes: int,
+  ~seconds: int,
+) => t = "Date"
+@new
+external makeWithYMDHMSM: (
+  ~year: int,
+  ~month: int,
+  ~date: int,
+  ~hours: int,
+  ~minutes: int,
+  ~seconds: int,
+  ~milliseconds: int,
+) => t = "Date"
+
+module UTC = {
+  @val external makeWithYM: (~year: int, ~month: int) => msSinceEpoch = "Date.UTC"
+  @val external makeWithYMD: (~year: int, ~month: int, ~date: int) => msSinceEpoch = "Date.UTC"
+  @val
+  external makeWithYMDH: (~year: int, ~month: int, ~date: int, ~hours: int) => msSinceEpoch =
+    "Date.UTC"
+  @val
+  external makeWithYMDHM: (
+    ~year: int,
+    ~month: int,
+    ~date: int,
+    ~hours: int,
+    ~minutes: int,
+  ) => msSinceEpoch = "Date.UTC"
+  @val
+  external makeWithYMDHMS: (
+    ~year: int,
+    ~month: int,
+    ~date: int,
+    ~hours: int,
+    ~minutes: int,
+    ~seconds: int,
+  ) => msSinceEpoch = "Date.UTC"
+  @val
+  external makeWithYMDHMSM: (
+    ~year: int,
+    ~month: int,
+    ~date: int,
+    ~hours: int,
+    ~minutes: int,
+    ~seconds: int,
+    ~milliseconds: int,
+  ) => msSinceEpoch = "Date.UTC"
+}
+
+@val external now: unit => msSinceEpoch = "Date.now"
+
+@send external getTime: t => msSinceEpoch = "getTime"
+@send external getTimezoneOffset: t => int = "getTimezoneOffset"
+
+let equal = (a, b) => a->getTime === b->getTime
+
+let compare = (a, b) => Float.compare(a->getTime, b->getTime)
+
+// Locale
+@send external getFullYear: t => int = "getFullYear"
+@send external getMonth: t => int = "getMonth"
+@send external getDate: t => int = "getDate"
+@send external getHours: t => int = "getHours"
+@send external getMinutes: t => int = "getMinutes"
+@send external getSeconds: t => int = "getSeconds"
+@send external getMilliseconds: t => int = "getMilliseconds"
+@send external getDay: t => int = "getDay"
+
+@send external setFullYear: (t, int) => unit = "setFullYear"
+@send external setFullYearM: (t, ~year: int, ~month: int) => unit = "setFullYear"
+@send external setFullYearMD: (t, ~year: int, ~month: int, ~date: int) => unit = "setFullYear"
+@send external setMonth: (t, int) => unit = "setMonth"
+@send external setDate: (t, int) => unit = "setDate"
+@send external setHours: (t, int) => unit = "setHours"
+@send external setHoursM: (t, ~hours: int, ~minutes: int) => unit = "setHours"
+@send external setHoursMS: (t, ~hours: int, ~minutes: int, ~seconds: int) => unit = "setHours"
+@send
+external setHoursMSMs: (t, ~hours: int, ~minutes: int, ~seconds: int, ~milliseconds: int) => unit =
+  "setHours"
+@send external setMinutes: (t, int) => unit = "setMinutes"
+@send external setMinutesS: (t, ~minutes: int, ~seconds: int) => unit = "setMinutes"
+@send
+external setMinutesSMs: (t, ~minutes: int, ~seconds: int, ~milliseconds: int) => unit = "setMinutes"
+@send external setSeconds: (t, int) => unit = "setSeconds"
+@send external setSecondsMs: (t, ~seconds: int, ~milliseconds: int) => unit = "setSeconds"
+@send external setMilliseconds: (t, int) => unit = "setMilliseconds"
+
+// UTC
+@send external getUTCFullYear: t => int = "getUTCFullYear"
+@send external getUTCMonth: t => int = "getUTCMonth"
+@send external getUTCDate: t => int = "getUTCDate"
+@send external getUTCHours: t => int = "getUTCHours"
+@send external getUTCMinutes: t => int = "getUTCMinutes"
+@send external getUTCSeconds: t => int = "getUTCSeconds"
+@send external getUTCMilliseconds: t => int = "getUTCMilliseconds"
+@send external getUTCDay: t => int = "getUTCDay"
+
+@send external setUTCFullYear: (t, int) => unit = "setUTCFullYear"
+@send external setUTCFullYearM: (t, ~year: int, ~month: int) => unit = "setUTCFullYear"
+@send
+external setUTCFullYearMD: (t, ~year: int, ~month: int, ~date: int) => unit = "setUTCFullYear"
+@send external setUTCMonth: (t, int) => unit = "setUTCMonth"
+@send external setUTCDate: (t, int) => unit = "setUTCDate"
+@send external setUTCHours: (t, int) => unit = "setUTCHours"
+@send external setUTCHoursM: (t, ~hours: int, ~minutes: int) => unit = "setUTCHours"
+@send
+external setUTCHoursMS: (t, ~hours: int, ~minutes: int, ~seconds: int) => unit = "setUTCHours"
+@send
+external setUTCHoursMSMs: (
+  t,
+  ~hours: int,
+  ~minutes: int,
+  ~seconds: int,
+  ~milliseconds: int,
+) => unit = "setUTCHours"
+@send external setUTCMinutes: (t, int) => unit = "setUTCMinutes"
+@send external setUTCMinutesS: (t, ~minutes: int, ~seconds: int) => unit = "setUTCMinutes"
+@send
+external setUTCMinutesSMs: (t, ~minutes: int, ~seconds: int, ~milliseconds: int) => unit =
+  "setUTCMinutes"
+@send external setUTCSeconds: (t, int) => unit = "setUTCSeconds"
+@send external setUTCSecondsMs: (t, ~seconds: int, ~milliseconds: int) => unit = "setUTCSeconds"
+@send external setUTCMilliseconds: (t, int) => unit = "setUTCMilliseconds"
+
+@send external toDateString: t => string = "toDateString"
+@send external toString: t => string = "toString"
+@send external toTimeString: t => string = "toTimeString"
+
+@send external toLocaleDateString: t => string = "toLocaleDateString"
+@send external toLocaleDateStringWithLocale: (t, string) => string = "toLocaleDateString"
+@send
+external toLocaleDateStringWithLocaleAndOptions: (t, string, localeOptions) => string =
+  "toLocaleDateString"
+@send external toLocaleString: t => string = "toLocaleString"
+@send external toLocaleStringWithLocale: (t, string) => string = "toLocaleString"
+@send
+external toLocaleStringWithLocaleAndOptions: (t, string, localeOptions) => string = "toLocaleString"
+@send external toLocaleTimeString: t => string = "toLocaleTimeString"
+@send external toLocaleTimeStringWithLocale: (t, string) => string = "toLocaleTimeString"
+@send
+external toLocaleTimeStringWithLocaleAndOptions: (t, string, localeOptions) => string =
+  "toLocaleTimeString"
+
+@send external toISOString: t => string = "toISOString"
+@send external toUTCString: t => string = "toUTCString"
+@return(nullable) @send external toJSON: t => option<string> = "toJSON"
diff --git a/runtime/Date.resi b/runtime/Date.resi
new file mode 100644
index 0000000000..f0d975ba1a
--- /dev/null
+++ b/runtime/Date.resi
@@ -0,0 +1,1360 @@
+/***
+  Functions for interacting with JavaScript Dates.
+*/
+
+/**
+A type representing a JavaScript date.
+*/
+type t = Js.Date.t
+
+/**
+Time, in milliseconds, since / until the UNIX epoch (January 1, 1970 00:00:00 UTC).
+Positive numbers represent dates after, negative numbers dates before epoch.
+*/
+type msSinceEpoch = float
+
+/**
+A type representing date time format options.
+
+Note: There are some properties missing:
+- fractionalSecondDigits
+- dayPeriod
+- calendar
+- numberingSystem
+- localeMatcher
+- timeZone
+- hour12
+- hourCycle
+- formatMatcher
+
+See full spec at https://tc39.es/ecma402/#datetimeformat-objects
+*/
+type localeOptions = {
+  dateStyle?: [#full | #long | #medium | #short],
+  timeStyle?: [#full | #long | #medium | #short],
+  weekday?: [#long | #narrow | #short],
+  era?: [#long | #narrow | #short],
+  year?: [#"2-digit" | #numeric],
+  month?: [#"2-digit" | #long | #narrow | #numeric | #short],
+  day?: [#"2-digit" | #numeric],
+  hour?: [#"2-digit" | #numeric],
+  minute?: [#"2-digit" | #numeric],
+  second?: [#"2-digit" | #numeric],
+  timeZoneName?: [#long | #short],
+}
+
+/**
+`make()`
+
+Creates a date object with the current date time as value.
+
+## Examples
+```rescript
+Date.make()
+```
+*/
+@new
+external make: unit => t = "Date"
+
+/**
+`fromString(dateTimeString)`
+
+Creates a date object from given date time string.
+The string has to be in the ISO 8601 format YYYY-MM-DDTHH:mm:ss.sssZ (https://tc39.es/ecma262/#sec-date-time-string-format).
+
+Invalid date time strings will create invalid dates.
+You can use the result like any valid date, but many functions like `toString` will return "Invalid Date" or functions like `Date.getTime` will return NaN.
+
+## Examples
+```rescript
+Date.fromString("2023") // 2023-01-01T00:00:00.000Z
+
+Date.fromString("2023-02-20") // 2023-02-20T00:00:00.000Z
+
+Date.fromString("2023-02-20T16:40:00.00Z") // 2023-02-20T16:40:00.000Z
+
+Date.fromString("") // Invalid Date
+
+Date.fromString("")->Date.getTime // NaN
+```
+*/
+@new
+external fromString: string => t = "Date"
+
+/**
+`fromTime(msSinceEpoch)`
+
+Creates a date object from the given time in milliseconds since / until UNIX epoch (January 1, 1970 00:00:00 UTC).
+Positive numbers create dates after epoch, negative numbers create dates before epoch.
+
+## Examples
+```rescript
+Date.fromTime(0.0)
+// 1970-01-01T00:00:00.000Z
+
+Date.fromTime(-86_400_000.0)
+// 1969-12-31T00:00:00.000Z
+
+Date.fromTime(86_400_000.0)
+// 1970-01-02T00:00:00.000Z
+```
+*/
+@new
+external fromTime: msSinceEpoch => t = "Date"
+
+/**
+Creates a date object with the given year and month.
+Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+Months are 0-indexed (0 = January, 11 = December).
+Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+## Examples
+```rescript
+Date.makeWithYM(~year=2023, ~month=0)
+// 2023-01-01T00:00:00.000Z
+
+Date.makeWithYM(~year=2023, ~month=11)
+// 2023-12-01T00:00:00.000Z
+
+Date.makeWithYM(~year=2023, ~month=12)
+// 2024-01-01T00:00:00.000Z
+
+Date.makeWithYM(~year=2023, ~month=-1)
+// 2022-12-01T00:00:00.000Z
+
+// Note: The output depends on your local time zone.
+// In nodejs you can change it by using the TZ env (`export TZ='Europe/London' && node index.bs.js`)
+
+```
+*/
+@new
+external makeWithYM: (~year: int, ~month: int) => t = "Date"
+
+/**
+Creates a date object with the given year, month and date (day of month).
+Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+Months are 0-indexed (0 = January, 11 = December).
+Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+## Examples
+```rescript
+Date.makeWithYMD(~year=2023, ~month=1, ~date=20)
+// 2023-02-20T00:00:00.000Z
+
+Date.makeWithYMD(~year=2023, ~month=1, ~date=-1)
+// 2022-11-29T00:00:00.000Z
+
+Date.makeWithYMD(~year=2023, ~month=1, ~date=29)
+// 2023-03-01T00:00:00.000Z
+```
+*/
+@new
+external makeWithYMD: (~year: int, ~month: int, ~date: int) => t = "Date"
+
+/**
+Creates a date object with the given year, month, date (day of month) and hours.
+Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+Months are 0-indexed (0 = January, 11 = December).
+Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+## Examples
+```rescript
+Date.makeWithYMDH(~year=2023, ~month=1, ~date=20, ~hours=16)
+// 2023-02-20T16:00:00.000Z
+
+Date.makeWithYMDH(~year=2023, ~month=1, ~date=20, ~hours=24)
+// 2023-02-21T00:00:00.000Z
+
+Date.makeWithYMDH(~year=2023, ~month=1, ~date=20, ~hours=-1)
+// 2023-02-19T23:00:00.000Z
+
+// Note: The output depends on your local time zone.
+// In nodejs you can change it by using the TZ env (`export TZ='Europe/London' && node index.bs.js`)
+
+```
+*/
+@new
+external makeWithYMDH: (~year: int, ~month: int, ~date: int, ~hours: int) => t = "Date"
+
+/**
+Creates a date object with the given year, month, date (day of month), hours and minutes.
+Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+Months are 0-indexed (0 = January, 11 = December).
+Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+## Examples
+```rescript
+Date.makeWithYMDHM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40)
+// 2023-02-20T16:40:00.000Z
+
+Date.makeWithYMDHM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=60)
+// 2023-02-20T17:00:00.000Z
+
+Date.makeWithYMDHM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=-1)
+// 2023-02-20T15:59:00.000Z
+
+// Note: The output depends on your local time zone.
+// In nodejs you can change it by using the TZ env (`export TZ='Europe/London' && node index.bs.js`)
+
+```
+*/
+@new
+external makeWithYMDHM: (~year: int, ~month: int, ~date: int, ~hours: int, ~minutes: int) => t =
+  "Date"
+
+/**
+Creates a date object with the given year, month, date (day of month), hours, minutes and seconds.
+Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+Months are 0-indexed (0 = January, 11 = December).
+Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+## Examples
+```rescript
+Date.makeWithYMDHMS(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=0)
+// 2023-02-20T16:40:00.000Z
+
+Date.makeWithYMDHMS(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=60)
+// 2023-02-20T16:41:00.000Z
+
+Date.makeWithYMDHMS(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=-1)
+// 2023-02-20T16:39:59.000Z
+
+// Note: The output depends on your local time zone.
+// In nodejs you can change it by using the TZ env (`export TZ='Europe/London' && node index.bs.js`)
+
+```
+*/
+@new
+external makeWithYMDHMS: (
+  ~year: int,
+  ~month: int,
+  ~date: int,
+  ~hours: int,
+  ~minutes: int,
+  ~seconds: int,
+) => t = "Date"
+
+/**
+Creates a date object with the given year, month, date (day of month), hours, minutes, seconds and milliseconds.
+Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+Months are 0-indexed (0 = January, 11 = December).
+Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+## Examples
+```rescript
+Date.makeWithYMDHMSM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=0, ~milliseconds=0)
+// 2023-02-20T16:40:00.000Z
+
+Date.makeWithYMDHMSM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=0, ~milliseconds=1000)
+// 2023-02-20T16:40:01.000Z
+
+Date.makeWithYMDHMSM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=0, ~milliseconds=-1)
+// 2023-02-20T16:39:59.999Z
+
+// Note: The output depends on your local time zone.
+// In nodejs you can change it by using the TZ env (`export TZ='Europe/London' && node index.bs.js`)
+
+```
+*/
+@new
+external makeWithYMDHMSM: (
+  ~year: int,
+  ~month: int,
+  ~date: int,
+  ~hours: int,
+  ~minutes: int,
+  ~seconds: int,
+  ~milliseconds: int,
+) => t = "Date"
+module UTC: {
+  /**
+  Returns the time, in milliseconds, since UNIX epoch (January 1, 1970 00:00:00 UTC).
+  Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+  Months are 0-indexed (0 = January, 11 = December).
+  Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+  ## Examples
+  ```rescript
+  Date.UTC.makeWithYM(~year=2023, ~month=0)
+  // 1672531200000
+
+  Date.UTC.makeWithYM(~year=2023, ~month=11)
+  // 1701388800000
+
+  Date.UTC.makeWithYM(~year=2023, ~month=12)
+  // 1704067200000
+
+  Date.UTC.makeWithYM(~year=2023, ~month=-1)
+  // 1669852800000
+  ```
+  */
+  @val
+  external makeWithYM: (~year: int, ~month: int) => msSinceEpoch = "Date.UTC"
+
+  /**
+  Returns the time, in milliseconds, since UNIX epoch (January 1, 1970 00:00:00 UTC).
+  Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+  Months are 0-indexed (0 = January, 11 = December).
+  Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+  ## Examples
+  ```rescript
+  Date.UTC.makeWithYMD(~year=2023, ~month=1, ~date=20)
+  // 1676851200000
+
+  Date.UTC.makeWithYMD(~year=2023, ~month=1, ~date=-1)
+  // 1675036800000
+
+  Date.UTC.makeWithYMD(~year=2023, ~month=1, ~date=29)
+  // 1677628800000
+  ```
+  */
+  @val
+  external makeWithYMD: (~year: int, ~month: int, ~date: int) => msSinceEpoch = "Date.UTC"
+
+  /**
+  Returns the time, in milliseconds, since UNIX epoch (January 1, 1970 00:00:00 UTC).
+  Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+  Months are 0-indexed (0 = January, 11 = December).
+  Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+  ## Examples
+  ```rescript
+  Date.UTC.makeWithYMDH(~year=2023, ~month=1, ~date=20, ~hours=16)
+  // 1676908800000
+
+  Date.UTC.makeWithYMDH(~year=2023, ~month=1, ~date=20, ~hours=24)
+  // 1676937600000
+
+  Date.UTC.makeWithYMDH(~year=2023, ~month=1, ~date=20, ~hours=-1)
+  // 1676847600000
+  ```
+  */
+  @val
+  external makeWithYMDH: (~year: int, ~month: int, ~date: int, ~hours: int) => msSinceEpoch =
+    "Date.UTC"
+
+  /**
+  Returns the time, in milliseconds, since UNIX epoch (January 1, 1970 00:00:00 UTC).
+  Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+  Months are 0-indexed (0 = January, 11 = December).
+  Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+  ## Examples
+  ```rescript
+  Date.UTC.makeWithYMDHM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40)
+  // 1676911200000
+
+  Date.UTC.makeWithYMDHM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=60)
+  // 1676912400000
+
+  Date.UTC.makeWithYMDHM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=-1)
+  // 1676908740000
+  ```
+  */
+  @val
+  external makeWithYMDHM: (
+    ~year: int,
+    ~month: int,
+    ~date: int,
+    ~hours: int,
+    ~minutes: int,
+  ) => msSinceEpoch = "Date.UTC"
+
+  /**
+  Returns the time, in milliseconds, since UNIX epoch (January 1, 1970 00:00:00 UTC).
+  Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+  Months are 0-indexed (0 = January, 11 = December).
+  Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+  ## Examples
+  ```rescript
+  Date.UTC.makeWithYMDHMS(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=0)
+  // 1676911200000
+
+  Date.UTC.makeWithYMDHMS(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=60)
+  // 1676911260000
+
+  Date.UTC.makeWithYMDHMS(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=-1)
+  // 1676911199000
+  ```
+  */
+  @val
+  external makeWithYMDHMS: (
+    ~year: int,
+    ~month: int,
+    ~date: int,
+    ~hours: int,
+    ~minutes: int,
+    ~seconds: int,
+  ) => msSinceEpoch = "Date.UTC"
+
+  /**
+  Returns the time, in milliseconds, since UNIX epoch (January 1, 1970 00:00:00 UTC).
+  Be aware of using a value for year < 100, because it behaves inconsistent (see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#interpretation_of_two-digit_years).
+  Months are 0-indexed (0 = January, 11 = December).
+  Values, which are out of range, will be carried over to the next bigger unit (s. example).
+
+  ## Examples
+  ```rescript
+  Date.UTC.makeWithYMDHMSM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=0, ~milliseconds=0)->Console.log
+  // 1676911200000
+
+  Date.UTC.makeWithYMDHMSM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=0, ~milliseconds=1000)->Console.log
+  // 1676911201000
+
+  Date.UTC.makeWithYMDHMSM(~year=2023, ~month=1, ~date=20, ~hours=16, ~minutes=40, ~seconds=0, ~milliseconds=-1)->Console.log
+  // 1676911199999
+  ```
+  */
+  @val
+  external makeWithYMDHMSM: (
+    ~year: int,
+    ~month: int,
+    ~date: int,
+    ~hours: int,
+    ~minutes: int,
+    ~seconds: int,
+    ~milliseconds: int,
+  ) => msSinceEpoch = "Date.UTC"
+}
+
+/**
+`now()`
+
+Returns the time, in milliseconds, between UNIX epoch (January 1, 1970 00:00:00 UTC) and the current date time.
+*/
+@val
+external now: unit => msSinceEpoch = "Date.now"
+
+let equal: (t, t) => bool
+
+let compare: (t, t) => Ordering.t
+
+/**
+`getTime(date)`
+
+Returns the time, in milliseconds, between UNIX epoch (January 1, 1970 00:00:00 UTC) and the current date time.
+Invalid dates will return NaN.
+Dates before epoch will return negative numbers.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20")->Date.getTime
+// 1676851200000
+```
+*/
+@send
+external getTime: t => msSinceEpoch = "getTime"
+
+/**
+`getTimezoneOffset(date)`
+
+Returns the time in minutes between the UTC time and the locale time.
+The timezone of the given date doesn't matter.
+
+## Examples
+```rescript
+Date.fromString("2023-01-01")->Date.getTimezoneOffset
+// -60 with local time zone = Europe/Berlin
+
+Date.fromString("2023-06-01")->Date.getTimezoneOffset
+// -120 with local time zone = Europe/Berlin
+```
+*/
+@send
+external getTimezoneOffset: t => int = "getTimezoneOffset"
+
+/**
+`getFullYear(date)`
+
+Returns the year of a given date (according to local time).
+
+## Examples
+```rescript
+Date.fromString("2023-02-20")->Date.getFullYear
+// 2023
+```
+*/
+@send
+external getFullYear: t => int = "getFullYear"
+
+/**
+`getMonth(date)`
+
+Returns the month (0-indexed) of a given date (according to local time).
+
+## Examples
+```rescript
+Date.fromString("2023-01-01")->Date.getMonth
+// 0
+```
+*/
+@send
+external getMonth: t => int = "getMonth"
+
+/**
+`getDate(date)`
+
+Returns the date (day of month) of a given date (according to local time).
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.getDate
+// 20
+```
+*/
+@send
+external getDate: t => int = "getDate"
+
+/**
+`getHours(date)`
+
+Returns the hours of a given date (according to local time).
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.getHours
+// 16
+```
+*/
+@send
+external getHours: t => int = "getHours"
+
+/**
+`getMinutes(date)`
+
+Returns the minutes of a given date (according to local time).
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.getMinutes
+// 40
+```
+*/
+@send
+external getMinutes: t => int = "getMinutes"
+
+/**
+`getSeconds(date)`
+
+Returns the seconds of a given date (according to local time).
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.getSeconds
+// 0
+```
+*/
+@send
+external getSeconds: t => int = "getSeconds"
+
+/**
+`getMilliseconds(date)`
+
+Returns the milliseconds of a given date (according to local time).
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.getMilliseconds
+// 0
+```
+*/
+@send
+external getMilliseconds: t => int = "getMilliseconds"
+
+/**
+`getDay(date)`
+
+Returns the day of week of a given date (according to local time).
+0 = Sunday, 1 = Monday, ... 6 = Saturday
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.getDay
+// 1
+```
+*/
+@send
+external getDay: t => int = "getDay"
+
+/**
+`setFullYear(date, year)`
+
+Sets the year of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setFullYear(2024)
+```
+*/
+@send
+external setFullYear: (t, int) => unit = "setFullYear"
+
+/**
+`setFullYearM(date, ~year, ~month)`
+
+Sets the year and month of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setFullYearM(~year=2024, ~month=0)
+```
+*/
+@send
+external setFullYearM: (t, ~year: int, ~month: int) => unit = "setFullYear"
+
+/**
+`setFullYearMD(date, ~year, ~month, ~date)`
+
+Sets the year, month and date (day of month) of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setFullYearMD(~year=2024, ~month=0, ~date=1)
+```
+*/
+@send
+external setFullYearMD: (t, ~year: int, ~month: int, ~date: int) => unit = "setFullYear"
+
+/**
+`setMonth(date, month)`
+
+Sets the month of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setMonth(0)
+```
+*/
+@send
+external setMonth: (t, int) => unit = "setMonth"
+
+/**
+`setDate(date, day)`
+
+Sets the date (day of month) of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setDate(1)
+```
+*/
+@send
+external setDate: (t, int) => unit = "setDate"
+
+/**
+`setHours(date, hours)`
+
+Sets the hours of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setHours(0)
+```
+*/
+@send
+external setHours: (t, int) => unit = "setHours"
+
+/**
+`setHoursM(date, ~hours, ~minutes)`
+
+Sets the hours and minutes of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setHoursM(~hours=0, ~minutes=0)
+```
+*/
+@send
+external setHoursM: (t, ~hours: int, ~minutes: int) => unit = "setHours"
+
+/**
+`setHoursMS(date, ~hours, ~minutes, ~seconds)`
+
+Sets the hours, minutes and seconds of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setHoursMS(~hours=0, ~minutes=0, ~seconds=0)
+```
+*/
+@send
+external setHoursMS: (t, ~hours: int, ~minutes: int, ~seconds: int) => unit = "setHours"
+
+/**
+`setHoursMSMs(date, ~hours, ~minutes, ~seconds, ~milliseconds)`
+
+Sets the hours, minutes, seconds and milliseconds of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setHoursMSMs(~hours=0, ~minutes=0, ~seconds=0, ~milliseconds=0)
+```
+*/
+@send
+external setHoursMSMs: (t, ~hours: int, ~minutes: int, ~seconds: int, ~milliseconds: int) => unit =
+  "setHours"
+
+/**
+`setMinutes(date, minutes)`
+
+Sets the minutes of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setMinutes(0)
+```
+*/
+@send
+external setMinutes: (t, int) => unit = "setMinutes"
+
+/**
+`setMinutesS(date, ~minutes, ~seconds)`
+
+Sets the minutes and seconds of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setMinutesS(~minutes=0, ~seconds=0)
+```
+*/
+@send
+external setMinutesS: (t, ~minutes: int, ~seconds: int) => unit = "setMinutes"
+
+/**
+`setMinutesSMs(date, ~minutes, ~seconds, ~milliseconds)`
+
+Sets the minutes, seconds and milliseconds of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setMinutesSMs(~minutes=0, ~seconds=0, ~milliseconds=0)
+```
+*/
+@send
+external setMinutesSMs: (t, ~minutes: int, ~seconds: int, ~milliseconds: int) => unit = "setMinutes"
+
+/**
+`setSeconds(date, seconds)`
+
+Sets the seconds of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setSeconds(0)
+```
+*/
+@send
+external setSeconds: (t, int) => unit = "setSeconds"
+
+/**
+`setSecondsMs(date, ~seconds, ~milliseconds)`
+
+Sets the seconds and milliseconds of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setSecondsMs(~seconds=0, ~milliseconds=0)
+```
+*/
+@send
+external setSecondsMs: (t, ~seconds: int, ~milliseconds: int) => unit = "setSeconds"
+
+/**
+`setMilliseconds(date, milliseconds)`
+
+Sets the milliseconds of a date (according to local time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setMilliseconds(0)
+```
+*/
+@send
+external setMilliseconds: (t, int) => unit = "setMilliseconds"
+
+/**
+`getUTCFullYear(date)`
+
+Returns the year of a given date (according to UTC time).
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.getUTCFullYear // 2022
+```
+*/
+@send
+external getUTCFullYear: t => int = "getUTCFullYear"
+
+/**
+`getUTCMonth(date)`
+
+Returns the month of a given date (according to UTC time).
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.getUTCMonth // 11
+```
+*/
+@send
+external getUTCMonth: t => int = "getUTCMonth"
+
+/**
+`getUTCDate(date)`
+
+Returns the date (day of month) of a given date (according to UTC time).
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.getUTCDate // 31
+```
+*/
+@send
+external getUTCDate: t => int = "getUTCDate"
+
+/**
+`getUTCHours(date)`
+
+Returns the hours of a given date (according to UTC time).
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.getUTCHours // 23
+```
+*/
+@send
+external getUTCHours: t => int = "getUTCHours"
+
+/**
+`getUTCMinutes(date)`
+
+Returns the minutes of a given date (according to UTC time).
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.getUTCMinutes // 0
+```
+*/
+@send
+external getUTCMinutes: t => int = "getUTCMinutes"
+
+/**
+`getUTCSeconds(date)`
+
+Returns the seconds of a given date (according to UTC time).
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.getUTCSeconds // 0
+```
+*/
+@send
+external getUTCSeconds: t => int = "getUTCSeconds"
+
+/**
+`getUTCMilliseconds(date)`
+
+Returns the milliseconds of a given date (according to UTC time).
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.getUTCMilliseconds // 0
+```
+*/
+@send
+external getUTCMilliseconds: t => int = "getUTCMilliseconds"
+
+/**
+`getUTCDay(date)`
+
+Returns the day (day of week) of a given date (according to UTC time).
+0 = Sunday, 1 = Monday, ... 6 = Saturday
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.getUTCDay // 6
+```
+*/
+@send
+external getUTCDay: t => int = "getUTCDay"
+
+/**
+`setUTCFullYear(date, year)`
+
+Sets the year of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCFullYear(2024)
+```
+*/
+@send
+external setUTCFullYear: (t, int) => unit = "setUTCFullYear"
+
+/**
+`setUTCFullYearM(date, ~year, ~month)`
+
+Sets the year and month of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCFullYearM(~year=2024, ~month=0)
+```
+*/
+@send
+external setUTCFullYearM: (t, ~year: int, ~month: int) => unit = "setUTCFullYear"
+
+/**
+`setUTCFullYearMD(date, ~year, ~month, ~date)`
+
+Sets the year, month and date (day of month) of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCFullYearMD(~year=2024, ~month=0, ~date=1)
+```
+*/
+@send
+external setUTCFullYearMD: (t, ~year: int, ~month: int, ~date: int) => unit = "setUTCFullYear"
+
+/**
+`setUTCMonth(date, month)`
+
+Sets the month of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCMonth(0)
+```
+*/
+@send
+external setUTCMonth: (t, int) => unit = "setUTCMonth"
+
+/**
+`setDate(date, day)`
+
+Sets the date (day of month) of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCDate(1)
+```
+*/
+@send
+external setUTCDate: (t, int) => unit = "setUTCDate"
+
+/**
+`setUTCHours(date, hours)`
+
+Sets the hours of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCHours(0)
+```
+*/
+@send
+external setUTCHours: (t, int) => unit = "setUTCHours"
+
+/**
+`setHoursM(date, ~hours, ~minutes)`
+
+Sets the hours and minutes of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCHoursM(~hours=0, ~minutes=0)
+```
+*/
+@send
+external setUTCHoursM: (t, ~hours: int, ~minutes: int) => unit = "setUTCHours"
+
+/**
+`setUTCHoursMS(date, ~hours, ~minutes, ~seconds)`
+
+Sets the hours, minutes and seconds of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCHoursMS(~hours=0, ~minutes=0, ~seconds=0)
+```
+*/
+@send
+external setUTCHoursMS: (t, ~hours: int, ~minutes: int, ~seconds: int) => unit = "setUTCHours"
+
+/**
+`setUTCHoursMSMs(date, ~hours, ~minutes, ~seconds, ~milliseconds)`
+
+Sets the hours, minutes, seconds and milliseconds of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCHoursMSMs(~hours=0, ~minutes=0, ~seconds=0, ~milliseconds=0)
+```
+*/
+@send
+external setUTCHoursMSMs: (
+  t,
+  ~hours: int,
+  ~minutes: int,
+  ~seconds: int,
+  ~milliseconds: int,
+) => unit = "setUTCHours"
+
+/**
+`setUTCMinutes(date, minutes)`
+
+Sets the minutes of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCMinutes(0)
+```
+*/
+@send
+external setUTCMinutes: (t, int) => unit = "setUTCMinutes"
+
+/**
+`setUTCMinutesS(date, ~minutes, ~seconds)`
+
+Sets the minutes and seconds of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCMinutesS(~minutes=0, ~seconds=0)
+```
+*/
+@send
+external setUTCMinutesS: (t, ~minutes: int, ~seconds: int) => unit = "setUTCMinutes"
+
+/**
+`setUTCMinutesSMs(date, ~minutes, ~seconds, ~milliseconds)`
+
+Sets the minutes, seconds and milliseconds of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCMinutesSMs(~minutes=0, ~seconds=0, ~milliseconds=0)
+```
+*/
+@send
+external setUTCMinutesSMs: (t, ~minutes: int, ~seconds: int, ~milliseconds: int) => unit =
+  "setUTCMinutes"
+
+/**
+`setUTCSeconds(date, seconds)`
+
+Sets the seconds of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCSeconds(0)
+```
+*/
+@send
+external setUTCSeconds: (t, int) => unit = "setUTCSeconds"
+
+/**
+`setUTCSecondsMs(date, ~seconds, ~milliseconds)`
+
+Sets the seconds and milliseconds of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCSecondsMs(~seconds=0, ~milliseconds=0)
+```
+*/
+@send
+external setUTCSecondsMs: (t, ~seconds: int, ~milliseconds: int) => unit = "setUTCSeconds"
+
+/**
+`setUTCMilliseconds(date, milliseconds)`
+
+Sets the milliseconds of a date (according to UTC time).
+Beware this will *mutate* the date.
+
+## Examples
+```rescript
+Date.fromString("2023-02-20T16:40:00.00")->Date.setUTCMilliseconds(0)
+```
+*/
+@send
+external setUTCMilliseconds: (t, int) => unit = "setUTCMilliseconds"
+
+/**
+`toDateString(date)`
+
+Converts a JavaScript date to a standard date string. The date will be mapped to the current time zone.
+If you want to convert it to a localized string, use `Date.toLocaleDateString` instead.
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.toDateString->Console.log
+// Sun Jan 01 2023
+
+Date.fromString("2023-01-01T00:00:00.00+08:00")->Date.toDateString->Console.log
+// Sat Dec 31 2022
+```
+*/
+@send
+external toDateString: t => string = "toDateString"
+
+/**
+`toString(date)`
+
+Converts a JavaScript date to a standard date time string. The date will be mapped to the current time zone.
+If you want to convert it to a localized string, use `Date.toLocaleString` instead.
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.toString->Console.log
+// Sun Jan 01 2023 00:00:00 GMT+0100 (Central European Standard Time)
+
+Date.fromString("2023-06-01T00:00:00.00+01:00")->Date.toString->Console.log
+// Thu Jun 01 2023 01:00:00 GMT+0200 (Central European Summer Time)
+```
+*/
+@send
+external toString: t => string = "toString"
+
+/**
+`toTimeString(date)`
+
+Converts a JavaScript date to a standard time string. The date will be mapped to the current time zone.
+If you want to convert it to a localized string, use `Date.toLocaleStimeString` instead.
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+01:00")->Date.toTimeString->Console.log
+// 00:00:00 GMT+0100 (Central European Standard Time)
+
+Date.fromString("2023-01-01T00:00:00.00+08:00")->Date.toTimeString->Console.log
+// 17:00:00 GMT+0100 (Central European Standard Time)
+```
+*/
+@send
+external toTimeString: t => string = "toTimeString"
+
+/**
+`toLocaleDateString(date)`
+
+Converts a JavaScript date to a localized date string. It will use the current locale.
+
+## Examples
+```rescript
+Date.make()->Date.toLocaleDateString->Console.log
+// 2/19/2023
+```
+*/
+@send
+external toLocaleDateString: t => string = "toLocaleDateString"
+
+/**
+`toLocaleDateStringWithLocale(date, locale)`
+
+Converts a JavaScript date to a localized date string. It will use the specified locale.
+
+## Examples
+```rescript
+Date.make()->Date.toLocaleDateStringWithLocale("en-US")->Console.log
+// 2/19/2023
+```
+*/
+@send
+external toLocaleDateStringWithLocale: (t, string) => string = "toLocaleDateString"
+
+/**
+`toLocaleDateStringWithLocaleAndOptions(date, locale, options)`
+
+Converts a JavaScript date to a localized date string. It will use the specified locale and formatting options.
+
+## Examples
+```rescript
+Date.make()->Date.toLocaleDateStringWithLocaleAndOptions("en-US", { dateStyle: #long })->Console.log
+// February 19, 2023
+
+Date.make()->Date.toLocaleDateStringWithLocaleAndOptions("de", { hour: #"2-digit", minute: #"2-digit" })->Console.log
+// 19.2.2023, 15:40
+
+Date.make()->Date.toLocaleDateStringWithLocaleAndOptions("de", { year: #numeric })->Console.log
+// 2023
+```
+*/
+@send
+external toLocaleDateStringWithLocaleAndOptions: (t, string, localeOptions) => string =
+  "toLocaleDateString"
+
+/**
+`toLocaleString(date)`
+
+Converts a JavaScript date to a localized date-time string. It will use the current locale.
+
+## Examples
+```rescript
+Date.make()->Date.toLocaleString->Console.log
+// 2/19/2023, 3:40:00 PM
+```
+*/
+@send
+external toLocaleString: t => string = "toLocaleString"
+
+/**
+`toLocaleStringWithLocale(date, locale)`
+
+Converts a JavaScript date to a localized date-time string. It will use the specified locale.
+
+## Examples
+```rescript
+Date.make()->Date.toLocaleStringWithLocale("en-US")->Console.log
+// 2/19/2023, 3:40:00 PM
+```
+*/
+@send
+external toLocaleStringWithLocale: (t, string) => string = "toLocaleString"
+
+/**
+`toLocaleStringWithLocaleAndOptions(date, locale, options)`
+
+Converts a JavaScript date to a localized date-time string. It will use the specified locale and formatting options.
+
+## Examples
+```rescript
+Date.make()->Date.toLocaleStringWithLocaleAndOptions("en", { dateStyle: #short, timeStyle: #short })->Console.log
+// 2/19/23, 3:40 PM
+
+Date.make()->Date.toLocaleStringWithLocaleAndOptions("en", { era: #long, year: #numeric, month: #"2-digit", day: #"2-digit", hour: #numeric, timeZoneName: #short })->Console.log
+// 02/19/2023 Anno Domini, 3 PM GMT+1
+```
+*/
+@send
+external toLocaleStringWithLocaleAndOptions: (t, string, localeOptions) => string = "toLocaleString"
+
+/**
+`toLocaleTimeString(date)`
+
+Converts a JavaScript date to a localized time string. It will use the current locale.
+
+## Examples
+```rescript
+Date.make()->Date.toLocaleTimeString->Console.log
+// 3:40:00 PM
+```
+*/
+@send
+external toLocaleTimeString: t => string = "toLocaleTimeString"
+
+/**
+`toLocaleTimeStringWithLocale(date, locale)`
+
+Converts a JavaScript date to a localized time string. It will use the specified locale.
+
+## Examples
+```rescript
+Date.make()->Date.toLocaleTimeStringWithLocale("en-US")->Console.log
+// 3:40:00 PM
+```
+*/
+@send
+external toLocaleTimeStringWithLocale: (t, string) => string = "toLocaleTimeString"
+
+/**
+`toLocaleTimeStringWithLocaleAndOptions(date, locale, options)`
+
+Converts a JavaScript date to a localized time string. It will use the specified locale and formatting options.
+
+## Examples
+```rescript
+Date.make()->Date.toLocaleTimeStringWithLocaleAndOptions("en-US", { timeStyle: #long })->Console.log
+// 3:40:00 PM GMT+1
+
+Date.make()->Date.toLocaleTimeStringWithLocaleAndOptions("de", { hour: #"2-digit", minute: #"2-digit" })->Console.log
+// 15:40
+```
+*/
+@send
+external toLocaleTimeStringWithLocaleAndOptions: (t, string, localeOptions) => string =
+  "toLocaleTimeString"
+
+/**
+`toISOString(date)`
+
+Converts a JavaScript date to a ISO 8601 string (YYYY-MM-DDTHH:mm:ss.sssZ). The date will be mapped to the UTC time.
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+00:00")->Date.toISOString->Console.log
+// 2023-01-01T00:00:00.000Z
+
+Date.fromString("2023-01-01T00:00:00.00+08:00")->Date.toISOString->Console.log
+// 2022-12-31T16:00:00.000Z
+```
+*/
+@send
+external toISOString: t => string = "toISOString"
+
+/**
+`toUTCString(date)`
+
+Converts a JavaScript date to date time string. The date will be mapped to the UTC time.
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+00:00")->Date.toUTCString->Console.log
+// Sun, 01 Jan 2023 00:00:00 GMT
+
+Date.fromString("2023-01-01T00:00:00.00+08:00")->Date.toUTCString->Console.log
+// Sat, 31 Dec 2022 16:00:00 GMT
+```
+*/
+@send
+external toUTCString: t => string = "toUTCString"
+
+/**
+`toJSON(date)`
+
+Converts a JavaScript date to a string.
+If the date is valid, the function will return the same result as `Date.toISOString`.
+Invalid dates will return `None`.
+
+## Examples
+```rescript
+Date.fromString("2023-01-01T00:00:00.00+00:00")->Date.toJSON
+// Some("2023-01-01T00:00:00.000Z")
+
+Date.fromString("")->Date.toJSON
+// None
+```
+*/
+@return(nullable)
+@send
+external toJSON: t => option<string> = "toJSON"
diff --git a/runtime/Dict.res b/runtime/Dict.res
new file mode 100644
index 0000000000..c56ecdc783
--- /dev/null
+++ b/runtime/Dict.res
@@ -0,0 +1,41 @@
+type t<'a> = Js.Dict.t<'a>
+
+@get_index external getUnsafe: (t<'a>, string) => 'a = ""
+@get_index external get: (t<'a>, string) => option<'a> = ""
+@set_index external set: (t<'a>, string, 'a) => unit = ""
+@val external delete: 'a => unit = "delete"
+
+let delete = (dict, string) => {
+  delete(get(dict, string))
+}
+
+@obj external make: unit => t<'a> = ""
+
+@val external fromArray: array<(string, 'a)> => t<'a> = "Object.fromEntries"
+@val external fromIterator: Iterator.t<(string, 'a)> => t<'a> = "Object.fromEntries"
+
+@val external toArray: t<'a> => array<(string, 'a)> = "Object.entries"
+
+@val external keysToArray: t<'a> => array<string> = "Object.keys"
+
+@val external valuesToArray: t<'a> => array<'a> = "Object.values"
+
+@val external assign: (t<'a>, t<'a>) => t<'a> = "Object.assign"
+
+@val external copy: (@as(json`{}`) _, t<'a>) => t<'a> = "Object.assign"
+
+let forEach = (dict, f) => {
+  dict->valuesToArray->Array.forEach(value => f(value))
+}
+
+let forEachWithKey = (dict, f) => {
+  dict->toArray->Array.forEach(((key, value)) => f(value, key))
+}
+
+let mapValues = (dict, f) => {
+  let target = make()
+  dict->forEachWithKey((value, key) => {
+    target->set(key, f(value))
+  })
+  target
+}
diff --git a/runtime/Dict.resi b/runtime/Dict.resi
new file mode 100644
index 0000000000..2850a12d20
--- /dev/null
+++ b/runtime/Dict.resi
@@ -0,0 +1,234 @@
+/***
+A mutable dictionary with string keys.
+
+Compiles to a regular JavaScript object.*/
+
+/**
+Type representing a dictionary of value `'a`.
+*/
+type t<'a> = Js.Dict.t<'a>
+
+/**
+`getUnsafe(dict, key)` Returns the `value` at the provided `key`.
+
+This is _unsafe_, meaning it will return `undefined` value if `key` does not exist in `dict`.
+
+Use `Dict.getUnsafe` only when you are sure the key exists (i.e. when iterating `Dict.keys` result).
+
+## Examples
+```rescript
+let dict = Dict.fromArray([("key1", "value1"), ("key2", "value2")])
+let value = dict->Dict.getUnsafe("key1")
+Console.log(value) // value1
+```
+*/
+@get_index
+external getUnsafe: (t<'a>, string) => 'a = ""
+
+/**
+Returns the value at the provided key, if it exists. Returns an option.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([("someKey", "someValue")])
+
+switch dict->Dict.get("someKey") {
+| None => Console.log("Nope, didn't have the key.")
+| Some(value) => Console.log(value)
+}
+```
+*/
+@get_index
+external get: (t<'a>, string) => option<'a> = ""
+
+/**
+`set(dictionary, key, value)` sets the value at the provided key to the provided value.
+
+## Examples
+```rescript
+let dict = Dict.make()
+
+dict->Dict.set("someKey", "someValue")
+```
+*/
+@set_index
+external set: (t<'a>, string, 'a) => unit = ""
+
+/**
+`delete(dictionary, key)` deletes the value at `key`, if it exists.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([("someKey", "someValue")])
+
+dict->Dict.delete("someKey")
+```
+*/
+let delete: (t<'a>, string) => unit
+
+/**
+`make()` creates a new, empty dictionary.
+
+## Examples
+```rescript
+let dict1: Dict.t<int> = Dict.make() // You can annotate the type of the values of your dict yourself if you want
+
+let dict2 = Dict.make() // Or you can let ReScript infer it via usage.
+dict2->Dict.set("someKey", 12)
+```
+*/
+@obj
+external make: unit => t<'a> = ""
+
+/**
+`fromArray(entries)` creates a new dictionary from the provided array of key/value pairs.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([("key1", "value1"), ("key2", "value2")])
+```
+*/
+@val
+external fromArray: array<(string, 'a)> => t<'a> = "Object.fromEntries"
+
+/**
+`fromIterator(entries)` creates a new dictionary from the provided iterator of key/value pairs.
+
+## Examples
+```rescript
+// Pretend we have an iterator of the correct shape
+@val external someIterator: Iterator.t<(string, int)> = "someIterator"
+
+let dict = Dict.fromIterator(someIterator) // Dict.t<int>
+```
+*/
+@val
+external fromIterator: Iterator.t<(string, 'a)> => t<'a> = "Object.fromEntries"
+
+/**
+`toArray(dictionary)` returns an array of all the key/value pairs of the dictionary.
+
+## Examples
+```rescript
+let dict = Dict.make()
+dict->Dict.set("someKey", 1)
+dict->Dict.set("someKey2", 2)
+let asArray = dict->Dict.toArray
+Console.log(asArray) // Logs `[["someKey", 1], ["someKey2", 2]]` to the console
+```
+*/
+@val
+external toArray: t<'a> => array<(string, 'a)> = "Object.entries"
+
+/**
+`keysToArray(dictionary)` returns an array of all the keys of the dictionary.
+
+## Examples
+```rescript
+let dict = Dict.make()
+dict->Dict.set("someKey", 1)
+dict->Dict.set("someKey2", 2)
+let keys = dict->Dict.keysToArray
+Console.log(keys) // Logs `["someKey", "someKey2"]` to the console
+```
+*/
+@val
+external keysToArray: t<'a> => array<string> = "Object.keys"
+
+/**
+`valuesToArray(dictionary)` returns an array of all the values of the dictionary.
+
+## Examples
+```rescript
+let dict = Dict.make()
+dict->Dict.set("someKey", 1)
+dict->Dict.set("someKey2", 2)
+let values = dict->Dict.valuesToArray
+Console.log(values) // Logs `[1, 2]` to the console
+```
+*/
+@val
+external valuesToArray: t<'a> => array<'a> = "Object.values"
+
+/**
+`assign(dictionary1, dictionary2)` [shallowly](https://developer.mozilla.org/en-US/docs/Glossary/Shallow_copy) merges dictionary2 into dictionary1, and returns dictionary1.
+
+Beware this will *mutate* dictionary1. If you're looking for a way to copy a dictionary, check out `Dict.copy`.
+
+## Examples
+```rescript
+let dict1 = Dict.make()
+dict1->Dict.set("firstKey", 1)
+Console.log(dict1->Dict.keysToArray) // Logs `["firstKey"]`
+
+let dict2 = Dict.make()
+dict2->Dict.set("someKey", 2)
+dict2->Dict.set("someKey2", 3)
+
+let dict1 = dict1->Dict.assign(dict2)
+
+Console.log(dict1->Dict.keysToArray) // Logs `["firstKey", "someKey", "someKey2"]`
+
+```
+*/
+@val
+external assign: (t<'a>, t<'a>) => t<'a> = "Object.assign"
+
+/**
+`copy(dictionary)` [shallowly copies](https://developer.mozilla.org/en-US/docs/Glossary/Shallow_copy) the provided dictionary to a new dictionary.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([("key1", "value1"), ("key2", "value2")])
+let dict2 = dict->Dict.copy
+
+// Both log `["key1", "key2"]` here.
+Console.log2(dict->Dict.keysToArray, dict2->Dict.keysToArray)
+```
+*/
+@val
+external copy: (@as(json`{}`) _, t<'a>) => t<'a> = "Object.assign"
+
+/**
+`forEach(dictionary, f)` iterates through all values of the dict.
+
+> Please note that this is *without the keys*, just the values. If you need the key as well, use `Dict.forEachWithKey`.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([("key1", "value1"), ("key2", "value2")])
+
+dict->Dict.forEach(value => {
+  Console.log(value)
+})
+```
+*/
+let forEach: (t<'a>, 'a => unit) => unit
+
+/**
+`forEachWithKey(dictionary, f)` iterates through all values of the dict, including the key for each value.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([("key1", "value1"), ("key2", "value2")])
+
+dict->Dict.forEachWithKey((value, key) => {
+  Console.log2(value, key)
+})
+```
+*/
+let forEachWithKey: (t<'a>, ('a, string) => unit) => unit
+
+/**
+`mapValues(dictionary, f)` returns a new dictionary with the same keys, and `f` applied to each value in the original dictionary.
+
+## Examples
+
+```rescript
+let dict = Dict.fromArray([("key1", 1), ("key2", 2)])
+
+dict->Dict.mapValues(v => v + 10)->Dict.toArray // [("key1", 11), ("key2", 12)]
+dict->Dict.mapValues(v => Int.toString(v))->Dict.toArray // [("key1", "1"), ("key2", "2")]
+```
+*/
+let mapValues: (t<'a>, 'a => 'b) => t<'b>
diff --git a/runtime/Error.res b/runtime/Error.res
new file mode 100644
index 0000000000..408b08ff56
--- /dev/null
+++ b/runtime/Error.res
@@ -0,0 +1,39 @@
+type t = Js.Exn.t
+
+external fromException: exn => option<t> = "?as_js_exn"
+external toException: t => exn = "%identity"
+
+@get external stack: t => option<string> = "stack"
+@get external message: t => option<string> = "message"
+@get external name: t => option<string> = "name"
+@get external fileName: t => option<string> = "fileName"
+
+@new external make: string => t = "Error"
+
+module EvalError = {
+  @new external make: string => t = "EvalError"
+}
+
+module RangeError = {
+  @new external make: string => t = "RangeError"
+}
+
+module ReferenceError = {
+  @new external make: string => t = "ReferenceError"
+}
+
+module SyntaxError = {
+  @new external make: string => t = "SyntaxError"
+}
+
+module TypeError = {
+  @new external make: string => t = "TypeError"
+}
+
+module URIError = {
+  @new external make: string => t = "URIError"
+}
+
+external raise: t => 'a = "%raise"
+
+let panic = msg => make(`Panic! ${msg}`)->raise
diff --git a/runtime/Error.resi b/runtime/Error.resi
new file mode 100644
index 0000000000..38b6a97334
--- /dev/null
+++ b/runtime/Error.resi
@@ -0,0 +1,172 @@
+/***
+Functions for working with JavaScript exceptions.
+
+See [`Error`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error) on MDN.
+*/
+
+/** Represents a JavaScript exception. */
+type t = Js.Exn.t
+
+external fromException: exn => option<t> = "?as_js_exn"
+
+/**
+Turns an `Error.t` into an `exn`.
+
+## Examples
+```rescript
+let error = Error.make("Something went wrong.")
+
+let asExn = error->Error.toException // `asExn` is now type `exn`
+```
+*/
+external toException: t => exn = "%identity"
+
+/**
+`stack(error)` retrieves the `stack` property of the error, if it exists. The stack is a list of what functions were called, and what files they are defined in, prior to the error happening.
+
+See [`Error.prototype.stack`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/Stack) on MDN.
+
+## Example
+```rescript
+let error = Error.make("error")
+Console.log(error->Error.stack) // Logs `stack` if it exists on `someError`
+```
+*/
+@get
+external stack: t => option<string> = "stack"
+
+/**
+`message(error)` retrieves the `message` property of the error, if it exists.
+
+See [`Error.prototype.message`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/message) on MDN.
+
+## Example
+```rescript
+let error = Error.SyntaxError.make("Some message here")
+Console.log(error->Error.message) // Logs "Some message here" to the console
+```
+*/
+@get
+external message: t => option<string> = "message"
+
+/**
+`name(error)` retrieves the `name` property of the error, if it exists.
+
+See [`Error.prototype.name`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/name) on MDN.
+
+## Example
+```rescript
+let error = Error.SyntaxError.make("Some message here")
+Console.log(error->Error.name) // Logs "SyntaxError" to the console
+```
+*/
+@get
+external name: t => option<string> = "name"
+
+/**
+`fileName(error)` retrieves the `fileName` property of the error, if it exists.
+
+See [`Error.prototype.fileName`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/fileName) on MDN.
+*/
+@get
+external fileName: t => option<string> = "fileName"
+
+/**
+`make(message)` creates a new error, setting its `message` to the provided value.
+
+See [`Error`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/Error) on MDN.
+
+## Example
+```rescript
+let error = Error.make("Some message here")
+Console.log(error->Error.message) // Logs "Some message here" to the console
+Console.log(error->Error.name) // Logs "Error" to the console, because this is a regular error
+```
+*/
+@new
+external make: string => t = "Error"
+
+module EvalError: {
+  /**
+  Creates a new `EvalError` with the provided `message`.
+
+  See [`EvalError`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/EvalError) on MDN.
+  */
+  @new
+  external make: string => t = "EvalError"
+}
+module RangeError: {
+  /**
+  Creates a new `RangeError` with the provided `message`.
+
+  See [`RangeError`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RangeError) on MDN.
+  */
+  @new
+  external make: string => t = "RangeError"
+}
+module ReferenceError: {
+  /**
+  Creates a new `ReferenceError` with the provided `message`.
+
+  See [`ReferenceError`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ReferenceError) on MDN.
+  */
+  @new
+  external make: string => t = "ReferenceError"
+}
+module SyntaxError: {
+  /**
+  Creates a new `SyntaxError` with the provided `message`.
+
+  See [`SyntaxError`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SyntaxError) on MDN.
+  */
+  @new
+  external make: string => t = "SyntaxError"
+}
+module TypeError: {
+  /**
+  Creates a new `TypeError` with the provided `message`.
+
+  See [`TypeError`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypeError) on MDN.
+  */
+  @new
+  external make: string => t = "TypeError"
+}
+module URIError: {
+  /**
+  Creates a new `URIError` with the provided `message`.
+
+  See [`URIError`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/URIError) on MDN.
+  */
+  @new
+  external make: string => t = "URIError"
+}
+
+/**
+Raises (throws in JavaScript language) the provided `Error.t`, which will stop execution.
+
+## Examples
+```rescript
+let error = Error.make("Everything is upside down.")
+
+if 5 > 10 {
+  error->Error.raise
+} else {
+  Console.log("Phew, sanity still rules.")
+}
+```
+*/
+external raise: t => 'a = "%raise"
+
+/**
+Raises a panic exception with the given message.
+
+A panic exception is a native JavaScript exception that is not intended to be caught and
+handled. Compared to a ReScript exception this will give a better stack trace and
+debugging experience.
+
+## Examples
+```rescript
+Error.panic("Uh oh. This was unexpected!")
+```
+*/
+let panic: string => 'a
diff --git a/runtime/Js_exn.res b/runtime/Exn.res
similarity index 100%
rename from runtime/Js_exn.res
rename to runtime/Exn.res
diff --git a/runtime/Js_exn.resi b/runtime/Exn.resi
similarity index 100%
rename from runtime/Js_exn.resi
rename to runtime/Exn.resi
diff --git a/runtime/Float.res b/runtime/Float.res
new file mode 100644
index 0000000000..8c7c2ad60c
--- /dev/null
+++ b/runtime/Float.res
@@ -0,0 +1,59 @@
+module Constants = {
+  @val external nan: float = "NaN"
+  @val external epsilon: float = "Number.EPSILON"
+  @val external positiveInfinity: float = "Number.POSITIVE_INFINITY"
+  @val external negativeInfinity: float = "Number.NEGATIVE_INFINITY"
+  @val external minValue: float = "Number.MIN_VALUE"
+  @val external maxValue: float = "Number.MAX_VALUE"
+}
+
+external equal: (float, float) => bool = "%equal"
+
+external compare: (float, float) => Ordering.t = "%compare"
+
+@val external isNaN: float => bool = "isNaN"
+@val external isFinite: float => bool = "isFinite"
+@val external parseFloat: 'a => float = "parseFloat"
+// parseInt's return type is a float because it can be NaN
+@val external parseInt: ('a, ~radix: int=?) => float = "parseInt"
+@deprecated("Use `parseInt` instead") @val
+external parseIntWithRadix: ('a, ~radix: int) => float = "parseInt"
+
+@send external toExponential: (float, ~digits: int=?) => string = "toExponential"
+@deprecated("Use `toExponential` instead") @send
+external toExponentialWithPrecision: (float, ~digits: int) => string = "toExponential"
+
+@send external toFixed: (float, ~digits: int=?) => string = "toFixed"
+@deprecated("Use `toFixed` instead") @send
+external toFixedWithPrecision: (float, ~digits: int) => string = "toFixed"
+
+@send external toPrecision: (float, ~digits: int=?) => string = "toPrecision"
+@deprecated("Use `toPrecision` instead") @send
+external toPrecisionWithPrecision: (float, ~digits: int) => string = "toPrecision"
+
+@send external toString: (float, ~radix: int=?) => string = "toString"
+@deprecated("Use `toString` instead") @send
+external toStringWithRadix: (float, ~radix: int) => string = "toString"
+@send external toLocaleString: float => string = "toLocaleString"
+
+let fromString = i =>
+  switch parseFloat(i) {
+  | i if isNaN(i) => None
+  | i => Some(i)
+  }
+
+external toInt: float => int = "%intoffloat"
+external fromInt: int => float = "%identity"
+
+@unboxed @noalloc external mod: (float, float) => float = "?fmod_float"
+
+let clamp = (~min=?, ~max=?, value): float => {
+  let value = switch max {
+  | Some(max) if max < value => max
+  | _ => value
+  }
+  switch min {
+  | Some(min) if min > value => min
+  | _ => value
+  }
+}
diff --git a/runtime/Float.resi b/runtime/Float.resi
new file mode 100644
index 0000000000..6569aef560
--- /dev/null
+++ b/runtime/Float.resi
@@ -0,0 +1,459 @@
+/* Copyright (C) 2015-2016 Bloomberg Finance L.P.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/***
+Functions for interacting with float.
+*/
+
+/**
+Float constants.
+*/
+module Constants: {
+  /**
+  The special value "Not a Number"
+  See [`NaN`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/NaN) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Float.Constants.nan
+  ```
+  */
+  @val
+  external nan: float = "NaN"
+
+  /**
+  Represents the difference between 1 and the smallest floating point number greater than 1.
+  See [`Number.EPSILON`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/EPSILON) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Float.Constants.epsilon
+  ```
+  */
+  @val
+  external epsilon: float = "Number.EPSILON"
+
+  /**
+  The positive Infinity value
+  See [`Number.POSITIVE_INFINITY`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/POSITIVE_INFINITY) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Float.Constants.positiveInfinity
+  ```
+  */
+  @val
+  external positiveInfinity: float = "Number.POSITIVE_INFINITY"
+
+  /**
+  The negative Infinity value
+  See [`Number.NEGATIVE_INFINITY`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/NEGATIVE_INFINITY) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Float.Constants.negativeInfinity
+  ```
+  */
+  @val
+  external negativeInfinity: float = "Number.NEGATIVE_INFINITY"
+
+  /**
+  The smallest positive numeric value representable in JavaScript.
+  See [`Number.MIN_VALUE`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MIN_VALUE) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Float.Constants.minValue
+  ```
+  */
+  @val
+  external minValue: float = "Number.MIN_VALUE"
+
+  /**
+  The maximum positive numeric value representable in JavaScript.
+  See [`Number.MAX_VALUE`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_VALUE) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Float.Constants.minValue
+  ```
+  */
+  @val
+  external maxValue: float = "Number.MAX_VALUE"
+}
+
+external equal: (float, float) => bool = "%equal"
+
+external compare: (float, float) => Ordering.t = "%compare"
+
+/**
+`isNaN(v)` tests if the given `v` is `NaN`.
+See [`NaN`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/NaN) on MDN.
+
+## Examples
+
+```rescript
+Float.isNaN(3.0) // false
+Float.isNaN(Float.Constants.nan) // true
+```
+*/
+@val
+external isNaN: float => bool = "isNaN"
+
+/**
+`isFinite(v)` tests if the given `v` is finite.
+See [`isFinite`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isFinite) on MDN.
+
+## Examples
+
+```rescript
+Float.isFinite(1.0) // true
+Float.isFinite(Float.Constants.nan) // false
+Float.isFinite(Float.Constants.positiveInfinity) // false
+```
+*/
+@val
+external isFinite: float => bool = "isFinite"
+
+/**
+`parseFloat(v)` parse the given `v` and returns a float. Leading whitespace in
+`v` is ignored. Returns `NaN` if `v` can't be parsed. Use [`fromString`] to
+ensure it returns a valid float and not `NaN`.
+See [`parseFloat`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseFloat) on MDN.
+
+## Examples
+
+```rescript
+Float.parseFloat("1.0") // 1.0
+Float.parseFloat("  3.14   ") // 3.14
+Float.parseFloat("3.0") // 3.0
+Float.parseFloat("3.14some non-digit characters") // 3.14
+Float.parseFloat("error")->Float.isNaN // true
+```
+*/
+@val
+external parseFloat: string => float = "parseFloat"
+
+/**
+`parseInt(v, ~radix=?)` parse the given `v` and returns a float. Leading
+whitespace in this argument `v`is ignored. `radix` specifies the radix base to
+use for the formatted number. The value must be in the range [2, 36] (inclusive).
+Returns `NaN` if `v` can't be parsed and `radix` is smaller than 2 or bigger
+than 36.
+See [`parseInt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt) on MDN.
+
+## Examples
+
+```rescript
+Float.parseInt("1.0") // 1.0
+Float.parseInt("  3.14   ") // 3.0
+Float.parseInt(3) // 3.0
+Float.parseInt("3.14some non-digit characters") // 3.0
+Float.parseInt("error")->Float.isNaN // true
+Float.parseInt("10.0", ~radix=2) // 2.0
+Float.parseInt("15 * 3", ~radix=10) // 15.0
+Float.parseInt("12", ~radix=13) // 15.0
+Float.parseInt("17", ~radix=40)->Float.isNaN // true
+```
+*/
+@val
+external parseInt: ('a, ~radix: int=?) => float = "parseInt"
+
+/**
+`parseIntWithRadix(v, ~radix)` parse the given `v` and returns a float. Leading
+whitespace in this argument `v`is ignored. `radix` specifies the radix base to
+use for the formatted number. The value must be in the range [2, 36] (inclusive).
+Returns `NaN` if `v` can't be parsed and `radix` is smaller than 2 or bigger
+than 36.
+See [`parseInt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt) on MDN.
+
+## Examples
+
+```rescript
+Float.parseIntWithRadix("10.0", ~radix=2) // 2.0
+Float.parseIntWithRadix("15 * 3", ~radix=10) // 15.0
+Float.parseIntWithRadix("12", ~radix=13) // 15.0
+Float.parseIntWithRadix("17", ~radix=40)->Float.isNaN // true
+```
+*/
+@deprecated("Use `parseInt` instead")
+@val
+external parseIntWithRadix: ('a, ~radix: int) => float = "parseInt"
+
+/**
+`toExponential(v, ~digits=?)` return a `string` representing the given value in
+exponential notation. `digits` specifies how many digits should appear after
+the decimal point.
+See [`Number.toExponential`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toExponential) on MDN.
+
+## Examples
+
+```rescript
+Float.toExponential(1000.0) // "1e+3"
+Float.toExponential(-1000.0) // "-1e+3"
+Float.toExponential(77.0, ~digits=2) // "7.70e+1"
+Float.toExponential(5678.0, ~digits=2) // "5.68e+3"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` less than 0 or greater than 10.
+*/
+@send
+external toExponential: (float, ~digits: int=?) => string = "toExponential"
+
+/**
+`toExponential(v, ~digits)` return a `string` representing the given value in
+exponential notation. `digits` specifies how many digits should appear after
+the decimal point.
+See [`Number.toExponential`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toExponential) on MDN.
+
+## Examples
+
+```rescript
+Float.toExponentialWithPrecision(77.0, ~digits=2) // "7.70e+1"
+Float.toExponentialWithPrecision(5678.0, ~digits=2) // "5.68e+3"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` less than 0 or greater than 10.
+*/
+@deprecated("Use `toExponential` instead")
+@send
+external toExponentialWithPrecision: (float, ~digits: int) => string = "toExponential"
+
+/**
+`toFixed(v, ~digits=?)` return a `string` representing the given
+value using fixed-point notation. `digits` specifies how many digits should
+appear after the decimal point.
+See [`Number.toFixed`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toFixed) on MDN.
+
+## Examples
+
+```rescript
+Float.toFixed(123456.0) // "123456.00"
+Float.toFixed(10.0) // "10.00"
+Float.toFixed(300.0, ~digits=4) // "300.0000"
+Float.toFixed(300.0, ~digits=1) // "300.0"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` is less than 0 or larger than 100.
+*/
+@send
+external toFixed: (float, ~digits: int=?) => string = "toFixed"
+
+/**
+`toFixedWithPrecision(v, ~digits)` return a `string` representing the given
+value using fixed-point notation. `digits` specifies how many digits should
+appear after the decimal point.
+See [`Number.toFixed`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toFixed) on MDN.
+
+## Examples
+
+```rescript
+Float.toFixedWithPrecision(300.0, ~digits=4) // "300.0000"
+Float.toFixedWithPrecision(300.0, ~digits=1) // "300.0"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` is less than 0 or larger than 100.
+*/
+@deprecated("Use `toFixed` instead")
+@send
+external toFixedWithPrecision: (float, ~digits: int) => string = "toFixed"
+
+/**
+`toPrecision(v, ~digits=?)` return a `string` representing the giver value with
+precision. `digits` specifies the number of significant digits.
+See [`Number.toPrecision`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toPrecision) on MDN.
+
+## Examples
+
+```rescript
+Float.toPrecision(100.0) // "100"
+Float.toPrecision(1.0) // "1"
+Float.toPrecision(100.0, ~digits=2) // "1.0e+2"
+Float.toPrecision(1.0, ~digits=1) // "1"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` is not between 1 and 100 (inclusive).
+Implementations are allowed to support larger and smaller values as well.
+ECMA-262 only requires a precision of up to 21 significant digits.
+*/
+@send
+external toPrecision: (float, ~digits: int=?) => string = "toPrecision"
+
+/**
+`toPrecisionWithPrecision(v, ~digits)` return a `string` representing the giver value with
+precision. `digits` specifies the number of significant digits.
+See [`Number.toPrecision`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toPrecision) on MDN.
+
+## Examples
+
+```rescript
+Float.toPrecisionWithPrecision(100.0, ~digits=2) // "1.0e+2"
+Float.toPrecisionWithPrecision(1.0, ~digits=1) // "1"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` is not between 1 and 100 (inclusive).
+Implementations are allowed to support larger and smaller values as well.
+ECMA-262 only requires a precision of up to 21 significant digits.
+
+*/
+@deprecated("Use `toPrecision` instead")
+@send
+external toPrecisionWithPrecision: (float, ~digits: int) => string = "toPrecision"
+
+/**
+`toString(v)` return a `string` representing the given value.
+See [`Number.toString`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toString) on MDN.
+
+## Examples
+
+```rescript
+Float.toString(1000.0) // "1000"
+Float.toString(-1000.0) // "-1000"
+```
+*/
+@send
+external toString: (float, ~radix: int=?) => string = "toString"
+
+/**
+`toStringWithRadix(v, ~radix)` return a `string` representing the given value.
+`~radix` specifies the radix base to use for the formatted number.
+See [`Number.toString`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toString) on MDN.
+
+## Examples
+
+```rescript
+Float.toStringWithRadix(6.0, ~radix=2) // "110"
+Float.toStringWithRadix(3735928559.0, ~radix=16) // "deadbeef"
+Float.toStringWithRadix(123456.0, ~radix=36) // "2n9c"
+```
+
+## Exceptions
+
+`RangeError`: if `radix` is less than 2 or greater than 36.
+*/
+@deprecated("Use `toString` with `~radix` instead")
+@send
+external toStringWithRadix: (float, ~radix: int) => string = "toString"
+
+/**
+`toLocaleString(v)` return a `string` with language-sensitive representing the
+given value.
+See [`Number.toLocaleString`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toLocaleString) on MDN.
+
+## Examples
+
+```rescript
+// If the application uses English as the default language
+Float.toLocaleString(1000.0) // "1,000"
+
+// If the application uses Portuguese Brazil as the default language
+Float.toLocaleString(1000.0) // "1.000"
+```
+*/
+@send
+external toLocaleString: float => string = "toLocaleString"
+
+/**
+`fromString(str)` return an `option<int>` representing the given value `str`.
+
+## Examples
+
+```rescript
+Float.fromString("0") == Some(0.0)
+Float.fromString("NaN") == None
+Float.fromString("6") == Some(6.0)
+```
+*/
+let fromString: string => option<float>
+
+/**
+`toInt(v)` returns an int to given float `v`.
+
+## Examples
+
+```rescript
+Float.toInt(2.0) == 2
+Float.toInt(1.0) == 1
+Float.toInt(1.1) == 1
+Float.toInt(1.6) == 1
+```
+*/
+external toInt: float => int = "%intoffloat"
+
+/**
+`fromInt(v)` returns a float to given int `v`.
+
+## Examples
+
+```rescript
+Float.fromInt(2) == 2.0
+Float.fromInt(1) == 1.0
+```
+*/
+external fromInt: int => float = "%identity"
+
+/**
+`mod(n1, n2)` calculates the modulo (remainder after division) of two floats.
+
+## Examples
+
+```rescript
+Float.mod(7.0, 4.0) == 3.0
+```
+*/
+external mod: (float, float) => float = "?fmod_float"
+
+/**
+`clamp(~min=?, ~max=?, value)` returns `value`, optionally bounded by `min` and `max`.
+
+if `max` < `min` returns `min`.
+
+## Examples
+
+```rescript
+Float.clamp(4.2) == 4.2
+Float.clamp(4.2, ~min=4.3) == 4.3
+Float.clamp(4.2, ~max=4.1) == 4.1
+Float.clamp(4.2, ~min=4.3, ~max=4.1) == 4.3
+```
+*/
+let clamp: (~min: float=?, ~max: float=?, float) => float
diff --git a/runtime/Float32Array.res b/runtime/Float32Array.res
new file mode 100644
index 0000000000..6c04d070a8
--- /dev/null
+++ b/runtime/Float32Array.res
@@ -0,0 +1,53 @@
+/** The `Float32Array` typed array represents an array of 32-bit floating point numbers in platform byte order. See [Float32Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array)
+*/
+type t = TypedArray.t<float>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "Float32Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `Float32Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array/Float32Array)
+*/
+@new
+external fromArray: array<float> => t = "Float32Array"
+
+/** `fromBuffer` creates a `Float32Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array/Float32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "Float32Array"
+
+/** `fromBufferToEnd` creates a `Float32Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array/Float32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "Float32Array"
+
+/** `fromBufferWithRange` creates a `Float32Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array/Float32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "Float32Array"
+
+/** `fromLength` creates a zero-initialized `Float32Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array/Float32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "Float32Array"
+
+/** `fromArrayLikeOrIterable` creates a `Float32Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "Float32Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `Float32Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => float) => t = "Float32Array.from"
diff --git a/runtime/Float64Array.res b/runtime/Float64Array.res
new file mode 100644
index 0000000000..03203eb189
--- /dev/null
+++ b/runtime/Float64Array.res
@@ -0,0 +1,53 @@
+/** The `Float64Array` typed array represents an array of 64-bit floating point numbers in platform byte order. See [Float64Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array)
+*/
+type t = TypedArray.t<float>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "Float64Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `Float64Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array/Float64Array)
+*/
+@new
+external fromArray: array<float> => t = "Float64Array"
+
+/** `fromBuffer` creates a `Float64Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array/Float64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "Float64Array"
+
+/** `fromBufferToEnd` creates a `Float64Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array/Float64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "Float64Array"
+
+/** `fromBufferWithRange` creates a `Float64Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array/Float64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "Float64Array"
+
+/** `fromLength` creates a zero-initialized `Float64Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array/Float64Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "Float64Array"
+
+/** `fromArrayLikeOrIterable` creates a `Float64Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "Float64Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `Float64Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => float) => t = "Float64Array.from"
diff --git a/runtime/Int.res b/runtime/Int.res
new file mode 100644
index 0000000000..44a7a8a0c2
--- /dev/null
+++ b/runtime/Int.res
@@ -0,0 +1,105 @@
+module Constants = {
+  @inline let minValue = -2147483648
+  @inline let maxValue = 2147483647
+}
+
+external equal: (int, int) => bool = "%equal"
+
+external compare: (int, int) => Ordering.t = "%compare"
+
+@send external toExponential: (int, ~digits: int=?) => string = "toExponential"
+@deprecated("Use `toExponential` instead") @send
+external toExponentialWithPrecision: (int, ~digits: int) => string = "toExponential"
+
+@send external toFixed: (int, ~digits: int=?) => string = "toFixed"
+@deprecated("Use `toFixed` instead") @send
+external toFixedWithPrecision: (int, ~digits: int) => string = "toFixed"
+
+@send external toPrecision: (int, ~digits: int=?) => string = "toPrecision"
+@deprecated("Use `toPrecision` instead") @send
+external toPrecisionWithPrecision: (int, ~digits: int) => string = "toPrecision"
+
+@send external toString: (int, ~radix: int=?) => string = "toString"
+@deprecated("Use `toString` instead") @send
+external toStringWithRadix: (int, ~radix: int) => string = "toString"
+@send external toLocaleString: int => string = "toLocaleString"
+
+external toFloat: int => float = "%identity"
+external fromFloat: float => int = "%intoffloat"
+
+let fromString = (x, ~radix=?) => {
+  let maybeInt = switch radix {
+  | Some(radix) => Float.parseInt(x, ~radix)
+  | None => Float.parseInt(x)
+  }
+
+  if Float.isNaN(maybeInt) {
+    None
+  } else if maybeInt > Constants.maxValue->toFloat || maybeInt < Constants.minValue->toFloat {
+    None
+  } else {
+    let asInt = fromFloat(maybeInt)
+    Some(asInt)
+  }
+}
+
+external mod: (int, int) => int = "%modint"
+
+type rangeOptions = {step?: int, inclusive?: bool}
+
+let abs = x =>
+  if x >= 0 {
+    x
+  } else {
+    -x
+  }
+
+@val external ceil: float => float = "Math.ceil"
+
+let range = (start, end, ~options: rangeOptions={}) => {
+  let isInverted = start > end
+
+  let step = switch options.step {
+  | None => isInverted ? -1 : 1
+  | Some(0) if start !== end => Error.raise(Error.RangeError.make("Incorrect range arguments"))
+  | Some(n) => n
+  }
+
+  let length = if isInverted === (step >= 0) {
+    0 // infinite because step goes in opposite direction of end
+  } else if step == 0 {
+    options.inclusive === Some(true) ? 1 : 0
+  } else {
+    let range = isInverted ? start - end : end - start
+    let range = options.inclusive === Some(true) ? range + 1 : range
+    ceil(Float.fromInt(range) /. Float.fromInt(abs(step)))->Float.toInt
+  }
+
+  Array.fromInitializer(~length, i => start + i * step)
+}
+
+@deprecated("Use `range` instead") @send
+let rangeWithOptions = (start, end, options) => range(start, end, ~options)
+
+let clamp = (~min=?, ~max=?, value): int => {
+  let value = switch max {
+  | Some(max) if max < value => max
+  | _ => value
+  }
+  switch min {
+  | Some(min) if min > value => min
+  | _ => value
+  }
+}
+
+module Bitwise = {
+  external land: (int, int) => int = "%andint"
+  external lor: (int, int) => int = "%orint"
+  external lxor: (int, int) => int = "%xorint"
+
+  external lsl: (int, int) => int = "%lslint"
+  external lsr: (int, int) => int = "%lsrint"
+  external asr: (int, int) => int = "%asrint"
+
+  let lnot = x => lxor(x, -1)
+}
diff --git a/runtime/Int.resi b/runtime/Int.resi
new file mode 100644
index 0000000000..9e6f48f160
--- /dev/null
+++ b/runtime/Int.resi
@@ -0,0 +1,468 @@
+/* Copyright (C) 2015-2016 Bloomberg Finance L.P.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/***
+Functions for interacting with JavaScript Number.
+See: [`Number`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number).
+*/
+
+module Constants: {
+  /**
+  The smallest positive number represented in JavaScript.
+  See [`Number.MIN_VALUE`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MIN_VALUE)
+  on MDN.
+
+  ## Examples
+
+  ```rescript
+  Console.log(Int.Constants.minValue)
+  ```
+  */
+  @inline
+  let minValue: int
+  /**
+  The largest positive number represented in JavaScript.
+  See [`Number.MAX_VALUE`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_VALUE)
+  on MDN.
+
+  ## Examples
+
+  ```rescript
+  Console.log(Int.Constants.maxValue)
+  ```
+  */
+  @inline
+  let maxValue: int
+}
+
+external equal: (int, int) => bool = "%equal"
+
+external compare: (int, int) => Ordering.t = "%compare"
+
+/**
+`toExponential(n, ~digits=?)` return a `string` representing the given value in
+exponential notation. `digits` specifies how many digits should appear after
+the decimal point. See [`Number.toExponential`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toExponential)
+
+## Examples
+
+```rescript
+Int.toExponential(1000) // "1e+3"
+Int.toExponential(-1000) // "-1e+3"
+Int.toExponential(77, ~digits=2) // "7.70e+1"
+Int.toExponential(5678, ~digits=2) // "5.68e+3"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` less than 0 or greater than 10.
+*/
+@send
+external toExponential: (int, ~digits: int=?) => string = "toExponential"
+
+/**
+`toExponential(n, ~digits)` return a `string` representing the given value in
+exponential notation. `digits` specifies how many digits should appear after
+the decimal point. See [`Number.toExponential`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toExponential)
+on MDN.
+
+## Examples
+
+```rescript
+Int.toExponentialWithPrecision(77, ~digits=2) // "7.70e+1"
+Int.toExponentialWithPrecision(5678, ~digits=2) // "5.68e+3"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` less than 0 or greater than 10.
+*/
+@deprecated("Use `toExponential` instead")
+@send
+external toExponentialWithPrecision: (int, ~digits: int) => string = "toExponential"
+
+/**
+`toFixed(n, ~digits=?)` return a `string` representing the given
+value using fixed-point notation. `digits` specifies how many digits should
+appear after the decimal point. See [`Number.toFixed`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toFixed)
+on MDN.
+
+## Examples
+
+```rescript
+Int.toFixed(123456) // "123456.00"
+Int.toFixed(10) // "10.00"
+Int.toFixed(300, ~digits=4) // "300.0000"
+Int.toFixed(300, ~digits=1) // "300.0"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` is less than 0 or larger than 100.
+*/
+@send
+external toFixed: (int, ~digits: int=?) => string = "toFixed"
+
+/**
+`toFixedWithPrecision(n, ~digits)` return a `string` representing the given
+value using fixed-point notation. `digits` specifies how many digits should
+appear after the decimal point. See [`Number.toFixed`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toFixed)
+on MDN.
+
+## Examples
+
+```rescript
+Int.toFixedWithPrecision(300, ~digits=4) // "300.0000"
+Int.toFixedWithPrecision(300, ~digits=1) // "300.0"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` is less than 0 or larger than 100.
+*/
+@deprecated("Use `toFixed` instead")
+@send
+external toFixedWithPrecision: (int, ~digits: int) => string = "toFixed"
+
+/**
+`toPrecision(n, ~digits=?)` return a `string` representing the giver value with
+precision. `digits` specifies the number of significant digits. See [`Number.toPrecision`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toPrecision) on MDN.
+
+## Examples
+
+```rescript
+Int.toPrecision(100) // "100"
+Int.toPrecision(1) // "1"
+Int.toPrecision(100, ~digits=2) // "1.0e+2"
+Int.toPrecision(1, ~digits=2) // "1.0"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` is not between 1 and 100 (inclusive).
+Implementations are allowed to support larger and smaller values as well.
+ECMA-262 only requires a precision of up to 21 significant digits.
+*/
+@send
+external toPrecision: (int, ~digits: int=?) => string = "toPrecision"
+
+/**
+`toPrecisionWithPrecision(n, ~digits)` return a `string` representing the giver value with
+precision. `digits` specifies the number of significant digits. See [`Number.toPrecision`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toPrecision) on MDN.
+
+## Examples
+
+```rescript
+Int.toPrecisionWithPrecision(100, ~digits=2) // "1.0e+2"
+Int.toPrecisionWithPrecision(1, ~digits=2) // "1.0"
+```
+
+## Exceptions
+
+- `RangeError`: If `digits` is not between 1 and 100 (inclusive).
+Implementations are allowed to support larger and smaller values as well.
+ECMA-262 only requires a precision of up to 21 significant digits.
+
+*/
+@send
+@deprecated("Use `toPrecision` instead")
+external toPrecisionWithPrecision: (int, ~digits: int) => string = "toPrecision"
+
+/**
+`toString(n, ~radix=?)` return a `string` representing the given value.
+`~radix` specifies the radix base to use for the formatted number.
+See [`Number.toString`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toString)
+on MDN.
+
+## Examples
+
+```rescript
+Int.toString(1000) // "1000"
+Int.toString(-1000) // "-1000"
+Int.toString(6, ~radix=2) // "110"
+Int.toString(373592855, ~radix=16) // "16449317"
+Int.toString(123456, ~radix=36) // "2n9c"
+```
+
+## Exceptions
+
+`RangeError`: if `radix` is less than 2 or greater than 36.
+*/
+@send
+external toString: (int, ~radix: int=?) => string = "toString"
+
+/**
+`toStringWithRadix(n, ~radix)` return a `string` representing the given value.
+`~radix` specifies the radix base to use for the formatted number.
+See [`Number.toString`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toString)
+on MDN.
+
+## Examples
+
+```rescript
+Int.toStringWithRadix(6, ~radix=2) // "110"
+Int.toStringWithRadix(373592855, ~radix=16) // "16449317"
+Int.toStringWithRadix(123456, ~radix=36) // "2n9c"
+```
+
+## Exceptions
+
+`RangeError`: if `radix` is less than 2 or greater than 36.
+*/
+@deprecated("Use `toString` instead")
+@send
+external toStringWithRadix: (int, ~radix: int) => string = "toString"
+
+/**
+`toLocaleString(n)` return a `string` with language-sensitive representing the
+given value. See [`Number.toLocaleString`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toLocaleString) on MDN.
+
+## Examples
+
+```rescript
+// If the application uses English as the default language
+Int.toLocaleString(1000) // "1,000"
+
+// If the application uses Portuguese Brazil as the default language
+Int.toLocaleString(1000) // "1.000"
+```
+*/
+@send
+external toLocaleString: int => string = "toLocaleString"
+
+/**
+`toFloat(n)` return a `float` representing the given value.
+
+## Examples
+
+```rescript
+Int.toFloat(100) == 100.0
+Int.toFloat(2) == 2.0
+```
+*/
+external toFloat: int => float = "%identity"
+
+/**
+`fromFloat(n)` return an `int` representing the given value. The conversion is
+done by truncating the decimal part.
+
+## Examples
+
+```rescript
+Int.fromFloat(2.0) == 2
+Int.fromFloat(1.999) == 1
+Int.fromFloat(1.5) == 1
+Int.fromFloat(0.9999) == 0
+```
+*/
+external fromFloat: float => int = "%intoffloat"
+
+/**
+`fromString(str, ~radix=?)` return an `option<int>` representing the given value
+`str`. `~radix` specifies the radix base to use for the formatted number.
+
+## Examples
+
+```rescript
+Int.fromString("0") == Some(0)
+Int.fromString("NaN") == None
+Int.fromString("6", ~radix=2) == None
+```
+*/
+let fromString: (string, ~radix: int=?) => option<int>
+
+/**
+`mod(n1, n2)` calculates the modulo (remainder after division) of two integers.
+
+## Examples
+
+```rescript
+Int.mod(7, 4) == 3
+```
+*/
+external mod: (int, int) => int = "%modint"
+
+/**
+The options for `range`.
+*/
+type rangeOptions = {step?: int, inclusive?: bool}
+
+/**
+`range(start, end, ~options=?)` returns an int array of the sequence of integers in the
+range `[start, end)`. That is, including `start` but excluding `end`.
+
+If `step` is not set and `start < end`, the sequence will be increasing in steps of 1.
+
+If `step` is not set and `start > end`, the sequence will be decreasing in steps of -1.
+
+If `step` is set, the sequence will increase or decrease by that amount for each
+step. If `start < end` and `step` is negative, or vice versa, an empty array is
+returned since the sequence would otherwise never reach or exceed the end value
+and hence be infinite. If `step` is `0` and `start !=` end, a `RangeError` is
+raised as the sequence would never reach or exceed the end value and hence be
+infinite.
+
+If `inclusive` is set to `true`, the sequence will include `end` if `step` is
+set such that the sequence includes it.
+
+## Examples
+
+```rescript
+Int.range(3, 6) == [3, 4, 5]
+Int.range(-3, -1) == [-3, -2]
+Int.range(3, 1) == [3, 2]
+Int.range(3, 7, ~options={step: 2}) == [3, 5]
+Int.range(3, 7, ~options={step: 2, inclusive: true}) == [3, 5, 7]
+Int.range(3, 6, ~options={step: -2}) // RangeError
+```
+
+## Exceptions
+
+- Raises `RangeError` if `step == 0 && start != end`.
+*/
+let range: (int, int, ~options: rangeOptions=?) => array<int>
+
+/**
+`rangeWithOptions(start, end, options)` is like `range`, but with `step` and
+`inclusive` options configurable.
+
+If `step` is set, the sequence will increase or decrease by that amount for each
+step. If `start < end` and `step` is negative, or vice versa, an empty array is
+returned since the sequence would otherwise never reach or exceed the end value
+and hence be infinite. If `step` is `0` and `start !=` end, a `RangeError` is
+raised as the sequence would never reach or exceed the end value and hence be
+infinite.
+
+If `inclusive` is set to `true`, the sequence will include `end` if `step` is
+set such that the sequence includes it.
+
+## Examples
+
+```rescript
+Int.rangeWithOptions(3, 7, {step: 2}) == [3, 5]
+Int.rangeWithOptions(3, 7, {step: 2, inclusive: true}) == [3, 5, 7]
+Int.rangeWithOptions(3, 6, {step: -2}) // RangeError
+```
+
+## Exceptions
+
+- Raises `RangeError` if `step == 0 && start != end`.
+*/
+@deprecated("Use `range` instead")
+let rangeWithOptions: (int, int, rangeOptions) => array<int>
+
+/**
+`clamp(~min=?, ~max=?, value)` returns `value`, optionally bounded by `min` and `max`.
+
+if `max` < `min` returns `min`.
+
+## Examples
+
+```rescript
+Int.clamp(42) == 42
+Int.clamp(42, ~min=50) == 50
+Int.clamp(42, ~max=40) == 40
+Int.clamp(42, ~min=50, ~max=40) == 50
+```
+*/
+let clamp: (~min: int=?, ~max: int=?, int) => int
+
+module Bitwise: {
+  /**
+  `land(n1, n2)` calculates the bitwise logical AND of two integers.
+
+  ## Examples
+
+  ```rescript
+  Int.Bitwise.land(7, 4) == 4
+  ```
+  */
+  external land: (int, int) => int = "%andint"
+
+  /**
+  `lor(n1, n2)` calculates the bitwise logical OR of two integers.
+
+  ## Examples
+
+  ```rescript
+  Int.Bitwise.lor(7, 4) == 7
+  ```
+  */
+  external lor: (int, int) => int = "%orint"
+
+  /**
+  `lxor(n1, n2)` calculates the bitwise logical XOR of two integers.
+
+  ## Examples
+
+  ```rescript
+  Int.Bitwise.lxor(7, 4) == 3
+  ```
+  */
+  external lxor: (int, int) => int = "%xorint"
+
+  /**
+  `lnot(n)` calculates the bitwise logical NOT of an integer.
+
+  ## Examples
+
+  ```rescript
+  Int.Bitwise.lnot(2) == -3
+  ```
+  */
+  let lnot: int => int
+
+  /**
+  `lsl(n, length)` calculates the bitwise logical left shift of an integer `n` by `length`.
+
+  ## Examples
+
+  ```rescript
+  Int.Bitwise.lsl(4, 1) == 8
+  ```
+  */
+  external lsl: (int, int) => int = "%lslint"
+
+  /**
+  `lsr(n, length)` calculates the bitwise logical right shift of an integer `n` by `length`.
+
+  ## Examples
+
+  ```rescript
+  Int.Bitwise.lsr(8, 1) == 4
+  ```
+  */
+  external lsr: (int, int) => int = "%lsrint"
+
+  /**
+  `asr(n, length)` calculates the bitwise arithmetic right shift of an integer `n` by `length`.
+
+  ## Examples
+
+  ```rescript
+  Int.Bitwise.asr(4, 1) == 2
+  ```
+  */
+  external asr: (int, int) => int = "%asrint"
+}
diff --git a/runtime/Int16Array.res b/runtime/Int16Array.res
new file mode 100644
index 0000000000..8fe25cf2ae
--- /dev/null
+++ b/runtime/Int16Array.res
@@ -0,0 +1,53 @@
+/** The `Int16Array` typed array represents an array of twos-complement 16-bit signed integers in platform byte order. See [Int16Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int16Array)
+*/
+type t = TypedArray.t<int>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "Int16Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `Int16Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int16Array/Int16Array)
+*/
+@new
+external fromArray: array<int> => t = "Int16Array"
+
+/** `fromBuffer` creates a `Int16Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int16Array/Int16Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "Int16Array"
+
+/** `fromBufferToEnd` creates a `Int16Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int16Array/Int16Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "Int16Array"
+
+/** `fromBufferWithRange` creates a `Int16Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int16Array/Int16Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "Int16Array"
+
+/** `fromLength` creates a zero-initialized `Int16Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int16Array/Int16Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "Int16Array"
+
+/** `fromArrayLikeOrIterable` creates a `Int16Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "Int16Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `Int16Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => int) => t = "Int16Array.from"
diff --git a/runtime/Int32Array.res b/runtime/Int32Array.res
new file mode 100644
index 0000000000..febba5a2c7
--- /dev/null
+++ b/runtime/Int32Array.res
@@ -0,0 +1,53 @@
+/** The `Int32Array` typed array represents an array of twos-complemenet 32-bit signed integers in platform byte order. See [Int32Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array)
+*/
+type t = TypedArray.t<int>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "Int32Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `Int32Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array/Int32Array)
+*/
+@new
+external fromArray: array<int> => t = "Int32Array"
+
+/** `fromBuffer` creates a `Int32Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array/Int32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "Int32Array"
+
+/** `fromBufferToEnd` creates a `Int32Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array/Int32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "Int32Array"
+
+/** `fromBufferWithRange` creates a `Int32Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array/Int32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "Int32Array"
+
+/** `fromLength` creates a zero-initialized `Int32Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array/Int32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "Int32Array"
+
+/** `fromArrayLikeOrIterable` creates a `Int32Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "Int32Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `Int32Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => int) => t = "Int32Array.from"
diff --git a/runtime/Int8Array.res b/runtime/Int8Array.res
new file mode 100644
index 0000000000..3c8e14ba8b
--- /dev/null
+++ b/runtime/Int8Array.res
@@ -0,0 +1,53 @@
+/** The `Int8Array` typed array represents an array of twos-complement 8-bit signed integers. See [Int8Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array)
+*/
+type t = TypedArray.t<int>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "Int8Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `Int8Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array/Int8Array)
+*/
+@new
+external fromArray: array<int> => t = "Int8Array"
+
+/** `fromBuffer` creates a `Int8Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array/Int8Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "Int8Array"
+
+/** `fromBufferToEnd` creates a `Int8Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array/Int8Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "Int8Array"
+
+/** `fromBufferWithRange` creates a `Int8Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array/Int8Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "Int8Array"
+
+/** `fromLength` creates a zero-initialized `Int8Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array/Int8Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "Int8Array"
+
+/** `fromArrayLikeOrIterable` creates a `Int8Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "Int8Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `Int8Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => int) => t = "Int8Array.from"
diff --git a/runtime/Intl.res b/runtime/Intl.res
new file mode 100644
index 0000000000..da9e86c920
--- /dev/null
+++ b/runtime/Intl.res
@@ -0,0 +1,25 @@
+module Common = Intl_Common
+module Collator = Intl_Collator
+module DateTimeFormat = Intl_DateTimeFormat
+module ListFormat = Intl_ListFormat
+module Locale = Intl_Locale
+module NumberFormat = Intl_NumberFormat
+module PluralRules = Intl_PluralRules
+module RelativeTimeFormat = Intl_RelativeTimeFormat
+module Segmenter = Intl_Segmenter
+module Segments = Intl_Segments
+
+/**
+@throws RangeError
+*/
+external getCanonicalLocalesExn: string => array<string> = "Intl.getCanonicalLocales"
+
+/**
+@throws RangeError
+*/
+external getCanonicalLocalesManyExn: array<string> => array<string> = "Intl.getCanonicalLocales"
+
+/**
+@throws RangeError
+*/
+external supportedValuesOfExn: string => array<string> = "Intl.supportedValuesOf"
diff --git a/runtime/Intl_Collator.res b/runtime/Intl_Collator.res
new file mode 100644
index 0000000000..352f6252b4
--- /dev/null
+++ b/runtime/Intl_Collator.res
@@ -0,0 +1,36 @@
+type t
+
+type usage = [#sort | #search]
+type sensitivity = [#base | #accent | #case | #variant]
+type caseFirst = [#upper | #lower | #"false"]
+
+type options = {
+  localeMatcher?: Intl_Common.localeMatcher,
+  usage?: usage,
+  sensitivity?: sensitivity,
+  ignorePunctuation?: bool,
+  numeric?: bool,
+  caseFirst?: caseFirst,
+}
+
+type resolvedOptions = {
+  locale: string,
+  usage: usage,
+  sensitivity: sensitivity,
+  ignorePunctuation: bool,
+  collation: [Intl_Common.collation | #default],
+  numeric?: bool,
+  caseFirst?: caseFirst,
+}
+
+type supportedLocalesOptions = {localeMatcher: Intl_Common.localeMatcher}
+
+@new external make: (~locales: array<string>=?, ~options: options=?) => t = "Intl.Collator"
+
+@val
+external supportedLocalesOf: (array<string>, ~options: supportedLocalesOptions=?) => t =
+  "Intl.Collator.supportedLocalesOf"
+
+@send external resolvedOptions: t => resolvedOptions = "resolvedOptions"
+
+@send external compare: (t, string, string) => int = "compare"
diff --git a/runtime/Intl_Common.res b/runtime/Intl_Common.res
new file mode 100644
index 0000000000..6cc3a6258c
--- /dev/null
+++ b/runtime/Intl_Common.res
@@ -0,0 +1,156 @@
+type localeMatcher = [#lookup | #"best fit"]
+
+type calendar = [
+  | #buddhist
+  | #chinese
+  | #coptic
+  | #dangi
+  | #ethioaa
+  | #ethiopic
+  | #gregory
+  | #hebrew
+  | #indian
+  | #islamic
+  | #"islamic-umalqura"
+  | #"islamic-tbla"
+  | #"islamic-civil"
+  | #"islamic-rgsa"
+  | #iso8601
+  | #japanese
+  | #persian
+  | #roc
+]
+
+type collation = [
+  | #compat // (Arabic)
+  | #dict // (Sinhala)
+  | #emoji // (root)
+  | #eor // (root)
+  | #phonebk // (German)
+  | #phonetic // (Lingala)
+  | #pinyin // (Chinese)
+  | #stroke // (Chinese)
+  | #trad
+  | #unihan // (Chinese, Japanese, and Korean; not available in Chrome or Edge)
+  | #zhuyin
+] // (Chinese)
+
+type numberingSystem = [
+  | #adlm
+  | #ahom
+  | #arab
+  | #arabext
+  | #bali
+  | #beng
+  | #bhks
+  | #brah
+  | #cakm
+  | #cham
+  | #deva
+  | #diak
+  | #fullwide
+  | #gong
+  | #gonm
+  | #gujr
+  | #guru
+  | #hanidec
+  | #hmng
+  | #hmnp
+  | #java
+  | #kali
+  | #kawi
+  | #khmr
+  | #knda
+  | #lana
+  | #lanatham
+  | #laoo
+  | #latn
+  | #lepc
+  | #limb
+  | #mathbold
+  | #mathdbl
+  | #mathmono
+  | #mathsanb
+  | #mathsans
+  | #mlym
+  | #modi
+  | #mong
+  | #mroo
+  | #mtei
+  | #mymr
+  | #mymrshan
+  | #mymrtlng
+  | #nagm
+  | #newa
+  | #nkoo
+  | #olck
+  | #orya
+  | #osma
+  | #rohg
+  | #saur
+  | #segment
+  | #shrd
+  | #sind
+  | #sinh
+  | #sora
+  | #sund
+  | #takr
+  | #talu
+  | #tamldec
+  | #telu
+  | #thai
+  | #tibt
+  | #tirh
+  | #tnsa
+  | #vaii
+  | #wara
+  | #wcho
+]
+
+type oneTo21 = [
+  | #1
+  | #2
+  | #3
+  | #4
+  | #5
+  | #6
+  | #7
+  | #8
+  | #9
+  | #10
+  | #11
+  | #12
+  | #13
+  | #14
+  | #15
+  | #16
+  | #17
+  | #18
+  | #19
+  | #20
+  | #21
+]
+
+type zeroTo20 = [
+  | #0
+  | #1
+  | #2
+  | #3
+  | #4
+  | #5
+  | #6
+  | #7
+  | #8
+  | #9
+  | #10
+  | #11
+  | #12
+  | #13
+  | #14
+  | #15
+  | #16
+  | #17
+  | #18
+  | #19
+  | #20
+]
diff --git a/runtime/Intl_DateTimeFormat.res b/runtime/Intl_DateTimeFormat.res
new file mode 100644
index 0000000000..12738b5e0d
--- /dev/null
+++ b/runtime/Intl_DateTimeFormat.res
@@ -0,0 +1,125 @@
+type t
+
+type dateStyle = [#full | #long | #medium | #short]
+type timeStyle = [#full | #long | #medium | #short]
+type dayPeriod = [#narrow | #short | #long]
+type weekday = [#narrow | #short | #long]
+type era = [#narrow | #short | #long]
+type year = [#numeric | #"2-digit"]
+type month = [#numeric | #"2-digit" | #narrow | #short | #long]
+type day = [#numeric | #"2-digit"]
+type hour = [#numeric | #"2-digit"]
+type minute = [#numeric | #"2-digit"]
+type second = [#numeric | #"2-digit"]
+
+/**
+Firefox also supports IANA time zone names here
+Node v19+ supports "shortOffset", "shortGeneric", "longOffset", and "longGeneric".
+*/
+type timeZoneName = [
+  | #short
+  | #long
+  | #shortOffset
+  | #shortGeneric
+  | #longOffset
+  | #longGeneric
+]
+
+type hourCycle = [#h11 | #h12 | #h23 | #h24]
+type formatMatcher = [#basic | #"best fit"]
+type fractionalSecondDigits = [#0 | #1 | #2 | #3]
+
+type options = {
+  dateStyle?: dateStyle, // can be used with timeStyle, but not other options
+  timeStyle?: timeStyle, // can be used with dateStyle, but not other options
+  calendar?: Intl_Common.calendar,
+  dayPeriod?: dayPeriod, // only has an effect if a 12-hour clock is used
+  numberingSystem?: Intl_Common.numberingSystem,
+  localeMatcher?: Intl_Common.localeMatcher,
+  timeZone?: string,
+  hour12?: bool,
+  hourCycle?: hourCycle,
+  formatMatcher?: formatMatcher,
+  // date-time components
+  weekday?: weekday,
+  era?: era,
+  year?: year,
+  month?: month,
+  day?: day,
+  hour?: hour,
+  minute?: minute,
+  second?: second,
+  fractionalSecondDigits?: fractionalSecondDigits,
+  timeZoneName?: timeZoneName,
+}
+
+type resolvedOptions = {
+  dateStyle?: dateStyle,
+  timeStyle?: timeStyle,
+  weekday?: weekday,
+  era?: era,
+  year?: year,
+  month?: month,
+  day?: day,
+  hour?: hour,
+  minute?: minute,
+  second?: second,
+  fractionalSecondDigits?: fractionalSecondDigits,
+  timeZoneName?: timeZoneName,
+  calendar: Intl_Common.calendar,
+  hour12: bool,
+  hourCycle: hourCycle,
+  locale: string,
+  numberingSystem: Intl_Common.numberingSystem,
+  timeZone: string,
+}
+
+type supportedLocalesOptions = {localeMatcher: Intl_Common.localeMatcher}
+
+type dateTimeComponent = [
+  | #day
+  | #dayPeriod
+  | #era
+  | #fractionalSecond
+  | #hour
+  | #literal
+  | #minute
+  | #month
+  | #relatedYear
+  | #second
+  | #timeZone
+  | #weekday
+  | #year
+  | #yearName
+]
+
+type dateTimePart = {
+  \"type": dateTimeComponent,
+  value: string,
+}
+
+type dateTimeRangeSource = [#startRange | #shared | #endRange]
+type dateTimeRangePart = {
+  \"type": dateTimeComponent,
+  value: string,
+  source: dateTimeRangeSource,
+}
+
+@new external make: (~locales: array<string>=?, ~options: options=?) => t = "Intl.DateTimeFormat"
+
+@val
+external supportedLocalesOf: (array<string>, ~options: supportedLocalesOptions=?) => t =
+  "Intl.DateTimeFormat.supportedLocalesOf"
+
+@send external resolvedOptions: t => resolvedOptions = "resolvedOptions"
+
+@send external format: (t, Date.t) => string = "format"
+@send
+external formatToParts: (t, Date.t) => array<dateTimePart> = "formatToParts"
+
+@send
+external formatRange: (t, ~startDate: Date.t, ~endDate: Date.t) => string = "formatRange"
+
+@send
+external formatRangeToParts: (t, ~startDate: Date.t, ~endDate: Date.t) => array<dateTimeRangePart> =
+  "formatRangeToParts"
diff --git a/runtime/Intl_ListFormat.res b/runtime/Intl_ListFormat.res
new file mode 100644
index 0000000000..0de3d99917
--- /dev/null
+++ b/runtime/Intl_ListFormat.res
@@ -0,0 +1,47 @@
+type t
+
+type listType = [
+  | #conjunction
+  | #disjunction
+  | #unit
+]
+type style = [
+  | #long
+  | #short
+  | #narrow
+]
+
+type options = {
+  localeMatcher?: Intl_Common.localeMatcher,
+  \"type"?: listType,
+  style?: style,
+}
+
+type listPartComponentType = [
+  | #element
+  | #literal
+]
+
+type listPart = {
+  \"type": listPartComponentType,
+  value: string,
+}
+
+type resolvedOptions = {
+  locale: string,
+  style: style,
+  \"type": listType,
+}
+
+type supportedLocalesOptions = {localeMatcher: Intl_Common.localeMatcher}
+
+@new external make: (~locales: array<string>=?, ~options: options=?) => t = "Intl.ListFormat"
+
+@val
+external supportedLocalesOf: (array<string>, ~options: supportedLocalesOptions=?) => t =
+  "Intl.ListFormat.supportedLocalesOf"
+
+@send external resolvedOptions: t => resolvedOptions = "resolvedOptions"
+
+@send external format: (t, array<string>) => string = "format"
+@send external formatToParts: (t, array<string>) => array<listPart> = "formatToParts"
diff --git a/runtime/Intl_Locale.res b/runtime/Intl_Locale.res
new file mode 100644
index 0000000000..de82a0aa1c
--- /dev/null
+++ b/runtime/Intl_Locale.res
@@ -0,0 +1,30 @@
+type t
+
+type options = {
+  baseName?: string,
+  calendar?: Intl_Common.calendar,
+  collation?: Intl_Common.collation,
+  hourCycle?: [#h11 | #h12 | #h23 | #h24],
+  caseFirst?: [#upper | #lower | #"false"],
+  numberingSystem?: Intl_Common.numberingSystem,
+  numeric?: bool,
+  language?: string,
+  script?: string,
+  region?: string,
+}
+
+@new external make: (string, ~options: options=?) => t = "Intl.Locale"
+
+@get external baseName: t => string = "baseName"
+@get external calendar: t => option<string> = "calendar"
+@get external caseFirst: t => option<string> = "caseFirst"
+@get external collation: t => option<string> = "collation"
+@get external hourCycle: t => option<string> = "hourCycle"
+@get external language: t => string = "language"
+@get external numberingSystem: t => option<string> = "numberingSystem"
+@get external numeric: t => bool = "numeric"
+@get external region: t => option<string> = "region"
+@get external script: t => option<string> = "script"
+
+@send external maximize: t => t = "maximize"
+@send external minimize: t => t = "minimize"
diff --git a/runtime/Intl_NumberFormat.res b/runtime/Intl_NumberFormat.res
new file mode 100644
index 0000000000..e6262ea706
--- /dev/null
+++ b/runtime/Intl_NumberFormat.res
@@ -0,0 +1,211 @@
+module Grouping = Intl_NumberFormat_Grouping
+
+type t
+
+/**
+An ISO 4217 currency code. e.g. USD, EUR, CNY
+*/
+type currency = string
+type currencyDisplay = [#symbol | #narrowSymbol | #code | #name]
+type currencySign = [#accounting | #standard]
+type notation = [#scientific | #standard | #engineering | #compact]
+
+/**
+Used only when notation is #compact
+*/
+type compactDisplay = [#short | #long]
+
+type signDisplay = [
+  | #auto
+  | #always
+  | #exceptZero
+  | #never
+  | #negative
+]
+
+type style = [#decimal | #currency | #percent | #unit]
+
+/**
+Defined in https://tc39.es/proposal-unified-intl-numberformat/section6/locales-currencies-tz_proposed_out.html#sec-issanctionedsimpleunitidentifier
+Only used when style is #unit
+*/
+type unitSystem = string
+
+/**
+Only used when style is #unit
+*/
+type unitDisplay = [#long | #short | #narrow]
+
+type rounding = [
+  | #ceil
+  | #floor
+  | #expand
+  | #trunc
+  | #halfCeil
+  | #halfFloor
+  | #halfExpand
+  | #halfTrunc
+  | #halfEven
+]
+
+type roundingPriority = [#auto | #morePrecision | #lessPrecision]
+
+type roundingIncrement = [
+  | #1
+  | #2
+  | #5
+  | #10
+  | #20
+  | #25
+  | #50
+  | #100
+  | #200
+  | #250
+  | #500
+  | #1000
+  | #2000
+  | #2500
+  | #5000
+]
+
+type trailingZeroDisplay = [#auto | #stripIfInteger | #lessPrecision]
+
+type options = {
+  compactDisplay?: compactDisplay,
+  numberingSystem?: Intl_Common.numberingSystem,
+  currency?: currency,
+  currencyDisplay?: currencyDisplay,
+  currencySign?: currencySign,
+  localeMatcher?: Intl_Common.localeMatcher,
+  notation?: notation,
+  signDisplay?: signDisplay,
+  style?: style,
+  /**
+  required if style == #unit
+  */
+  unit?: unitSystem,
+  unitDisplay?: unitDisplay,
+  useGrouping?: Grouping.t,
+  roundingMode?: rounding, // not available in firefox v110
+  roundingPriority?: roundingPriority, // not available in firefox v110
+  roundingIncrement?: roundingIncrement, // not available in firefox v110
+  /**
+  Supported everywhere but Firefox as of v110
+  */
+  trailingZeroDisplay?: trailingZeroDisplay,
+  // use either this group
+  minimumIntegerDigits?: Intl_Common.oneTo21,
+  minimumFractionDigits?: Intl_Common.zeroTo20,
+  maximumFractionDigits?: Intl_Common.zeroTo20,
+  // OR these
+  minimumSignificantDigits?: Intl_Common.oneTo21,
+  maximumSignificantDigits?: Intl_Common.oneTo21,
+}
+
+type resolvedOptions = {
+  // only when style == "currency"
+  currency?: currency,
+  currencyDisplay?: currencyDisplay,
+  currencySign?: currencySign,
+  // only when notation == "compact"
+  compactDisplay?: compactDisplay,
+  // only when style == "unit"
+  unit: unitSystem,
+  unitDisplay: unitDisplay,
+  roundingMode?: rounding, // not available in firefox v110
+  roundingPriority?: roundingPriority, // not available in firefox v110
+  roundingIncrement?: roundingIncrement, // not available in firefox v110
+  // either this group
+  minimumIntegerDigits?: Intl_Common.oneTo21,
+  minimumFractionDigits?: Intl_Common.zeroTo20,
+  maximumFractionDigits?: Intl_Common.zeroTo20,
+  // OR these
+  minimumSignificantDigits?: Intl_Common.oneTo21,
+  maximumSignificantDigits?: Intl_Common.oneTo21,
+  // always present
+  locale: string,
+  notation: notation,
+  numberingSystem: Intl_Common.numberingSystem,
+  signDisplay: signDisplay,
+  style: style,
+  useGrouping: Grouping.t,
+}
+
+type supportedLocalesOptions = {localeMatcher: Intl_Common.localeMatcher}
+
+type numberFormatPartType = [
+  | #compact
+  | #currency
+  | #decimal
+  | #exponentInteger
+  | #exponentMinusSign
+  | #exponentSeparator
+  | #fraction
+  | #group
+  | #infinity
+  | #integer
+  | #literal
+  | #minusSign
+  | #nan
+  | #plusSign
+  | #percentSign
+  | #unit
+  | #unknown
+]
+
+type numberFormatPart = {
+  \"type": numberFormatPartType,
+  value: string,
+}
+
+type rangeSource = [#startRange | #endRange | #shared]
+
+type numberFormatRangePart = {
+  \"type": numberFormatPartType,
+  value: string,
+  source: rangeSource,
+}
+
+@new external make: (~locales: array<string>=?, ~options: options=?) => t = "Intl.NumberFormat"
+
+@val
+external supportedLocalesOf: (array<string>, ~options: supportedLocalesOptions=?) => t =
+  "Intl.NumberFormat.supportedLocalesOf"
+
+@send external resolvedOptions: t => resolvedOptions = "resolvedOptions"
+
+@send external format: (t, float) => string = "format"
+@send
+external formatRange: (t, ~start: float, ~end: float) => array<string> = "formatRange"
+@send
+external formatToParts: (t, float) => array<numberFormatPart> = "formatToParts"
+@send
+external formatRangeToParts: (t, ~start: float, ~end: float) => array<numberFormatRangePart> =
+  "formatRange"
+
+@send external formatInt: (t, int) => string = "format"
+
+@send
+external formatIntRange: (t, ~start: int, ~end: int) => array<string> = "formatRange"
+@send
+external formatIntToParts: (t, int) => array<numberFormatPart> = "formatToParts"
+
+@send
+external formatIntRangeToParts: (t, ~start: int, ~end: int) => array<numberFormatRangePart> =
+  "formatRange"
+
+@send external formatBigInt: (t, bigint) => string = "format"
+
+@send
+external formatBigIntRange: (t, ~start: bigint, ~end: bigint) => array<string> = "formatRange"
+@send
+external formatBigIntToParts: (t, bigint) => array<numberFormatPart> = "formatToParts"
+
+@send
+external formatBigIntRangeToParts: (t, ~start: bigint, ~end: bigint) => array<numberFormatPart> =
+  "formatRange"
+
+@send external formatString: (t, string) => string = "format"
+
+@send
+external formatStringToParts: (t, string) => array<numberFormatRangePart> = "formatToParts"
diff --git a/runtime/Intl_NumberFormat_Grouping.res b/runtime/Intl_NumberFormat_Grouping.res
new file mode 100644
index 0000000000..600b06ba1e
--- /dev/null
+++ b/runtime/Intl_NumberFormat_Grouping.res
@@ -0,0 +1,15 @@
+type t
+
+type parsed = [#bool(bool) | #always | #auto | #min2]
+
+external fromBool: bool => t = "%identity"
+external fromString: [#always | #auto | #min2] => t = "%identity"
+
+let parseJsValue = value =>
+  switch Type.Classify.classify(value) {
+  | String("always") => Some(#always)
+  | String("auto") => Some(#auto)
+  | String("min2") => Some(#min2)
+  | Bool(value) => Some(#bool(value))
+  | _ => None
+  }
diff --git a/runtime/Intl_PluralRules.res b/runtime/Intl_PluralRules.res
new file mode 100644
index 0000000000..9da532bf81
--- /dev/null
+++ b/runtime/Intl_PluralRules.res
@@ -0,0 +1,62 @@
+type t
+
+type localeType = [#cardinal | #ordinal]
+
+type options = {
+  localeMatcher?: Intl_Common.localeMatcher,
+  \"type"?: localeType,
+  // use either this group
+  minimumIntegerDigits?: Intl_Common.oneTo21,
+  minimumFractionDigits?: Intl_Common.zeroTo20,
+  maximumFractionDigits?: Intl_Common.zeroTo20,
+  // OR this group
+  minimumSignificantDigits?: Intl_Common.oneTo21,
+  maximumSignificantDigits?: Intl_Common.oneTo21,
+}
+
+type pluralCategories = [
+  | #zero
+  | #one
+  | #two
+  | #few
+  | #many
+  | #other
+]
+
+type resolvedOptions = {
+  locale: string,
+  pluralCategories: array<pluralCategories>,
+  \"type": localeType,
+  // either this group
+  minimumIntegerDigits?: Intl_Common.oneTo21,
+  minimumFractionDigits?: Intl_Common.zeroTo20,
+  maximumFractionDigits?: Intl_Common.zeroTo20,
+  // OR this group
+  minimumSignificantDigits?: Intl_Common.oneTo21,
+  maximumSignificantDigits?: Intl_Common.oneTo21,
+}
+
+type supportedLocalesOptions = {localeMatcher: Intl_Common.localeMatcher}
+
+@new external make: (~locales: array<string>=?, ~options: options=?) => t = "Intl.PluralRules"
+
+@val
+external supportedLocalesOf: (array<string>, ~options: supportedLocalesOptions=?) => t =
+  "Intl.PluralRules.supportedLocalesOf"
+
+@send external resolvedOptions: t => resolvedOptions = "resolvedOptions"
+
+type rule = [#zero | #one | #two | #few | #many | #other]
+
+@send external select: (t, float) => rule = "select"
+@send external selectInt: (t, int) => rule = "select"
+@send external selectBigInt: (t, bigint) => rule = "select"
+
+@send
+external selectRange: (t, ~start: float, ~end: float) => rule = "selectRange"
+
+@send
+external selectRangeInt: (t, ~start: int, ~end: int) => rule = "selectRange"
+
+@send
+external selectRangeBigInt: (t, ~start: bigint, ~end: bigint) => rule = "selectRange"
diff --git a/runtime/Intl_RelativeTimeFormat.res b/runtime/Intl_RelativeTimeFormat.res
new file mode 100644
index 0000000000..1d53db642d
--- /dev/null
+++ b/runtime/Intl_RelativeTimeFormat.res
@@ -0,0 +1,40 @@
+type t
+
+type numeric = [#always | #auto]
+type style = [#long | #short | #narrow]
+type timeUnit = [#year | #quarter | #month | #week | #day | #hour | #minute | #second]
+
+type options = {
+  localeMatcher?: Intl_Common.localeMatcher,
+  numeric?: numeric,
+  style?: style,
+}
+
+type supportedLocalesOptions = {localeMatcher: Intl_Common.localeMatcher}
+
+type resolvedOptions = {
+  locale: string,
+  numeric: numeric,
+  style: style,
+  numberingSystem: string,
+}
+
+type relativeTimePartComponent = [#literal | #integer]
+type relativeTimePart = {
+  \"type": relativeTimePartComponent,
+  value: string,
+  unit?: timeUnit,
+}
+
+@new
+external make: (~locales: array<string>=?, ~options: options=?) => t = "Intl.RelativeTimeFormat"
+
+@val
+external supportedLocalesOf: (array<string>, ~options: supportedLocalesOptions=?) => t =
+  "Intl.RelativeTimeFormat.supportedLocalesOf"
+
+@send external resolvedOptions: t => resolvedOptions = "resolvedOptions"
+
+@send external format: (t, int, timeUnit) => string = "format"
+@send
+external formatToParts: (t, int, timeUnit) => array<relativeTimePart> = "formatToParts"
diff --git a/runtime/Intl_Segmenter.res b/runtime/Intl_Segmenter.res
new file mode 100644
index 0000000000..cd5306b962
--- /dev/null
+++ b/runtime/Intl_Segmenter.res
@@ -0,0 +1,34 @@
+/***
+Not supported in Firefox
+*/
+type t
+
+type granularity = [#grapheme | #word | #sentence]
+
+type options = {
+  localeMatcher?: Intl_Common.localeMatcher,
+  granularity?: granularity,
+}
+
+type pluralCategories = [
+  | #zero
+  | #one
+  | #two
+  | #few
+  | #many
+  | #other
+]
+
+type resolvedOptions = {locale: string, granularity: granularity}
+
+type supportedLocalesOptions = {localeMatcher: Intl_Common.localeMatcher}
+
+@new external make: (~locales: array<string>=?, ~options: options=?) => t = "Intl.Segmenter"
+
+@val
+external supportedLocalesOf: (array<string>, ~options: supportedLocalesOptions=?) => t =
+  "Intl.Segmenter.supportedLocalesOf"
+
+@send external resolvedOptions: t => resolvedOptions = "resolvedOptions"
+
+@send external segment: (t, string) => Intl_Segments.t = "segment"
diff --git a/runtime/Intl_Segments.res b/runtime/Intl_Segments.res
new file mode 100644
index 0000000000..33b06ea177
--- /dev/null
+++ b/runtime/Intl_Segments.res
@@ -0,0 +1,18 @@
+/***
+ A Segments instance is an object that represents the segments of a specific string, subject to the locale and options of its constructing Intl.Segmenter instance.
+https://tc39.es/ecma402/#sec-segments-objects
+*/
+type t
+
+type segmentData = {
+  segment: string,
+  index: int,
+  isWordLike: option<bool>,
+  input: string,
+}
+
+@send
+external containing: t => segmentData = "containing"
+
+@send
+external containingWithIndex: (t, int) => segmentData = "containing"
diff --git a/runtime/Iterator.res b/runtime/Iterator.res
new file mode 100644
index 0000000000..80b6829e12
--- /dev/null
+++ b/runtime/Iterator.res
@@ -0,0 +1,20 @@
+type t<'a>
+
+type value<'a> = {
+  done: bool,
+  value: option<'a>,
+}
+
+@send external next: t<'a> => value<'a> = "next"
+external toArray: t<'a> => array<'a> = "Array.from"
+external toArrayWithMapper: (t<'a>, 'a => 'b) => array<'b> = "Array.from"
+
+let forEach = (iterator, f) => {
+  let iteratorDone = ref(false)
+
+  while !iteratorDone.contents {
+    let {done, value} = iterator->next
+    f(value)
+    iteratorDone := done
+  }
+}
diff --git a/runtime/Iterator.resi b/runtime/Iterator.resi
new file mode 100644
index 0000000000..300d4fca7b
--- /dev/null
+++ b/runtime/Iterator.resi
@@ -0,0 +1,101 @@
+/***
+Bindings to JavaScript iterators.
+
+See [`iterator protocols`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols) on MDN.
+*/
+
+/**
+The type representing an iterator.
+*/
+type t<'a>
+
+/**
+The current value of an iterator.
+*/
+type value<'a> = {
+  /**
+  Whether there are more values to iterate on before the iterator is done.
+  */
+  done: bool,
+  /**
+  The value of this iteration, if any.
+  */
+  value: option<'a>,
+}
+
+/**
+Returns the next value of the iterator, if any.
+
+See [iterator protocols](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols) on MDN.
+
+## Examples
+```rescript
+@val external someIterator: Iterator.t<int> = "someIterator"
+
+// Pulls out the next value of the iterator
+let {Iterator.done, value} = someIterator->Iterator.next
+```
+*/
+@send
+external next: t<'a> => value<'a> = "next"
+
+/**
+Turns an iterator into an array of the remaining values.
+Remember that each invocation of `next` of an iterator consumes a value. `Iterator.toArray` will consume all remaining values of the iterator and return them in an array to you.
+
+See [iterator protocols](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols) on MDN.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+map->Map.set("someKey2", "someValue2")
+
+// `Map.keys` returns all keys of the map as an iterator.
+let mapKeysAsArray = map->Map.keys->Iterator.toArray
+
+Console.log(mapKeysAsArray) // Logs ["someKey", "someKey2"] to the console.
+```
+*/
+external toArray: t<'a> => array<'a> = "Array.from"
+
+/**
+`toArray(iterator)` turns `iterator` into an array of its remaining values, applying the provided mapper function on each item.
+Remember that each invocation of `next` of an iterator consumes a value. `Iterator.toArrayWithMapper` will consume all remaining values of the iterator and return them in an array to you.
+
+See [iterator protocols](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols) on MDN.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+map->Map.set("someKey2", "someValue2")
+
+// `Map.keys` returns all keys of the map as an iterator.
+let mapKeysAsArray = map
+  ->Map.keys
+  ->Iterator.toArrayWithMapper(key => key->String.length)
+
+Console.log(mapKeysAsArray) // Logs [7, 8] to the console.
+```
+*/
+external toArrayWithMapper: (t<'a>, 'a => 'b) => array<'b> = "Array.from"
+
+/**
+`forEach(iterator, fn)` consumes all values in the iterator and runs the callback `fn` for each value.
+
+See [iterator protocols](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols) on MDN.
+
+## Examples
+```rescript
+@val external someIterator: Iterator.t<int> = "someIterator"
+
+someIterator->Iterator.forEach(value =>
+  switch value {
+  | Some(value) if value > 10 => Console.log("More than 10!")
+  | _ => ()
+  }
+)
+```
+*/
+let forEach: (t<'a>, option<'a> => unit) => unit
diff --git a/runtime/JSON.res b/runtime/JSON.res
new file mode 100644
index 0000000000..b9ee231e8c
--- /dev/null
+++ b/runtime/JSON.res
@@ -0,0 +1,94 @@
+@unboxed
+type rec t = Js.Json.t =
+  | Boolean(bool)
+  | @as(null) Null
+  | String(string)
+  | Number(float)
+  | Object(Dict.t<t>)
+  | Array(array<t>)
+
+@unboxed
+type replacer = Keys(array<string>) | Replacer((string, t) => t)
+
+@raises @val external parseExn: (string, ~reviver: (string, t) => t=?) => t = "JSON.parse"
+@deprecated("Use `parseExn` with optional parameter instead") @raises @val
+external parseExnWithReviver: (string, (string, t) => t) => t = "JSON.parse"
+
+@val external stringify: (t, ~replacer: replacer=?, ~space: int=?) => string = "JSON.stringify"
+@deprecated("Use `stringify` with optional parameter instead") @val
+external stringifyWithIndent: (t, @as(json`null`) _, int) => string = "JSON.stringify"
+@deprecated("Use `stringify` with optional parameter instead") @val
+external stringifyWithReplacer: (t, (string, t) => t) => string = "JSON.stringify"
+@deprecated("Use `stringify` with optional parameters instead") @val
+external stringifyWithReplacerAndIndent: (t, (string, t) => t, int) => string = "JSON.stringify"
+@deprecated("Use `stringify` with optional parameter instead") @val
+external stringifyWithFilter: (t, array<string>) => string = "JSON.stringify"
+@deprecated("Use `stringify` with optional parameters instead") @val
+external stringifyWithFilterAndIndent: (t, array<string>, int) => string = "JSON.stringify"
+
+@raises @val
+external stringifyAny: ('a, ~replacer: replacer=?, ~space: int=?) => option<string> =
+  "JSON.stringify"
+@deprecated("Use `stringifyAny` with optional parameter instead") @raises @val
+external stringifyAnyWithIndent: ('a, @as(json`null`) _, int) => option<string> = "JSON.stringify"
+@deprecated("Use `stringifyAny` with optional parameter instead") @raises @val
+external stringifyAnyWithReplacer: ('a, (string, t) => t) => option<string> = "JSON.stringify"
+@deprecated("Use `stringifyAny` with optional parameters instead") @raises @val
+external stringifyAnyWithReplacerAndIndent: ('a, (string, t) => t, int) => option<string> =
+  "JSON.stringify"
+@deprecated("Use `stringifyAny` with optional parameter instead") @raises @val
+external stringifyAnyWithFilter: ('a, array<string>) => string = "JSON.stringify"
+@deprecated("Use `stringifyAny` with optional parameters instead") @raises @val
+external stringifyAnyWithFilterAndIndent: ('a, array<string>, int) => string = "JSON.stringify"
+
+module Classify = {
+  type t =
+    | Bool(bool)
+    | Null
+    | String(string)
+    | Number(float)
+    | Object(Dict.t<t>)
+    | Array(array<t>)
+
+  @val external _internalClass: 'a => string = "Object.prototype.toString.call"
+  external _asBool: 'a => bool = "%identity"
+  external _asString: 'a => string = "%identity"
+  external _asFloat: 'a => float = "%identity"
+  external _asArray: 'a => array<Js.Json.t> = "%identity"
+  external _asDict: 'a => Dict.t<Js.Json.t> = "%identity"
+
+  let classify = value => {
+    switch _internalClass(value) {
+    | "[object Boolean]" => Bool(_asBool(value))
+    | "[object Null]" => Null
+    | "[object String]" => String(_asString(value))
+    | "[object Number]" => Number(_asFloat(value))
+    | "[object Array]" => Array(_asArray(value))
+    | _ => Object(_asDict(value))
+    }
+  }
+}
+
+module Encode = {
+  external bool: bool => t = "%identity"
+  external null: t = "#null"
+  external string: string => t = "%identity"
+  external int: int => t = "%identity"
+  external float: float => t = "%identity"
+  external object: Dict.t<t> => t = "%identity"
+  external array: array<t> => t = "%identity"
+}
+
+module Decode = {
+  let bool = (json: t) => Type.typeof(json) === #boolean ? Some((Obj.magic(json): bool)) : None
+  let null = (json: t) => Obj.magic(json) === Null.null ? Some(Null.null) : None
+  let string = (json: t) => Type.typeof(json) === #string ? Some((Obj.magic(json): string)) : None
+  let float = (json: t) => Type.typeof(json) === #number ? Some((Obj.magic(json): float)) : None
+  let object = (json: t) =>
+    if Type.typeof(json) === #object && !Array.isArray(json) && !(Obj.magic(json) === Null.null) {
+      Some((Obj.magic(json): Dict.t<t>))
+    } else {
+      None
+    }
+  let array = (json: t) => Array.isArray(json) ? Some((Obj.magic(json): array<t>)) : None
+}
diff --git a/runtime/JSON.resi b/runtime/JSON.resi
new file mode 100644
index 0000000000..eeccc56bad
--- /dev/null
+++ b/runtime/JSON.resi
@@ -0,0 +1,762 @@
+/***
+Functions for interacting with JSON.
+*/
+
+/** 
+A type representing a JSON object.
+*/
+@unboxed
+type rec t = Js.Json.t =
+  | Boolean(bool)
+  | @as(null) Null
+  | String(string)
+  | Number(float)
+  | Object(Dict.t<t>)
+  | Array(array<t>)
+
+@unboxed
+type replacer = Keys(array<string>) | Replacer((string, t) => t)
+
+/** 
+`parseExn(string, ~reviver=?)` 
+
+Parses a JSON string or throws a JavaScript exception (SyntaxError), if the string isn't valid.
+The reviver describes how the value should be transformed. It is a function which receives a key and a value.
+It returns a JSON type.
+
+## Examples
+```rescript
+try {
+  let _ = JSON.parseExn(`{"foo":"bar","hello":"world"}`)
+  // { foo: 'bar', hello: 'world' }
+
+  let _ = JSON.parseExn("")
+  // error
+} catch {
+| Exn.Error(_) => Console.log("error")
+}
+
+let reviver = (_, value: JSON.t) =>
+  switch value {
+  | String(string) => string->String.toUpperCase->JSON.Encode.string
+  | Number(number) => (number *. 2.0)->JSON.Encode.float
+  | _ => value
+  }
+
+let jsonString = `{"hello":"world","someNumber":21}`
+
+try {
+  JSON.parseExn(jsonString, ~reviver)->Console.log
+  // { hello: 'WORLD', someNumber: 42 }
+
+  JSON.parseExn("", ~reviver)->Console.log
+  // error
+} catch {
+| Exn.Error(_) => Console.log("error")
+}
+```
+
+## Exceptions 
+
+- Raises a SyntaxError (Exn.t) if the string isn't valid JSON.
+*/
+@raises(Exn.t)
+@val
+external parseExn: (string, ~reviver: (string, t) => t=?) => t = "JSON.parse"
+
+/** 
+`parseExnWithReviver(string, reviver)` 
+
+Parses a JSON string or throws a JavaScript exception (SyntaxError), if the string isn't valid.
+The reviver describes how the value should be transformed. It is a function which receives a key and a value.
+It returns a JSON type.
+
+## Examples
+```rescript
+let reviver = (_, value: JSON.t) =>
+  switch value {
+  | String(string) => string->String.toUpperCase->JSON.Encode.string
+  | Number(number) => (number *. 2.0)->JSON.Encode.float
+  | _ => value
+  }
+
+let jsonString = `{"hello":"world","someNumber":21}`
+
+try {
+  JSON.parseExnWithReviver(jsonString, reviver)->Console.log
+  // { hello: 'WORLD', someNumber: 42 }
+
+  JSON.parseExnWithReviver("", reviver)->Console.log
+  // error
+} catch {
+| Exn.Error(_) => Console.log("error")
+}
+```
+
+## Exceptions 
+
+- Raises a SyntaxError if the string isn't valid JSON.
+*/
+@deprecated("Use `parseExn` with optional parameter instead")
+@raises(Exn.t)
+@val
+external parseExnWithReviver: (string, (string, t) => t) => t = "JSON.parse"
+
+/** 
+`stringify(json, ~replacer=?, ~space=?)` 
+
+Converts a JSON object to a JSON string.
+The replacer describes how the value should be transformed. It is a function which receives a key and a value,
+or an array of keys which should be included in the output.
+If you want to stringify any type, use `JSON.stringifyAny` instead.
+
+## Examples
+```rescript
+let json =
+  Dict.fromArray([
+    ("foo", JSON.Encode.string("bar")),
+    ("hello", JSON.Encode.string("world")),
+    ("someNumber", JSON.Encode.int(42)),
+  ])->JSON.Encode.object
+
+JSON.stringify(json)
+// {"foo":"bar","hello":"world","someNumber":42}
+
+JSON.stringify(json, ~space=2)
+// {
+//   "foo": "bar",
+//   "hello": "world",
+//   "someNumber": 42
+// }
+
+JSON.stringify(json, ~replacer=Keys(["foo", "someNumber"]))
+// {"foo":"bar","someNumber":42}
+
+let replacer = JSON.Replacer((_, value) => {
+  let decodedValue = value->JSON.Decode.string
+
+  switch decodedValue {
+  | Some(string) => string->String.toUpperCase->JSON.Encode.string
+  | None => value
+  }
+})
+
+JSON.stringify(json, ~replacer)
+// {"foo":"BAR","hello":"WORLD","someNumber":42}
+```
+*/
+@val
+external stringify: (t, ~replacer: replacer=?, ~space: int=?) => string = "JSON.stringify"
+
+/** 
+`stringifyWithIndent(json, indentation)` 
+
+Converts a JSON object to a JSON string. The output will be indented.
+If you want to stringify any type, use `JSON.stringifyAnyWithIndent` instead.
+
+## Examples
+```rescript
+let json =
+  Dict.fromArray([
+    ("foo", JSON.Encode.string("bar")),
+    ("hello", JSON.Encode.string("world")),
+    ("someNumber", JSON.Encode.int(42)),
+  ])->JSON.Encode.object
+
+JSON.stringifyWithIndent(json, 2)
+// {
+//   "foo": "bar",
+//   "hello": "world",
+//   "someNumber": 42
+// }
+```
+*/
+@deprecated("Use `stringify` with optional parameter instead")
+@val
+external stringifyWithIndent: (t, @as(json`null`) _, int) => string = "JSON.stringify"
+
+/** 
+`stringifyWithReplacer(json, replacer)` 
+
+Converts a JSON object to a JSON string.
+The replacer describes how the value should be transformed. It is a function which receives a key and a value.
+If you want to stringify any type, use `JSON.stringifyAnyWithReplacer` instead.
+
+## Examples
+```rescript
+let json =
+  Dict.fromArray([
+    ("foo", JSON.Encode.string("bar")),
+    ("hello", JSON.Encode.string("world")),
+    ("someNumber", JSON.Encode.int(42)),
+  ])->JSON.Encode.object
+
+let replacer = (_, value) => {
+  let decodedValue = value->JSON.Decode.string
+
+  switch decodedValue {
+  | Some(string) => string->String.toUpperCase->JSON.Encode.string
+  | None => value
+  }
+}
+
+JSON.stringifyWithReplacer(json, replacer)
+// {"foo":"BAR","hello":"WORLD","someNumber":42}
+```
+*/
+@deprecated("Use `stringify` with optional parameter instead")
+@val
+external stringifyWithReplacer: (t, (string, t) => t) => string = "JSON.stringify"
+
+/** 
+`stringifyWithReplacerAndIndent(json, replacer, indentation)`
+
+Converts a JSON object to a JSON string. The output will be indented.
+The replacer describes how the value should be transformed. It is a function which receives a key and a value.
+If you want to stringify any type, use `JSON.stringifyAnyWithReplacerAndIndent` instead.
+
+## Examples
+```rescript
+let json =
+  Dict.fromArray([
+    ("foo", JSON.Encode.string("bar")),
+    ("hello", JSON.Encode.string("world")),
+    ("someNumber", JSON.Encode.int(42)),
+  ])->JSON.Encode.object
+
+let replacer = (_, value) => {
+  let decodedValue = value->JSON.Decode.string
+
+  switch decodedValue {
+  | Some(string) => string->String.toUpperCase->JSON.Encode.string
+  | None => value
+  }
+}
+
+JSON.stringifyWithReplacerAndIndent(json, replacer, 2)
+// {
+//   "foo": "BAR",
+//   "hello": "WORLD",
+//   "someNumber": 42
+// }
+```
+*/
+@deprecated("Use `stringify` with optional parameters instead")
+@val
+external stringifyWithReplacerAndIndent: (t, (string, t) => t, int) => string = "JSON.stringify"
+
+/** 
+`stringifyWithFilter(json, filter)` 
+
+Converts a JSON object to a JSON string.
+The filter is an array of keys, which should be included in the output.
+If you want to stringify any type, use `JSON.stringifyAnyWithFilter` instead.
+
+## Examples
+```rescript
+let json =
+  Dict.fromArray([
+    ("foo", JSON.Encode.string("bar")),
+    ("hello", JSON.Encode.string("world")),
+    ("someNumber", JSON.Encode.int(42)),
+  ])->JSON.Encode.object
+
+JSON.stringifyWithFilter(json, ["foo", "someNumber"])
+// {"foo":"bar","someNumber":42}
+```
+*/
+@deprecated("Use `stringify` with optional parameter instead")
+@val
+external stringifyWithFilter: (t, array<string>) => string = "JSON.stringify"
+
+/** 
+`stringifyWithFilterAndIndent(json, filter, indentation)` 
+
+Converts a JSON object to a JSON string. The output will be indented.
+The filter is an array of keys, which should be included in the output.
+If you want to stringify any type, use `JSON.stringifyAnyWithFilterAndIndent` instead.
+
+## Examples
+```rescript
+let json =
+  Dict.fromArray([
+    ("foo", JSON.Encode.string("bar")),
+    ("hello", JSON.Encode.string("world")),
+    ("someNumber", JSON.Encode.int(42)),
+  ])->JSON.Encode.object
+
+JSON.stringifyWithFilterAndIndent(json, ["foo", "someNumber"], 2)
+// {
+//   "foo": "bar",
+//   "someNumber": 42
+// }
+```
+*/
+@deprecated("Use `stringify` with optional parameters instead")
+@val
+external stringifyWithFilterAndIndent: (t, array<string>, int) => string = "JSON.stringify"
+
+/** 
+`stringifyAny(any, ~replacer=?, ~space=?)` 
+
+Converts any type to a JSON string.
+The replacer describes how the value should be transformed. It is a function which receives a key and a value.
+Stringifying a function or `undefined` will return `None`.
+If the value contains circular references or `BigInt`s, the function will throw a JavaScript exception (TypeError).
+If you want to stringify a JSON object, use `JSON.stringify` instead.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([
+  ("foo", JSON.Encode.string("bar")),
+  ("hello", JSON.Encode.string("world")),
+  ("someNumber", JSON.Encode.int(42)),
+])
+
+JSON.stringifyAny(dict)
+// {"foo":"bar","hello":"world","someNumber":42}
+
+JSON.stringifyAny(dict, ~space=2)
+// {
+//   "foo": "bar",
+//   "hello": "world",
+//   "someNumber": 42
+// }
+
+JSON.stringifyAny(dict, ~replacer=Keys(["foo", "someNumber"]))
+// {"foo":"bar","someNumber":42}
+
+let replacer = JSON.Replacer((_, value) => {
+  let decodedValue = value->JSON.Decode.string
+
+  switch decodedValue {
+  | Some(string) => string->String.toUpperCase->JSON.Encode.string
+  | None => value
+  }
+})
+
+JSON.stringifyAny(dict, ~replacer)
+// {"foo":"BAR","hello":"WORLD","someNumber":42}
+
+JSON.stringifyAny(() => "hello world")
+// None
+
+BigInt.fromInt(0)->JSON.stringifyAny
+// exception
+```
+
+## Exceptions 
+
+- Raises a TypeError if the value contains circular references.
+- Raises a TypeError if the value contains `BigInt`s.
+*/
+@raises(Exn.t)
+@val
+external stringifyAny: ('a, ~replacer: replacer=?, ~space: int=?) => option<string> =
+  "JSON.stringify"
+
+/** 
+`stringifyAnyWithIndent(any, indentation)` 
+
+Converts any type to a JSON string. The output will be indented.
+Stringifying a function or `undefined` will return `None`.
+If the value contains circular references or `BigInt`s, the function will throw a JavaScript exception (TypeError).
+If you want to stringify a JSON object, use `JSON.stringifyWithIndent` instead.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([
+  ("foo", JSON.Encode.string("bar")),
+  ("hello", JSON.Encode.string("world")),
+  ("someNumber", JSON.Encode.int(42)),
+])
+
+JSON.stringifyAnyWithIndent(dict, 2)
+// {
+//   "foo": "bar",
+//   "hello": "world",
+//   "someNumber": 42
+// }
+
+JSON.stringifyAny(() => "hello world")
+// None
+
+BigInt.fromInt(0)->JSON.stringifyAny
+// exception
+```
+
+## Exceptions 
+
+- Raises a TypeError if the value contains circular references.
+- Raises a TypeError if the value contains `BigInt`s.
+*/
+@deprecated("Use `stringifyAny` with optional parameter instead")
+@raises(Exn.t)
+@val
+external stringifyAnyWithIndent: ('a, @as(json`null`) _, int) => option<string> = "JSON.stringify"
+
+/** 
+`stringifyAnyWithReplacer(json, replacer)`
+
+Converts any type to a JSON string.
+The replacer describes how the value should be transformed. It is a function which receives a key and a value.
+Stringifying a function or `undefined` will return `None`.
+If the value contains circular references or `BigInt`s, the function will throw a JavaScript exception (TypeError).
+If you want to stringify a JSON object, use `JSON.stringifyWithReplacer` instead.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([
+  ("foo", JSON.Encode.string("bar")),
+  ("hello", JSON.Encode.string("world")),
+  ("someNumber", JSON.Encode.int(42)),
+])
+
+let replacer = (_, value) => {
+  let decodedValue = value->JSON.Decode.string
+
+  switch decodedValue {
+  | Some(string) => string->String.toUpperCase->JSON.Encode.string
+  | None => value
+  }
+}
+
+JSON.stringifyAnyWithReplacer(dict, replacer)
+// {"foo":"BAR","hello":"WORLD","someNumber":42}
+
+JSON.stringifyAny(() => "hello world")
+// None
+
+BigInt.fromInt(0)->JSON.stringifyAny
+// exception
+```
+
+## Exceptions 
+
+- Raises a TypeError if the value contains circular references.
+- Raises a TypeError if the value contains `BigInt`s.
+*/
+@deprecated("Use `stringifyAny` with optional parameter instead")
+@raises
+@val
+external stringifyAnyWithReplacer: ('a, (string, t) => t) => option<string> = "JSON.stringify"
+
+/** 
+`stringifyAnyWithReplacerAndIndent(json, replacer, indentation)` 
+
+Converts any type to a JSON string. The output will be indented.
+The replacer describes how the value should be transformed. It is a function which receives a key and a value.
+Stringifying a function or `undefined` will return `None`.
+If the value contains circular references or `BigInt`s, the function will throw a JavaScript exception (TypeError).
+If you want to stringify a JSON object, use `JSON.stringifyWithReplacerAndIndent` instead.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([
+  ("foo", JSON.Encode.string("bar")),
+  ("hello", JSON.Encode.string("world")),
+  ("someNumber", JSON.Encode.int(42)),
+])
+
+let replacer = (_, value) => {
+  let decodedValue = value->JSON.Decode.string
+
+  switch decodedValue {
+  | Some(string) => string->String.toUpperCase->JSON.Encode.string
+  | None => value
+  }
+}
+
+JSON.stringifyAnyWithReplacerAndIndent(dict, replacer, 2)
+// {
+//   "foo": "BAR",
+//   "hello": "WORLD",
+//   "someNumber": 42
+// }
+
+JSON.stringifyAny(() => "hello world")
+// None
+
+BigInt.fromInt(0)->JSON.stringifyAny
+// exception
+```
+
+## Exceptions 
+
+- Raises a TypeError if the value contains circular references.
+- Raises a TypeError if the value contains `BigInt`s.
+*/
+@deprecated("Use `stringifyAny` with optional parameters instead")
+@raises
+@val
+external stringifyAnyWithReplacerAndIndent: ('a, (string, t) => t, int) => option<string> =
+  "JSON.stringify"
+
+/** 
+`stringifyAnyWithFilter(json, filter)` 
+
+Converts any type to a JSON string.
+The filter is an array of keys, which should be included in the output.
+Stringifying a function or `undefined` will return `None`.
+If the value contains circular references or `BigInt`s, the function will throw a JavaScript exception (TypeError).
+If you want to stringify a JSON object, use `JSON.stringifyWithFilter` instead.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([
+  ("foo", JSON.Encode.string("bar")),
+  ("hello", JSON.Encode.string("world")),
+  ("someNumber", JSON.Encode.int(42)),
+])
+
+JSON.stringifyAnyWithFilter(dict, ["foo", "someNumber"])
+// {"foo": "bar","someNumber": 42}
+
+JSON.stringifyAny(() => "hello world")
+// None
+
+BigInt.fromInt(0)->JSON.stringifyAny
+// exception
+```
+
+## Exceptions 
+
+- Raises a TypeError if the value contains circular references.
+- Raises a TypeError if the value contains `BigInt`s.
+*/
+@deprecated("Use `stringifyAny` with optional parameter instead")
+@raises
+@val
+external stringifyAnyWithFilter: ('a, array<string>) => string = "JSON.stringify"
+
+/** 
+`stringifyAnyWithFilterAndIndent(json, filter, indentation)` 
+
+Converts any type to a JSON string. The output will be indented.
+The filter is an array of keys, which should be included in the output.
+Stringifying a function or `undefined` will return `None`.
+If the value contains circular references or `BigInt`s, the function will throw a JavaScript exception (TypeError).
+If you want to stringify a JSON object, use `JSON.stringifyWithFilterAndIndent` instead.
+
+## Examples
+```rescript
+let dict = Dict.fromArray([
+  ("foo", JSON.Encode.string("bar")),
+  ("hello", JSON.Encode.string("world")),
+  ("someNumber", JSON.Encode.int(42)),
+])
+
+JSON.stringifyAnyWithFilterAndIndent(dict, ["foo", "someNumber"], 2)
+// {
+//   "foo": "bar",
+//   "someNumber": 42
+// }
+
+JSON.stringifyAny(() => "hello world")
+// None
+
+BigInt.fromInt(0)->JSON.stringifyAny
+// exception
+```
+
+## Exceptions 
+
+- Raises a TypeError if the value contains circular references.
+- Raises a TypeError if the value contains `BigInt`s.
+*/
+@deprecated("Use `stringifyAny` with optional parameters instead")
+@raises
+@val
+external stringifyAnyWithFilterAndIndent: ('a, array<string>, int) => string = "JSON.stringify"
+
+module Classify: {
+  /**
+  A type representing a JavaScript type.
+  */
+  type t =
+    | Bool(bool)
+    | Null
+    | String(string)
+    | Number(float)
+    | Object(Dict.t<t>)
+    | Array(array<t>)
+
+  /**
+  Returns the JSON type of any value.
+
+  ## Examples
+  ```rescript
+  JSON.Classify.classify("hello world")
+  // String("hello world")
+
+  JSON.Classify.classify(42)
+  // Number(42)
+  ```
+  */
+  let classify: 'a => t
+}
+
+module Encode: {
+  /**
+  Returns a boolean as a JSON object.
+
+  ## Examples
+  ```rescript
+  JSON.Encode.bool(true)
+  ```
+  */
+  external bool: bool => t = "%identity"
+
+  /**
+  Returns null as a JSON object.
+
+  ## Examples
+  ```rescript
+  JSON.Encode.null
+  ```
+  */
+  external null: t = "#null"
+
+  /**
+  Returns a string as a JSON object.
+
+  ## Examples
+  ```rescript
+  JSON.Encode.string("hello world")
+  ```
+  */
+  external string: string => t = "%identity"
+
+  /**
+  Returns an int as a JSON object.
+
+  ## Examples
+  ```rescript
+  JSON.Encode.int(42)
+  ```
+  */
+  external int: int => t = "%identity"
+
+  /**
+  Returns a float as a JSON object.
+
+  ## Examples
+  ```rescript
+  JSON.Encode.float(42.0)
+  ```
+  */
+  external float: float => t = "%identity"
+
+  /**
+  Returns a dict as a JSON object.
+
+  ## Examples
+  ```rescript
+  let dict = Dict.fromArray([
+    ("foo", JSON.Encode.string("bar")),
+    ("hello", JSON.Encode.string("world")),
+  ])
+
+  JSON.Encode.object(dict)
+  ```
+  */
+  external object: Dict.t<t> => t = "%identity"
+
+  /**
+  Returns an array as a JSON object.
+
+  ## Examples
+  ```rescript
+  let array = [JSON.Encode.string("hello world"), JSON.Encode.int(42)]
+
+  JSON.Encode.array(array)
+  ```
+  */
+  external array: array<t> => t = "%identity"
+}
+
+module Decode: {
+  /**
+  Decodes a single JSON value. If the value is a bool, it will return `Some(bool)` - otherwise it will return `None`.
+
+  ## Examples
+  ```rescript
+  JSON.parseExn(`true`)->JSON.Decode.bool
+  // Some(true)
+
+  JSON.parseExn(`"hello world"`)->JSON.Decode.bool
+  // None
+  ```
+  */
+  let bool: t => option<bool>
+
+  /**
+  Decodes a single JSON value. If the value is null, it will return `Some(Null.t)` - otherwise it will return `None`.
+
+  ## Examples
+  ```rescript
+  JSON.parseExn(`null`)->JSON.Decode.null
+  // Some(null)
+
+  JSON.parseExn(`"hello world"`)->JSON.Decode.null
+  // None
+  ```
+  */
+  let null: t => option<Null.t<'a>>
+
+  /**
+  Decodes a single JSON value. If the value is a string, it will return `Some(string)` - otherwise it will return `None`.
+
+  ## Examples
+  ```rescript
+  JSON.parseExn(`"hello world"`)->JSON.Decode.string
+  // Some("hello world")
+
+  JSON.parseExn(`42`)->JSON.Decode.string
+  // None 
+  ```
+  */
+  let string: t => option<string>
+
+  /**
+  Decodes a single JSON value. If the value is a float, it will return `Some(float)` - otherwise it will return `None`.
+
+  ## Examples
+  ```rescript
+  JSON.parseExn(`42.0`)->JSON.Decode.float
+  // Some(42.0)
+
+  JSON.parseExn(`"hello world"`)->JSON.Decode.float
+  // None
+  ```
+  */
+  let float: t => option<float>
+
+  /**
+  Decodes a single JSON value. If the value is an object, it will return `Some(Dict.t)` - otherwise it will return `None`.
+
+  ## Examples
+  ```rescript
+  JSON.parseExn(`{"foo":"bar"}`)->JSON.Decode.object
+  // Some({ foo: 'bar' })
+
+  JSON.parseExn(`"hello world"`)->JSON.Decode.object
+  // None
+  ```
+  */
+  let object: t => option<Dict.t<t>>
+
+  /**
+  Decodes a single JSON value. If the value is an array, it will return `Some(array)` - otherwise it will return `None`.
+
+  ## Examples
+  ```rescript
+  JSON.parseExn(`["foo", "bar"]`)->JSON.Decode.array
+  // Some([ 'foo', 'bar' ])
+
+  JSON.parseExn(`"hello world"`)->JSON.Decode.array
+  // None
+  ```
+  */
+  let array: t => option<array<t>>
+}
diff --git a/runtime/Js.res b/runtime/Js.res
index 72c535cdb6..fbca7efc08 100644
--- a/runtime/Js.res
+++ b/runtime/Js.res
@@ -86,7 +86,7 @@ module Nullable = Js_null_undefined
 module Null_undefined = Js_null_undefined
 
 /** Provide utilities for dealing with Js exceptions */
-module Exn = Js_exn
+module Exn = Exn
 
 /** Provide bindings to JS array*/
 module Array = Js_array
diff --git a/runtime/Js_null.res b/runtime/Js_null.res
index 33f73888f2..1943fc60f4 100644
--- a/runtime/Js_null.res
+++ b/runtime/Js_null.res
@@ -36,7 +36,7 @@ external getUnsafe: t<'a> => 'a = "%identity"
 
 let getExn = f =>
   switch toOption(f) {
-  | None => Js_exn.raiseError("Js.Null.getExn")
+  | None => Exn.raiseError("Js.Null.getExn")
   | Some(x) => x
   }
 
diff --git a/runtime/Js_option.res b/runtime/Js_option.res
index 8cb8074247..fb48406df4 100644
--- a/runtime/Js_option.res
+++ b/runtime/Js_option.res
@@ -86,7 +86,7 @@ If given `None`, it throws a `getExn` exception.
 */
 let getExn = x =>
   switch x {
-  | None => Js_exn.raiseError("getExn")
+  | None => Exn.raiseError("getExn")
   | Some(x) => x
   }
 
diff --git a/runtime/Js_undefined.res b/runtime/Js_undefined.res
index 00924699ee..699004cea6 100644
--- a/runtime/Js_undefined.res
+++ b/runtime/Js_undefined.res
@@ -37,7 +37,7 @@ external getUnsafe: t<'a> => 'a = "%identity"
 
 let getExn = f =>
   switch toOption(f) {
-  | None => Js_exn.raiseError("Js.Undefined.getExn")
+  | None => Exn.raiseError("Js.Undefined.getExn")
   | Some(x) => x
   }
 
diff --git a/runtime/List.res b/runtime/List.res
index 334b2f8937..3edf67117f 100644
--- a/runtime/List.res
+++ b/runtime/List.res
@@ -1,740 +1,865 @@
-// FIXME:
-//   This exists for compatibility reason.
-//   Move this into Pervasives or Core
+/* Copyright (C) 2017 Hongbo Zhang, Authors of ReScript
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/*
+  perf is not everything, there are better memory represenations
+
+  ```
+  type 'a cell = {
+    mutable head : 'a;
+    mutable tail : 'a opt_cell
+  }
+
+  and 'a opt_cell = 'a cell Js.null
+
+  and 'a t = {
+    length : int ;
+    data : 'a opt_cell
+  }
+  ```
+  However,
+  - people use List not because of its perf, but its
+    convenience, in that case, pattern match and compatibility seems
+    more attractive, we could keep a mutable list
+  - The built in types would indicate that
+    its construtor is immutable, a better optimizer would break such code
+
+  ```
+  type 'a t = {
+    head : 'a;
+    mutable tail : 'a t | int
+  }
+  ```
+  In the future, we could come up with a safer version
+  ```
+  type 'a t =
+  | Nil
+  | Cons of { hd : 'a ; mutable tail : 'a t }
+  ```
+*/
 
-// Below is all deprecated and should be removed in v13
+@@config({flags: ["-bs-noassertfalse"]})
 
 type t<'a> = list<'a>
 
-let rec length_aux = (len, param) =>
-  switch param {
-  | list{} => len
-  | list{_, ...l} => length_aux(len + 1, l)
+module A = {
+  @new external makeUninitializedUnsafe: int => array<'a> = "Array"
+  external min: ('a, 'a) => 'a = "%bs_min"
+
+  let reduceReverseU = (a, x, f) => {
+    let r = ref(x)
+    for i in Array.length(a) - 1 downto 0 {
+      r.contents = f(r.contents, Array.getUnsafe(a, i))
+    }
+    r.contents
+  }
+
+  let reduceReverse2U = (a, b, x, f) => {
+    let r = ref(x)
+    let len = min(Array.length(a), Array.length(b))
+    for i in len - 1 downto 0 {
+      r.contents = f(r.contents, Array.getUnsafe(a, i), Array.getUnsafe(b, i))
+    }
+    r.contents
+  }
+}
+
+external mutableCell: ('a, t<'a>) => t<'a> = "#makemutablelist"
+
+/*
+  `mutableCell x []` == `x`
+  but tell the compiler that is a mutable cell, so it wont
+  be mis-inlined in the future
+   dont inline a binding to mutable cell, it is mutable
+*/
+/* INVARIANT: relies on Literals.tl (internal representation) */
+@set external unsafeMutateTail: (t<'a>, t<'a>) => unit = "tl"
+
+/*
+   - the cell is not empty
+*/
+
+let head = x =>
+  switch x {
+  | list{} => None
+  | list{x, ..._} => Some(x)
+  }
+
+let headExn = x =>
+  switch x {
+  | list{} => raise(Not_found)
+  | list{x, ..._} => x
+  }
+
+let tail = x =>
+  switch x {
+  | list{} => None
+  | list{_, ...xs} => Some(xs)
   }
 
-let length = l => length_aux(0, l)
+let tailExn = x =>
+  switch x {
+  | list{} => raise(Not_found)
+  | list{_, ...t} => t
+  }
 
-let cons = (a, l) => list{a, ...l}
+let add = (xs, x) => list{x, ...xs}
 
-let hd = param =>
-  switch param {
-  | list{} => failwith("hd")
-  | list{a, ..._} => a
+/* Assume `n >=0` */
+let rec nthAux = (x, n) =>
+  switch x {
+  | list{h, ...t} =>
+    if n == 0 {
+      Some(h)
+    } else {
+      nthAux(t, n - 1)
+    }
+  | _ => None
   }
 
-let tl = param =>
-  switch param {
-  | list{} => failwith("tl")
-  | list{_, ...l} => l
+let rec nthAuxAssert = (x, n) =>
+  switch x {
+  | list{h, ...t} =>
+    if n == 0 {
+      h
+    } else {
+      nthAuxAssert(t, n - 1)
+    }
+  | _ => raise(Not_found)
   }
 
-let nth = (l, n) =>
+let get = (x, n) =>
   if n < 0 {
-    invalid_arg("List.nth")
+    None
   } else {
-    let rec nth_aux = (l, n) =>
-      switch l {
-      | list{} => failwith("nth")
-      | list{a, ...l} =>
-        if n == 0 {
-          a
-        } else {
-          nth_aux(l, n - 1)
-        }
-      }
-    nth_aux(l, n)
+    nthAux(x, n)
   }
 
-let nth_opt = (l, n) =>
+let getExn = (x, n) =>
   if n < 0 {
-    invalid_arg("List.nth")
+    raise(Not_found)
   } else {
-    let rec nth_aux = (l, n) =>
-      switch l {
-      | list{} => None
-      | list{a, ...l} =>
-        if n == 0 {
-          Some(a)
-        } else {
-          nth_aux(l, n - 1)
-        }
-      }
-    nth_aux(l, n)
+    nthAuxAssert(x, n)
   }
 
-let append = \"@"
+let rec partitionAux = (p, cell, precX, precY) =>
+  switch cell {
+  | list{} => ()
+  | list{h, ...t} =>
+    let next = mutableCell(h, list{})
+    if p(h) {
+      unsafeMutateTail(precX, next)
+      partitionAux(p, t, next, precY)
+    } else {
+      unsafeMutateTail(precY, next)
+      partitionAux(p, t, precX, next)
+    }
+  }
 
-let rec rev_append = (l1, l2) =>
-  switch l1 {
-  | list{} => l2
-  | list{a, ...l} => rev_append(l, list{a, ...l2})
+let rec splitAux = (cell, precX, precY) =>
+  switch cell {
+  | list{} => ()
+  | list{(a, b), ...t} =>
+    let nextA = mutableCell(a, list{})
+    let nextB = mutableCell(b, list{})
+    unsafeMutateTail(precX, nextA)
+    unsafeMutateTail(precY, nextB)
+    splitAux(t, nextA, nextB)
+  }
+
+/* return the tail pointer so it can continue copy other
+   list
+*/
+let rec copyAuxCont = (cellX, prec) =>
+  switch cellX {
+  | list{} => prec
+  | list{h, ...t} =>
+    let next = mutableCell(h, list{})
+    unsafeMutateTail(prec, next)
+    copyAuxCont(t, next)
+  }
+
+let rec copyAuxWitFilter = (f, cellX, prec) =>
+  switch cellX {
+  | list{} => ()
+  | list{h, ...t} =>
+    if f(h) {
+      let next = mutableCell(h, list{})
+      unsafeMutateTail(prec, next)
+      copyAuxWitFilter(f, t, next)
+    } else {
+      copyAuxWitFilter(f, t, prec)
+    }
+  }
+
+let rec copyAuxWithFilterIndex = (f, cellX, prec, i) =>
+  switch cellX {
+  | list{} => ()
+  | list{h, ...t} =>
+    if f(h, i) {
+      let next = mutableCell(h, list{})
+      unsafeMutateTail(prec, next)
+      copyAuxWithFilterIndex(f, t, next, i + 1)
+    } else {
+      copyAuxWithFilterIndex(f, t, prec, i + 1)
+    }
+  }
+
+let rec copyAuxWitFilterMap = (f, cellX, prec) =>
+  switch cellX {
+  | list{} => ()
+  | list{h, ...t} =>
+    switch f(h) {
+    | Some(h) =>
+      let next = mutableCell(h, list{})
+      unsafeMutateTail(prec, next)
+      copyAuxWitFilterMap(f, t, next)
+    | None => copyAuxWitFilterMap(f, t, prec)
+    }
+  }
+
+let rec removeAssocAuxWithMap = (cellX, x, prec, f) =>
+  switch cellX {
+  | list{} => false
+  | list{(a, _) as h, ...t} =>
+    if f(a, x) {
+      unsafeMutateTail(prec, t)
+      true
+    } else {
+      let next = mutableCell(h, list{})
+      unsafeMutateTail(prec, next)
+      removeAssocAuxWithMap(t, x, next, f)
+    }
+  }
+
+let rec setAssocAuxWithMap = (cellX, x, k, prec, eq) =>
+  switch cellX {
+  | list{} => false
+  | list{(a, _) as h, ...t} =>
+    if eq(a, x) {
+      unsafeMutateTail(prec, list{(x, k), ...t})
+      true
+    } else {
+      let next = mutableCell(h, list{})
+      unsafeMutateTail(prec, next)
+      setAssocAuxWithMap(t, x, k, next, eq)
+    }
+  }
+
+let rec copyAuxWithMap = (cellX, prec, f) =>
+  switch cellX {
+  | list{} => ()
+  | list{h, ...t} =>
+    let next = mutableCell(f(h), list{})
+    unsafeMutateTail(prec, next)
+    copyAuxWithMap(t, next, f)
+  }
+
+let rec zipAux = (cellX, cellY, prec) =>
+  switch (cellX, cellY) {
+  | (list{h1, ...t1}, list{h2, ...t2}) =>
+    let next = mutableCell((h1, h2), list{})
+    unsafeMutateTail(prec, next)
+    zipAux(t1, t2, next)
+  | (list{}, _) | (_, list{}) => ()
+  }
+
+let rec copyAuxWithMap2 = (f, cellX, cellY, prec) =>
+  switch (cellX, cellY) {
+  | (list{h1, ...t1}, list{h2, ...t2}) =>
+    let next = mutableCell(f(h1, h2), list{})
+    unsafeMutateTail(prec, next)
+    copyAuxWithMap2(f, t1, t2, next)
+  | (list{}, _) | (_, list{}) => ()
+  }
+
+let rec copyAuxWithMapI = (f, i, cellX, prec) =>
+  switch cellX {
+  | list{h, ...t} =>
+    let next = mutableCell(f(h, i), list{})
+    unsafeMutateTail(prec, next)
+    copyAuxWithMapI(f, i + 1, t, next)
+  | list{} => ()
   }
 
-let rev = l => rev_append(l, list{})
+let rec takeAux = (n, cell, prec) =>
+  if n == 0 {
+    true
+  } else {
+    switch cell {
+    | list{} => false
+    | list{x, ...xs} =>
+      let cell = mutableCell(x, list{})
+      unsafeMutateTail(prec, cell)
+      takeAux(n - 1, xs, cell)
+    }
+  }
 
-let rec init_tailrec_aux = (acc, i, n, f) =>
-  if i >= n {
-    acc
+let rec splitAtAux = (n, cell, prec) =>
+  if n == 0 {
+    Some(cell)
   } else {
-    init_tailrec_aux(list{f(i), ...acc}, i + 1, n, f)
+    switch cell {
+    | list{} => None
+    | list{x, ...xs} =>
+      let cell = mutableCell(x, list{})
+      unsafeMutateTail(prec, cell)
+      splitAtAux(n - 1, xs, cell)
+    }
   }
 
-let rec init_aux = (i, n, f) =>
-  if i >= n {
-    list{}
+/* invarint `n >= 0` */
+let take = (lst, n) =>
+  if n < 0 {
+    None
+  } else if n == 0 {
+    Some(list{})
   } else {
-    let r = f(i)
-    list{r, ...init_aux(i + 1, n, f)}
+    switch lst {
+    | list{} => None
+    | list{x, ...xs} =>
+      let cell = mutableCell(x, list{})
+      let has = takeAux(n - 1, xs, cell)
+      if has {
+        Some(cell)
+      } else {
+        None
+      }
+    }
+  }
+/* invariant `n >= 0 ` */
+let rec dropAux = (l, n) =>
+  if n == 0 {
+    Some(l)
+  } else {
+    switch l {
+    | list{_, ...tl} => dropAux(tl, n - 1)
+    | list{} => None
+    }
   }
 
-let init = (len, f) =>
-  if len < 0 {
-    invalid_arg("List.init")
-  } else if len > 10_000 {
-    rev(init_tailrec_aux(list{}, 0, len, f))
+let drop = (lst, n) =>
+  if n < 0 {
+    None
   } else {
-    init_aux(0, len, f)
+    dropAux(lst, n)
   }
 
-let rec flatten = param =>
-  switch param {
-  | list{} => list{}
-  | list{l, ...r} => \"@"(l, flatten(r))
+let splitAt = (lst, n) =>
+  if n < 0 {
+    None
+  } else if n == 0 {
+    Some(list{}, lst)
+  } else {
+    switch lst {
+    | list{} => None
+    | list{x, ...xs} =>
+      let cell = mutableCell(x, list{})
+      let rest = splitAtAux(n - 1, xs, cell)
+      switch rest {
+      | Some(rest) => Some(cell, rest)
+      | None => None
+      }
+    }
   }
 
-let concat = flatten
+let concat = (xs, ys) =>
+  switch xs {
+  | list{} => ys
+  | list{h, ...t} =>
+    let cell = mutableCell(h, list{})
+    unsafeMutateTail(copyAuxCont(t, cell), ys)
+    cell
+  }
 
-let rec map = (f, param) =>
-  switch param {
+let map = (xs, f) =>
+  switch xs {
   | list{} => list{}
-  | list{a, ...l} =>
-    let r = f(a)
-    list{r, ...map(f, l)}
+  | list{h, ...t} =>
+    let cell = mutableCell(f(h), list{})
+    copyAuxWithMap(t, cell, f)
+    cell
+  }
+
+let zipBy = (l1, l2, f) =>
+  switch (l1, l2) {
+  | (list{a1, ...l1}, list{a2, ...l2}) =>
+    let cell = mutableCell(f(a1, a2), list{})
+    copyAuxWithMap2(f, l1, l2, cell)
+    cell
+  | (list{}, _) | (_, list{}) => list{}
   }
 
-let rec mapi = (i, f, param) =>
-  switch param {
+let mapWithIndex = (xs, f) =>
+  switch xs {
   | list{} => list{}
-  | list{a, ...l} =>
-    let r = f(i, a)
-    list{r, ...mapi(i + 1, f, l)}
+  | list{h, ...t} =>
+    let cell = mutableCell(f(h, 0), list{})
+    copyAuxWithMapI(f, 1, t, cell)
+    cell
   }
 
-let mapi = (f, l) => mapi(0, f, l)
+let fromInitializer = (~length as n, f) =>
+  if n <= 0 {
+    list{}
+  } else {
+    let headX = mutableCell(f(0), list{})
+    let cur = ref(headX)
+    let i = ref(1)
+    while i.contents < n {
+      let v = mutableCell(f(i.contents), list{})
+      unsafeMutateTail(cur.contents, v)
+      cur.contents = v
+      i.contents = i.contents + 1
+    }
 
-let rev_map = (f, l) => {
-  let rec rmap_f = (accu, param) =>
-    switch param {
-    | list{} => accu
-    | list{a, ...l} => rmap_f(list{f(a), ...accu}, l)
+    headX
+  }
+
+let make = (type a, ~length as n, v: a): list<a> =>
+  if n <= 0 {
+    list{}
+  } else {
+    let headX = mutableCell(v, list{})
+    let cur = ref(headX)
+    let i = ref(1)
+    while i.contents < n {
+      let v = mutableCell(v, list{})
+      unsafeMutateTail(cur.contents, v)
+      cur.contents = v
+      i.contents = i.contents + 1
     }
 
-  rmap_f(list{}, l)
+    headX
+  }
+
+let rec lengthAux = (x, acc) =>
+  switch x {
+  | list{} => acc
+  | list{_, ...t} => lengthAux(t, acc + 1)
+  }
+
+let length = xs => lengthAux(xs, 0)
+let size = length
+
+let rec fillAux = (arr, i, x) =>
+  switch x {
+  | list{} => ()
+  | list{h, ...t} =>
+    Array.setUnsafe(arr, i, h)
+    fillAux(arr, i + 1, t)
+  }
+
+let rec fromArrayAux = (a, i, res) =>
+  if i < 0 {
+    res
+  } else {
+    fromArrayAux(a, i - 1, list{Array.getUnsafe(a, i), ...res})
+  }
+
+let fromArray = a => fromArrayAux(a, Array.length(a) - 1, list{})
+
+let toArray = (x: t<_>) => {
+  let len = length(x)
+  let arr = A.makeUninitializedUnsafe(len)
+  fillAux(arr, 0, x)
+  arr
+}
+
+let toShuffled = xs => {
+  let v = toArray(xs)
+  Array.shuffle(v)
+  fromArray(v)
 }
 
-let rec iter = (f, param) =>
-  switch param {
+/* let rec fillAuxMap arr i x f =
+  match x with
+  | [] -> ()
+  | h::t ->
+    A.setUnsafe arr i (f h [@bs]) ;
+    fillAuxMap arr (i + 1) t f */
+
+/* module J = Js_json */
+/* type json = J.t */
+/* let toJson x f = */
+/* let len = length x in */
+/* let arr = Belt_Array.makeUninitializedUnsafe len in */
+/* fillAuxMap arr 0 x f; */
+/* J.array arr */
+
+/* TODO: best practice about raising excpetion
+   1. raise OCaml exception, no stacktrace
+   2. raise JS exception, how to pattern match
+*/
+
+let rec reverseConcat = (l1, l2) =>
+  switch l1 {
+  | list{} => l2
+  | list{a, ...l} => reverseConcat(l, list{a, ...l2})
+  }
+
+let reverse = l => reverseConcat(l, list{})
+
+let rec flatAux = (prec, xs) =>
+  switch xs {
+  | list{} => unsafeMutateTail(prec, list{})
+  | list{h, ...r} => flatAux(copyAuxCont(h, prec), r)
+  }
+
+let rec flat = xs =>
+  switch xs {
+  | list{} => list{}
+  | list{list{}, ...xs} => flat(xs)
+  | list{list{h, ...t}, ...r} =>
+    let cell = mutableCell(h, list{})
+    flatAux(copyAuxCont(t, cell), r)
+    cell
+  }
+
+let concatMany = xs =>
+  switch xs {
+  | [] => list{}
+  | [x] => x
+  | _ =>
+    let len = Array.length(xs)
+    let v = ref(Array.getUnsafe(xs, len - 1))
+    for i in len - 2 downto 0 {
+      v.contents = concat(Array.getUnsafe(xs, i), v.contents)
+    }
+    v.contents
+  }
+
+let rec mapRevAux = (f, accu, xs) =>
+  switch xs {
+  | list{} => accu
+  | list{a, ...l} => mapRevAux(f, list{f(a), ...accu}, l)
+  }
+
+let mapReverse = (l, f) => mapRevAux(f, list{}, l)
+
+let rec forEach = (xs, f) =>
+  switch xs {
   | list{} => ()
   | list{a, ...l} =>
     f(a)
-    iter(f, l)
+    forEach(l, f)
   }
 
-let rec iteri = (i, f, param) =>
-  switch param {
+let rec forEachWithIndexAux = (xs, f, i) =>
+  switch xs {
   | list{} => ()
   | list{a, ...l} =>
-    f(i, a)
-    iteri(i + 1, f, l)
+    f(a, i)
+    forEachWithIndexAux(l, f, i + 1)
   }
 
-let iteri = (f, l) => iteri(0, f, l)
+let forEachWithIndex = (l, f) => forEachWithIndexAux(l, f, 0)
 
-let rec fold_left = (f, accu, l) =>
+let rec reduce = (l, accu, f) =>
   switch l {
   | list{} => accu
-  | list{a, ...l} => fold_left(f, f(accu, a), l)
+  | list{a, ...l} => reduce(l, f(accu, a), f)
   }
 
-let rec fold_right = (f, l, accu) =>
+let rec reduceReverseUnsafe = (l, accu, f) =>
   switch l {
   | list{} => accu
-  | list{a, ...l} => f(a, fold_right(f, l, accu))
+  | list{a, ...l} => f(reduceReverseUnsafe(l, accu, f), a)
   }
 
-let rec map2 = (f, l1, l2) =>
-  switch (l1, l2) {
-  | (list{}, list{}) => list{}
-  | (list{a1, ...l1}, list{a2, ...l2}) =>
-    let r = f(a1, a2)
-    list{r, ...map2(f, l1, l2)}
-  | (_, _) => invalid_arg("List.map2")
+let reduceReverse = (type a b, l: list<a>, acc: b, f) => {
+  let len = length(l)
+  if len < 1000 {
+    reduceReverseUnsafe(l, acc, f)
+  } else {
+    A.reduceReverseU(toArray(l), acc, f)
+  }
+}
+
+let rec reduceWithIndexAux = (l, acc, f, i) =>
+  switch l {
+  | list{} => acc
+  | list{x, ...xs} => reduceWithIndexAux(xs, f(acc, x, i), f, i + 1)
   }
 
-let rev_map2 = (f, l1, l2) => {
-  let rec rmap2_f = (accu, l1, l2) =>
-    switch (l1, l2) {
-    | (list{}, list{}) => accu
-    | (list{a1, ...l1}, list{a2, ...l2}) => rmap2_f(list{f(a1, a2), ...accu}, l1, l2)
-    | (_, _) => invalid_arg("List.rev_map2")
-    }
+let reduceWithIndex = (l, acc, f) => reduceWithIndexAux(l, acc, f, 0)
 
-  rmap2_f(list{}, l1, l2)
-}
+let rec mapRevAux2 = (l1, l2, accu, f) =>
+  switch (l1, l2) {
+  | (list{a1, ...l1}, list{a2, ...l2}) => mapRevAux2(l1, l2, list{f(a1, a2), ...accu}, f)
+  | (_, list{}) | (list{}, _) => accu
+  }
 
-let rec iter2 = (f, l1, l2) =>
+let mapReverse2 = (l1, l2, f) => mapRevAux2(l1, l2, list{}, f)
+
+let rec forEach2 = (l1, l2, f) =>
   switch (l1, l2) {
-  | (list{}, list{}) => ()
   | (list{a1, ...l1}, list{a2, ...l2}) =>
-    f(a1, a2)
-    iter2(f, l1, l2)
-  | (_, _) => invalid_arg("List.iter2")
+    f(a1, a2)->ignore
+    forEach2(l1, l2, f)
+  | (list{}, _) | (_, list{}) => ()
   }
 
-let rec fold_left2 = (f, accu, l1, l2) =>
+let rec reduce2 = (l1, l2, accu, f) =>
   switch (l1, l2) {
-  | (list{}, list{}) => accu
-  | (list{a1, ...l1}, list{a2, ...l2}) => fold_left2(f, f(accu, a1, a2), l1, l2)
-  | (_, _) => invalid_arg("List.fold_left2")
+  | (list{a1, ...l1}, list{a2, ...l2}) => reduce2(l1, l2, f(accu, a1, a2), f)
+  | (list{}, _) | (_, list{}) => accu
   }
 
-let rec fold_right2 = (f, l1, l2, accu) =>
+let rec reduceReverse2Unsafe = (l1, l2, accu, f) =>
   switch (l1, l2) {
   | (list{}, list{}) => accu
-  | (list{a1, ...l1}, list{a2, ...l2}) => f(a1, a2, fold_right2(f, l1, l2, accu))
-  | (_, _) => invalid_arg("List.fold_right2")
+  | (list{a1, ...l1}, list{a2, ...l2}) => f(reduceReverse2Unsafe(l1, l2, accu, f), a1, a2)
+  | (_, list{}) | (list{}, _) => accu
   }
 
-let rec for_all = (p, param) =>
-  switch param {
+let reduceReverse2 = (type a b c, l1: list<a>, l2: list<b>, acc: c, f) => {
+  let len = length(l1)
+  if len < 1000 {
+    reduceReverse2Unsafe(l1, l2, acc, f)
+  } else {
+    A.reduceReverse2U(toArray(l1), toArray(l2), acc, f)
+  }
+}
+
+let rec every = (xs, p) =>
+  switch xs {
   | list{} => true
-  | list{a, ...l} => p(a) && for_all(p, l)
+  | list{a, ...l} => p(a) && every(l, p)
   }
 
-let rec exists = (p, param) =>
-  switch param {
+let rec some = (xs, p) =>
+  switch xs {
   | list{} => false
-  | list{a, ...l} => p(a) || exists(p, l)
+  | list{a, ...l} => p(a) || some(l, p)
   }
 
-let rec for_all2 = (p, l1, l2) =>
+let rec every2 = (l1, l2, p) =>
   switch (l1, l2) {
-  | (list{}, list{}) => true
-  | (list{a1, ...l1}, list{a2, ...l2}) => p(a1, a2) && for_all2(p, l1, l2)
-  | (_, _) => invalid_arg("List.for_all2")
+  | (_, list{}) | (list{}, _) => true
+  | (list{a1, ...l1}, list{a2, ...l2}) => p(a1, a2) && every2(l1, l2, p)
   }
 
-let rec exists2 = (p, l1, l2) =>
+let rec compareLength = (l1, l2) =>
   switch (l1, l2) {
-  | (list{}, list{}) => false
-  | (list{a1, ...l1}, list{a2, ...l2}) => p(a1, a2) || exists2(p, l1, l2)
-  | (_, _) => invalid_arg("List.exists2")
-  }
-
-let rec mem = (x, param) =>
-  switch param {
-  | list{} => false
-  | list{a, ...l} => compare(a, x) == 0 || mem(x, l)
-  }
-
-let rec memq = (x, param) =>
-  switch param {
-  | list{} => false
-  | list{a, ...l} => a === x || memq(x, l)
+  | (list{}, list{}) => Ordering.equal
+  | (_, list{}) => Ordering.greater
+  | (list{}, _) => Ordering.less
+  | (list{_, ...l1s}, list{_, ...l2s}) => compareLength(l1s, l2s)
   }
 
-let rec assoc = (x, param) =>
-  switch param {
-  | list{} => raise(Not_found)
-  | list{(a, b), ...l} =>
-    if compare(a, x) == 0 {
-      b
+let rec compare = (l1, l2, p) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => Ordering.equal
+  | (_, list{}) => Ordering.greater
+  | (list{}, _) => Ordering.less
+  | (list{a1, ...l1}, list{a2, ...l2}) =>
+    let c = p(a1, a2)
+    if c == Ordering.equal {
+      compare(l1, l2, p)
     } else {
-      assoc(x, l)
+      c
     }
   }
 
-let rec assoc_opt = (x, param) =>
-  switch param {
-  | list{} => None
-  | list{(a, b), ...l} =>
-    if compare(a, x) == 0 {
-      Some(b)
+let rec equal = (l1, l2, p) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => true
+  | (_, list{})
+  | (list{}, _) => false
+  | (list{a1, ...l1}, list{a2, ...l2}) =>
+    if p(a1, a2) {
+      equal(l1, l2, p)
     } else {
-      assoc_opt(x, l)
+      false
     }
   }
 
-let rec assq = (x, param) =>
-  switch param {
-  | list{} => raise(Not_found)
-  | list{(a, b), ...l} =>
-    if a === x {
-      b
-    } else {
-      assq(x, l)
-    }
+let rec some2 = (l1, l2, p) =>
+  switch (l1, l2) {
+  | (list{}, _) | (_, list{}) => false
+  | (list{a1, ...l1}, list{a2, ...l2}) => p(a1, a2) || some2(l1, l2, p)
+  }
+
+let rec has = (xs, x, eq) =>
+  switch xs {
+  | list{} => false
+  | list{a, ...l} => eq(a, x) || has(l, x, eq)
   }
 
-let rec assq_opt = (x, param) =>
-  switch param {
+let rec getAssoc = (xs, x, eq) =>
+  switch xs {
   | list{} => None
   | list{(a, b), ...l} =>
-    if a === x {
+    if eq(a, x) {
       Some(b)
     } else {
-      assq_opt(x, l)
+      getAssoc(l, x, eq)
     }
   }
 
-let rec mem_assoc = (x, param) =>
-  switch param {
-  | list{} => false
-  | list{(a, _), ...l} => compare(a, x) == 0 || mem_assoc(x, l)
-  }
-
-let rec mem_assq = (x, param) =>
-  switch param {
+let rec hasAssoc = (xs, x, eq) =>
+  switch xs {
   | list{} => false
-  | list{(a, _), ...l} => a === x || mem_assq(x, l)
+  | list{(a, _), ...l} => eq(a, x) || hasAssoc(l, x, eq)
   }
 
-let rec remove_assoc = (x, param) =>
-  switch param {
+let removeAssoc = (xs, x, eq) =>
+  switch xs {
   | list{} => list{}
   | list{(a, _) as pair, ...l} =>
-    if compare(a, x) == 0 {
+    if eq(a, x) {
       l
     } else {
-      list{pair, ...remove_assoc(x, l)}
+      let cell = mutableCell(pair, list{})
+      let removed = removeAssocAuxWithMap(l, x, cell, eq)
+      if removed {
+        cell
+      } else {
+        xs
+      }
     }
   }
 
-let rec remove_assq = (x, param) =>
-  switch param {
-  | list{} => list{}
+let setAssoc = (xs, x, k, eq) =>
+  switch xs {
+  | list{} => list{(x, k)}
   | list{(a, _) as pair, ...l} =>
-    if a === x {
-      l
+    if eq(a, x) {
+      list{(x, k), ...l}
     } else {
-      list{pair, ...remove_assq(x, l)}
+      let cell = mutableCell(pair, list{})
+      let replaced = setAssocAuxWithMap(l, x, k, cell, eq)
+      if replaced {
+        cell
+      } else {
+        list{(x, k), ...xs}
+      }
     }
   }
 
-let rec find = (p, param) =>
-  switch param {
-  | list{} => raise(Not_found)
-  | list{x, ...l} =>
-    if p(x) {
-      x
-    } else {
-      find(p, l)
-    }
-  }
+let sort = (xs, cmp) => {
+  let arr = toArray(xs)
+  Array.sort(arr, cmp)
+  fromArray(arr)
+}
 
-let rec find_opt = (p, param) =>
-  switch param {
+let rec find = (xs, p) =>
+  switch xs {
   | list{} => None
   | list{x, ...l} =>
     if p(x) {
       Some(x)
     } else {
-      find_opt(p, l)
+      find(l, p)
     }
   }
 
-let find_all = (p, l) => {
-  let rec find = (accu, param) =>
-    switch param {
-    | list{} => rev(accu)
-    | list{x, ...l} =>
-      if p(x) {
-        find(list{x, ...accu}, l)
-      } else {
-        find(accu, l)
-      }
-    }
-  find(list{}, l)
-}
-
-let filter = find_all
-
-let partition = (p, l) => {
-  let rec part = (yes, no, param) =>
-    switch param {
-    | list{} => (rev(yes), rev(no))
-    | list{x, ...l} =>
-      if p(x) {
-        part(list{x, ...yes}, no, l)
-      } else {
-        part(yes, list{x, ...no}, l)
-      }
-    }
-  part(list{}, list{}, l)
-}
-
-let rec split = param =>
-  switch param {
-  | list{} => (list{}, list{})
-  | list{(x, y), ...l} =>
-    let (rx, ry) = split(l)
-    (list{x, ...rx}, list{y, ...ry})
-  }
-
-let rec combine = (l1, l2) =>
-  switch (l1, l2) {
-  | (list{}, list{}) => list{}
-  | (list{a1, ...l1}, list{a2, ...l2}) => list{(a1, a2), ...combine(l1, l2)}
-  | (_, _) => invalid_arg("List.combine")
-  }
-
-/* sorting */
-
-let rec merge = (cmp, l1, l2) =>
-  switch (l1, l2) {
-  | (list{}, l2) => l2
-  | (l1, list{}) => l1
-  | (list{h1, ...t1}, list{h2, ...t2}) =>
-    if cmp(h1, h2) <= 0 {
-      list{h1, ...merge(cmp, t1, l2)}
+let rec filter = (xs, p) =>
+  switch xs {
+  | list{} => list{}
+  | list{h, ...t} =>
+    if p(h) {
+      let cell = mutableCell(h, list{})
+      copyAuxWitFilter(p, t, cell)
+      cell
     } else {
-      list{h2, ...merge(cmp, l1, t2)}
-    }
-  }
-
-let rec chop = (k, l) =>
-  if k == 0 {
-    l
-  } else {
-    switch l {
-    | list{_, ...t} => chop(k - 1, t)
-    | _ => assert(false)
+      filter(t, p)
     }
   }
 
-let stable_sort = (cmp, l) => {
-  let rec rev_merge = (l1, l2, accu) =>
-    switch (l1, l2) {
-    | (list{}, l2) => rev_append(l2, accu)
-    | (l1, list{}) => rev_append(l1, accu)
-    | (list{h1, ...t1}, list{h2, ...t2}) =>
-      if cmp(h1, h2) <= 0 {
-        rev_merge(t1, l2, list{h1, ...accu})
-      } else {
-        rev_merge(l1, t2, list{h2, ...accu})
-      }
-    }
-
-  let rec rev_merge_rev = (l1, l2, accu) =>
-    switch (l1, l2) {
-    | (list{}, l2) => rev_append(l2, accu)
-    | (l1, list{}) => rev_append(l1, accu)
-    | (list{h1, ...t1}, list{h2, ...t2}) =>
-      if cmp(h1, h2) > 0 {
-        rev_merge_rev(t1, l2, list{h1, ...accu})
-      } else {
-        rev_merge_rev(l1, t2, list{h2, ...accu})
-      }
-    }
-
-  let rec sort = (n, l) =>
-    switch (n, l) {
-    | (2, list{x1, x2, ..._}) =>
-      if cmp(x1, x2) <= 0 {
-        list{x1, x2}
-      } else {
-        list{x2, x1}
-      }
-    | (3, list{x1, x2, x3, ..._}) =>
-      if cmp(x1, x2) <= 0 {
-        if cmp(x2, x3) <= 0 {
-          list{x1, x2, x3}
-        } else if cmp(x1, x3) <= 0 {
-          list{x1, x3, x2}
-        } else {
-          list{x3, x1, x2}
-        }
-      } else if cmp(x1, x3) <= 0 {
-        list{x2, x1, x3}
-      } else if cmp(x2, x3) <= 0 {
-        list{x2, x3, x1}
+let filterWithIndex = (xs, p) => {
+  let rec auxFilterWithIndex = (xs, p, i) =>
+    switch xs {
+    | list{} => list{}
+    | list{h, ...t} =>
+      if p(h, i) {
+        let cell = mutableCell(h, list{})
+        copyAuxWithFilterIndex(p, t, cell, i + 1)
+        cell
       } else {
-        list{x3, x2, x1}
+        auxFilterWithIndex(t, p, i + 1)
       }
-    | (n, l) =>
-      let n1 = asr(n, 1)
-      let n2 = n - n1
-      let l2 = chop(n1, l)
-      let s1 = rev_sort(n1, l)
-      let s2 = rev_sort(n2, l2)
-      rev_merge_rev(s1, s2, list{})
     }
-  and rev_sort = (n, l) =>
-    switch (n, l) {
-    | (2, list{x1, x2, ..._}) =>
-      if cmp(x1, x2) > 0 {
-        list{x1, x2}
-      } else {
-        list{x2, x1}
-      }
-    | (3, list{x1, x2, x3, ..._}) =>
-      if cmp(x1, x2) > 0 {
-        if cmp(x2, x3) > 0 {
-          list{x1, x2, x3}
-        } else if cmp(x1, x3) > 0 {
-          list{x1, x3, x2}
-        } else {
-          list{x3, x1, x2}
-        }
-      } else if cmp(x1, x3) > 0 {
-        list{x2, x1, x3}
-      } else if cmp(x2, x3) > 0 {
-        list{x2, x3, x1}
-      } else {
-        list{x3, x2, x1}
-      }
-    | (n, l) =>
-      let n1 = asr(n, 1)
-      let n2 = n - n1
-      let l2 = chop(n1, l)
-      let s1 = sort(n1, l)
-      let s2 = sort(n2, l2)
-      rev_merge(s1, s2, list{})
-    }
-
-  let len = length(l)
-  if len < 2 {
-    l
-  } else {
-    sort(len, l)
-  }
+  auxFilterWithIndex(xs, p, 0)
 }
 
-let sort = stable_sort
-let fast_sort = stable_sort
-
-/* Note: on a list of length between about 100000 (depending on the minor
-  heap size and the type of the list) and Sys.max_array_size, it is
-  actually faster to use the following, but it might also use more memory
-  because the argument list cannot be deallocated incrementally.
-
-  Also, there seems to be a bug in this code or in the
-  implementation of obj_truncate.
-
-external obj_truncate : 'a array -> int -> unit = "caml_obj_truncate"
-
-let array_to_list_in_place a =
-  let l = Array.length a in
-  let rec loop accu n p =
-    if p <= 0 then accu else begin
-      if p = n then begin
-        obj_truncate a p;
-        loop (a.(p-1) :: accu) (n-1000) (p-1)
-      end else begin
-        loop (a.(p-1) :: accu) n (p-1)
-      end
-    end
-  in
-  loop [] (l-1000) l
-
-
-let stable_sort cmp l =
-  let a = Array.of_list l in
-  Array.stable_sort cmp a;
-  array_to_list_in_place a
-
-*/
-
-/* sorting + removing duplicates */
-
-let sort_uniq = (cmp, l) => {
-  let rec rev_merge = (l1, l2, accu) =>
-    switch (l1, l2) {
-    | (list{}, l2) => rev_append(l2, accu)
-    | (l1, list{}) => rev_append(l1, accu)
-    | (list{h1, ...t1}, list{h2, ...t2}) =>
-      let c = cmp(h1, h2)
-      if c == 0 {
-        rev_merge(t1, t2, list{h1, ...accu})
-      } else if c < 0 {
-        rev_merge(t1, l2, list{h1, ...accu})
-      } else {
-        rev_merge(l1, t2, list{h2, ...accu})
-      }
-    }
-
-  let rec rev_merge_rev = (l1, l2, accu) =>
-    switch (l1, l2) {
-    | (list{}, l2) => rev_append(l2, accu)
-    | (l1, list{}) => rev_append(l1, accu)
-    | (list{h1, ...t1}, list{h2, ...t2}) =>
-      let c = cmp(h1, h2)
-      if c == 0 {
-        rev_merge_rev(t1, t2, list{h1, ...accu})
-      } else if c > 0 {
-        rev_merge_rev(t1, l2, list{h1, ...accu})
-      } else {
-        rev_merge_rev(l1, t2, list{h2, ...accu})
-      }
+let rec filterMap = (xs, p) =>
+  switch xs {
+  | list{} => list{}
+  | list{h, ...t} =>
+    switch p(h) {
+    | Some(h) =>
+      let cell = mutableCell(h, list{})
+      copyAuxWitFilterMap(p, t, cell)
+      cell
+    | None => filterMap(t, p)
     }
+  }
 
-  let rec sort = (n, l) =>
-    switch (n, l) {
-    | (2, list{x1, x2, ..._}) =>
-      let c = cmp(x1, x2)
-      if c == 0 {
-        list{x1}
-      } else if c < 0 {
-        list{x1, x2}
-      } else {
-        list{x2, x1}
-      }
-    | (3, list{x1, x2, x3, ..._}) =>
-      let c = cmp(x1, x2)
-      if c == 0 {
-        let c = cmp(x2, x3)
-        if c == 0 {
-          list{x2}
-        } else if c < 0 {
-          list{x2, x3}
-        } else {
-          list{x3, x2}
-        }
-      } else if c < 0 {
-        let c = cmp(x2, x3)
-        if c == 0 {
-          list{x1, x2}
-        } else if c < 0 {
-          list{x1, x2, x3}
-        } else {
-          let c = cmp(x1, x3)
-          if c == 0 {
-            list{x1, x2}
-          } else if c < 0 {
-            list{x1, x3, x2}
-          } else {
-            list{x3, x1, x2}
-          }
-        }
-      } else {
-        let c = cmp(x1, x3)
-        if c == 0 {
-          list{x2, x1}
-        } else if c < 0 {
-          list{x2, x1, x3}
-        } else {
-          let c = cmp(x2, x3)
-          if c == 0 {
-            list{x2, x1}
-          } else if c < 0 {
-            list{x2, x3, x1}
-          } else {
-            list{x3, x2, x1}
-          }
-        }
-      }
-    | (n, l) =>
-      let n1 = asr(n, 1)
-      let n2 = n - n1
-      let l2 = chop(n1, l)
-      let s1 = rev_sort(n1, l)
-      let s2 = rev_sort(n2, l2)
-      rev_merge_rev(s1, s2, list{})
-    }
-  and rev_sort = (n, l) =>
-    switch (n, l) {
-    | (2, list{x1, x2, ..._}) =>
-      let c = cmp(x1, x2)
-      if c == 0 {
-        list{x1}
-      } else if c > 0 {
-        list{x1, x2}
-      } else {
-        list{x2, x1}
-      }
-    | (3, list{x1, x2, x3, ..._}) =>
-      let c = cmp(x1, x2)
-      if c == 0 {
-        let c = cmp(x2, x3)
-        if c == 0 {
-          list{x2}
-        } else if c > 0 {
-          list{x2, x3}
-        } else {
-          list{x3, x2}
-        }
-      } else if c > 0 {
-        let c = cmp(x2, x3)
-        if c == 0 {
-          list{x1, x2}
-        } else if c > 0 {
-          list{x1, x2, x3}
-        } else {
-          let c = cmp(x1, x3)
-          if c == 0 {
-            list{x1, x2}
-          } else if c > 0 {
-            list{x1, x3, x2}
-          } else {
-            list{x3, x1, x2}
-          }
-        }
-      } else {
-        let c = cmp(x1, x3)
-        if c == 0 {
-          list{x2, x1}
-        } else if c > 0 {
-          list{x2, x1, x3}
-        } else {
-          let c = cmp(x2, x3)
-          if c == 0 {
-            list{x2, x1}
-          } else if c > 0 {
-            list{x2, x3, x1}
-          } else {
-            list{x3, x2, x1}
-          }
-        }
-      }
-    | (n, l) =>
-      let n1 = asr(n, 1)
-      let n2 = n - n1
-      let l2 = chop(n1, l)
-      let s1 = sort(n1, l)
-      let s2 = sort(n2, l2)
-      rev_merge(s1, s2, list{})
+let partition = (l, p) =>
+  switch l {
+  | list{} => (list{}, list{})
+  | list{h, ...t} =>
+    let nextX = mutableCell(h, list{})
+    let nextY = mutableCell(h, list{})
+    let b = p(h)
+    partitionAux(p, t, nextX, nextY)
+    if b {
+      (
+        nextX,
+        switch nextY {
+        | list{_, ...tail} => tail
+        | list{} => assert(false)
+        },
+      )
+    } else {
+      (
+        switch nextX {
+        | list{_, ...tail} => tail
+        | list{} => assert(false)
+        },
+        nextY,
+      )
     }
-
-  let len = length(l)
-  if len < 2 {
-    l
-  } else {
-    sort(len, l)
   }
-}
 
-let rec compare_lengths = (l1, l2) =>
-  switch (l1, l2) {
-  | (list{}, list{}) => 0
-  | (list{}, _) => -1
-  | (_, list{}) => 1
-  | (list{_, ...l1}, list{_, ...l2}) => compare_lengths(l1, l2)
+let unzip = xs =>
+  switch xs {
+  | list{} => (list{}, list{})
+  | list{(x, y), ...l} =>
+    let cellX = mutableCell(x, list{})
+    let cellY = mutableCell(y, list{})
+    splitAux(l, cellX, cellY)
+    (cellX, cellY)
   }
 
-let rec compare_length_with = (l, n) =>
-  switch l {
-  | list{} =>
-    if n == 0 {
-      0
-    } else if n > 0 {
-      -1
-    } else {
-      1
-    }
-  | list{_, ...l} =>
-    if n <= 0 {
-      1
-    } else {
-      compare_length_with(l, n - 1)
-    }
+let zip = (l1, l2) =>
+  switch (l1, l2) {
+  | (_, list{}) | (list{}, _) => list{}
+  | (list{a1, ...l1}, list{a2, ...l2}) =>
+    let cell = mutableCell((a1, a2), list{})
+    zipAux(l1, l2, cell)
+    cell
   }
diff --git a/runtime/List.resi b/runtime/List.resi
index 1fdfd31f0c..095a31d693 100644
--- a/runtime/List.resi
+++ b/runtime/List.resi
@@ -1,365 +1,876 @@
-// FIXME:
-//   This exists for compatibility reason.
-//   Move this into Pervasives or Core
+/* Copyright (C) 2017 Authors of ReScript
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/**
+Collection functions for manipulating the `list` data structures, a singly-linked list.
+
+**Prefer Array** if you need any of the following:
+
+- Random access of element
+- Better interop with JavaScript
+- Better memory usage & performance.
+*/
+/** `'a t` is compatible with built-in `list` type */
+type t<'a> = list<'a>
 
-// Below is all deprecated and should be removed in v13
+/**
+`length(list)` returns the length of `list`.
 
-@deprecated("Use Core instead. This will be removed in v13")
-type t<'a> = list<'a>
+## Examples
+
+```rescript
+List.length(list{1, 2, 3}) // 3
+```
+*/
+let length: t<'a> => int
+
+/**
+`size(list)`. See [`length`](#length)
+
+## Examples
+
+```rescript
+List.size(list{1, 2, 3}) // 3
+```
+*/
+let size: t<'a> => int
+
+/**
+`head(list)` returns `Some(value)` where `value` is the first element in the
+list, or `None` if `list` is an empty list.
+
+## Examples
+
+```rescript
+List.head(list{}) // None
+List.head(list{1, 2, 3}) // Some(1)
+```
+*/
+let head: t<'a> => option<'a>
+
+/**
+`headExn(list)` same as [`head`](#head).
+
+## Examples
+
+```rescript
+List.headExn(list{1, 2, 3}) // 1
+
+List.headExn(list{}) // Raises an Error
+```
+
+## Exceptions
+
+- Raises an Error if list is empty.
+
+*/
+let headExn: t<'a> => 'a
+
+/**
+`tail(list)` returns `None` if `list` is empty, otherwise it returns `Some(tail)`
+where `tail` is everything except the first element of `list`.
+
+## Examples
+
+```rescript
+List.tail(list{1, 2, 3}) // Some(list{2, 3})
+
+List.tail(list{}) // None
+```
+*/
+let tail: t<'a> => option<t<'a>>
+
+/**
+`tailExn(list)` same as [`tail`](#tail).
+
+## Examples
+
+```rescript
+List.tailExn(list{1, 2, 3}) // list{2, 3}
+
+List.tailExn(list{}) // Raises an Error
+```
+
+## Exceptions
+
+- Raises an Error if list is empty.
+*/
+let tailExn: t<'a> => t<'a>
+
+/**
+`add(list, value)` adds a `value` to the beginning of list `list`.
+
+## Examples
+
+```rescript
+List.add(list{2, 3}, 1) // list{1, 2, 3}
+
+List.add(list{"World", "!"}, "Hello") // list{"Hello", "World", "!"}
+```
+*/
+let add: (t<'a>, 'a) => t<'a>
+
+/**
+`get(list, index)` return the `index` element in `list`, or `None` if `index`
+is larger than the length of list `list`.
+
+## Examples
+
+```rescript
+let abc = list{"A", "B", "C"}
+
+abc->List.get(1) // Some("B")
+
+abc->List.get(4) // None
+```
+*/
+let get: (t<'a>, int) => option<'a>
+
+/**
+`getExn(list, index)` same as [`get`](#get).
+
+## Examples
+
+```rescript
+let abc = list{"A", "B", "C"}
+
+abc->List.getExn(1) // "B"
+
+abc->List.getExn(4) // Raises an Error
+```
+
+## Exceptions
+
+- Raises an Error if `index` is larger than the length of list.
+*/
+let getExn: (t<'a>, int) => 'a
+
+/**
+`make(length, value)` returns a list of length `length` with each element filled
+with `value`. Returns an empty list if `value` is negative.
+
+## Examples
+
+```rescript
+List.make(~length=3, 1) // list{1, 1, 1}
+```
+*/
+let make: (~length: int, 'a) => t<'a>
+
+/**
+`makeBy(length, f)` return a list of length `length` with element initialized
+with `f`. Returns an empty list if `length` is negative.
+
+## Examples
+
+```rescript
+List.fromInitializer(~length=5, i => i) // list{0, 1, 2, 3, 4}
+
+List.fromInitializer(~length=5, i => i * i) // list{0, 1, 4, 9, 16}
+```
+*/
+let fromInitializer: (~length: int, int => 'a) => t<'a>
+
+/**
+`toShuffled(list)` returns a new list in random order.
+
+## Examples
+
+```rescript
+List.toShuffled(list{1, 2, 3}) // list{2, 1, 3}
+```
+*/
+let toShuffled: t<'a> => t<'a>
+
+/**
+`drop(list, value)` return a new list, dropping the first `value` element.
+Returns `None` if `list` has fewer than `value` elements.
+
+## Examples
+
+```rescript
+list{1, 2, 3}->List.drop(2) // Some(list{3})
+
+list{1, 2, 3}->List.drop(3) // Some(list{})
+
+list{1, 2, 3}->List.drop(4) // None
+```
+*/
+let drop: (t<'a>, int) => option<t<'a>>
+
+/**
+`take(list, value)` returns a list with the first `value` elements from `list`,
+or `None` if `list` has fewer than `value` elements.
+
+## Examples
+
+```rescript
+list{1, 2, 3}->List.take(1) // Some(list{1})
+
+list{1, 2, 3}->List.take(2) // Some(list{1, 2})
+
+list{1, 2, 3}->List.take(4) // None
+```
+*/
+let take: (t<'a>, int) => option<t<'a>>
+
+/**
+`splitAt(list, n)` split the list `list` at `n`. Returns `None` when the length
+of `list` is less than `n`.
+
+## Examples
+
+```rescript
+list{"Hello", "World"}->List.splitAt(1) // Some((list{"Hello"}, list{"World"}))
+
+list{0, 1, 2, 3, 4}->List.splitAt(2) // Some((list{0, 1}, list{2, 3, 4}))
+```
+*/
+let splitAt: (t<'a>, int) => option<(list<'a>, list<'a>)>
+
+/**
+`concat(list1, list2)` returns the list obtained by adding `list1` after `list2`.
+
+## Examples
+
+```rescript
+List.concat(list{1, 2, 3}, list{4, 5}) // list{1, 2, 3, 4, 5}
+```
+*/
+let concat: (t<'a>, t<'a>) => t<'a>
+
+/**
+`concatMany(arr)` returns the list obtained by concatenating all the lists in
+array `arr`, in order.
+
+## Examples
+
+```rescript
+List.concatMany([list{1, 2, 3}, list{}, list{3}]) // list{1, 2, 3, 3}
+```
+*/
+let concatMany: array<t<'a>> => t<'a>
+
+/**
+`reverseConcat(list1, list2)` is equivalent to writing: `concat(reverse(list1, list2)`
+
+## Examples
+
+```rescript
+List.reverseConcat(list{1, 2}, list{3, 4}) // list{2, 1, 3, 4}
+```
+*/
+let reverseConcat: (t<'a>, t<'a>) => t<'a>
+
+/**
+`flat(list)` return the list obtained by concatenating all the lists in
+`list`, in order.
+
+## Examples
+
+```rescript
+List.flat(list{list{1, 2, 3}, list{}, list{3}}) // list{1, 2, 3, 3}
+```
+*/
+let flat: t<t<'a>> => t<'a>
+
+/**
+`map(list, f)` returns a new list with `f` applied to each element of `list`.
+
+## Examples
+
+```rescript
+list{1, 2}->List.map(x => x + 1) // list{3, 4}
+```
+*/
+let map: (t<'a>, 'a => 'b) => t<'b>
+
+/**
+`zip(list1, list2)` returns a list of pairs from the two lists with the length
+of the shorter list.
+
+## Examples
+
+```rescript
+List.zip(list{1, 2}, list{3, 4, 5}) // list{(1, 3), (2, 4)}
+```
+*/
+let zip: (t<'a>, t<'b>) => t<('a, 'b)>
+
+/**
+`zipBy(list1, list2, f)`. See [`zip`](#zip)
+
+## Examples
+
+```rescript
+List.zipBy(list{1, 2, 3}, list{4, 5}, (a, b) => 2 * a + b) // list{6, 9}
+```
+*/
+let zipBy: (t<'a>, t<'b>, ('a, 'b) => 'c) => t<'c>
+
+/**
+`mapWithIndex(list, f)` applies `f` to each element of `list`. Function `f`
+takes two arguments: the index starting from 0 and the element from `list`, in
+that order.
+
+## Examples
+
+```rescript
+list{1, 2, 3}->List.mapWithIndex((x, index) => index + x) // list{1, 3, 5}
+```
+*/
+let mapWithIndex: (t<'a>, ('a, int) => 'b) => t<'b>
+
+/**
+`fromArray(arr)` converts the given array `arr` to a list.
+
+## Examples
+
+```rescript
+List.fromArray([1, 2, 3]) // list{1, 2, 3}
+```
+*/
+let fromArray: array<'a> => t<'a>
+
+/**
+`toArray(list)` converts the given list `list` to an array.
+
+## Examples
+
+```rescript
+List.toArray(list{1, 2, 3}) // [1, 2, 3]
+```
+*/
+let toArray: t<'a> => array<'a>
+
+/* type json = Js_json.t */
+
+/* val toJson : 'a t -> ('a -> json  [@bs]) -> json */
+/* val fromJson : json -> (json -> 'a [@bs]) -> 'a t */
+
+/**
+`reverse(list)` returns a new list whose elements are those of `list` in
+reversed order.
+
+## Examples
+
+```rescript
+List.reverse(list{1, 2, 3}) // list{3, 2, 1}
+```
+*/
+let reverse: t<'a> => t<'a>
+
+/**
+`mapReverse(list, f)` is equivalent to `map` function.
+
+## Examples
+
+```rescript
+let f = x => x * x
+let l = list{3, 4, 5}
+
+let withMap = List.map(l, f)->List.reverse
+let withMapReverse = l->List.mapReverse(f)
+
+Console.log(withMap == withMapReverse) // true
+```
+*/
+let mapReverse: (t<'a>, 'a => 'b) => t<'b>
+
+/**
+`forEach(list, f)` call `f` on each element of `list` from the beginning to end.
+`f` returns `unit`, so no new array is created. Use `forEach` when you are primarily
+concerned with repetitively creating side effects.
+
+## Examples
+
+```rescript
+List.forEach(list{"a", "b", "c"}, x => Console.log("Item: " ++ x))
+/*
+  prints:
+  Item: a
+  Item: b
+  Item: c
+*/
+```
+*/
+let forEach: (t<'a>, 'a => unit) => unit
+
+/**
+`forEachWithIndex(list, f, index)` call `f` on each element of `list` from beginning
+to end. Function `f` takes two arguments: the `index` starting from 0 and the
+element from `list`. `f` returns `unit`.
+
+## Examples
+
+```rescript
+List.forEachWithIndex(list{"a", "b", "c"}, (x, index) => {
+  Console.log("Item " ++ Int.toString(index) ++ " is " ++ x)
+})
+/*
+  prints:
+  Item 0 is a
+  Item 1 is b
+  Item 2 is cc
+*/
+```
+*/
+let forEachWithIndex: (t<'a>, ('a, int) => unit) => unit
+
+/**
+`reduce(list, initialValue, f)` applies `f` to each element of `list` from
+beginning to end. Function `f` has two parameters: the item from the list and
+an "accumulator", which starts with a value of `initialValue`. `reduce` returns
+the final value of the accumulator.
+
+## Examples
 
-/** Return the length (number of elements) of the given list. */
-@deprecated("Use Core instead. This will be removed in v13")
-let length: list<'a> => int
-
-/** Compare the lengths of two lists. [compare_lengths l1 l2] is
-   equivalent to [compare (length l1) (length l2)], except that
-   the computation stops after itering on the shortest list.
-   @since 4.05.0
- */
-@deprecated("Use Core instead. This will be removed in v13")
-let compare_lengths: (list<'a>, list<'b>) => int
-
-/** Compare the length of a list to an integer. [compare_length_with l n] is
-   equivalent to [compare (length l) n], except that
-   the computation stops after at most [n] iterations on the list.
-   @since 4.05.0
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let compare_length_with: (list<'a>, int) => int
-
-/** [cons x xs] is [x :: xs]
-    @since 4.03.0
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let cons: ('a, list<'a>) => list<'a>
-
-/** Return the first element of the given list. Raise
-   [Failure "hd"] if the list is empty. */
-@deprecated("Use Core instead. This will be removed in v13")
-let hd: list<'a> => 'a
-
-/** Return the given list without its first element. Raise
-    [Failure "tl"] if the list is empty. */
-@deprecated("Use Core instead. This will be removed in v13")
-let tl: list<'a> => list<'a>
-
-/** Return the [n]-th element of the given list.
-   The first element (head of the list) is at position 0.
-   Raise [Failure "nth"] if the list is too short.
-   Raise [Invalid_argument "List.nth"] if [n] is negative. */
-@deprecated("Use Core instead. This will be removed in v13")
-let nth: (list<'a>, int) => 'a
-
-/** Return the [n]-th element of the given list.
-    The first element (head of the list) is at position 0.
-    Return [None] if the list is too short.
-    Raise [Invalid_argument "List.nth"] if [n] is negative.
-    @since 4.05
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let nth_opt: (list<'a>, int) => option<'a>
-
-/** List reversal. */
-@deprecated("Use Core instead. This will be removed in v13")
-let rev: list<'a> => list<'a>
-
-/** [List.init len f] is [f 0; f 1; ...; f (len-1)], evaluated left to right.
-
-    @raise Invalid_argument if len < 0.
-    @since 4.06.0
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let init: (int, int => 'a) => list<'a>
-
-/** Concatenate two lists.  Same as the infix operator [@].
-   Not tail-recursive (length of the first argument).  */
-@deprecated("Use Core instead. This will be removed in v13")
-let append: (list<'a>, list<'a>) => list<'a>
-
-/** [List.rev_append l1 l2] reverses [l1] and concatenates it to [l2].
-   This is equivalent to {!List.rev}[ l1 @ l2], but [rev_append] is
-   tail-recursive and more efficient. */
-@deprecated("Use Core instead. This will be removed in v13")
-let rev_append: (list<'a>, list<'a>) => list<'a>
-
-/** Concatenate a list of lists.  The elements of the argument are all
-   concatenated together (in the same order) to give the result.
-   Not tail-recursive
-   (length of the argument + length of the longest sub-list). */
-@deprecated("Use Core instead. This will be removed in v13")
-let concat: list<list<'a>> => list<'a>
-
-/** An alias for [concat]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let flatten: list<list<'a>> => list<'a>
-
-/* {1 Iterators} */
-
-/** [List.iter f [a1; ...; an]] applies function [f] in turn to
-   [a1; ...; an]. It is equivalent to
-   [begin f a1; f a2; ...; f an; () end]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let iter: ('a => unit, list<'a>) => unit
-
-/** Same as {!List.iter}, but the function is applied to the index of
-   the element as first argument (counting from 0), and the element
-   itself as second argument.
-   @since 4.00.0
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let iteri: ((int, 'a) => unit, list<'a>) => unit
-
-/** [List.map f [a1; ...; an]] applies function [f] to [a1, ..., an],
-   and builds the list [[f a1; ...; f an]]
-   with the results returned by [f].  Not tail-recursive. */
-@deprecated("Use Core instead. This will be removed in v13")
-let map: ('a => 'b, list<'a>) => list<'b>
-
-/** Same as {!List.map}, but the function is applied to the index of
-   the element as first argument (counting from 0), and the element
-   itself as second argument.  Not tail-recursive.
-   @since 4.00.0
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let mapi: ((int, 'a) => 'b, list<'a>) => list<'b>
-
-/** [List.rev_map f l] gives the same result as
-   {!List.rev}[ (]{!List.map}[ f l)], but is tail-recursive and
-   more efficient. */
-@deprecated("Use Core instead. This will be removed in v13")
-let rev_map: ('a => 'b, list<'a>) => list<'b>
-
-/** [List.fold_left f a [b1; ...; bn]] is
-   [f (... (f (f a b1) b2) ...) bn]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let fold_left: (('a, 'b) => 'a, 'a, list<'b>) => 'a
-
-/** [List.fold_right f [a1; ...; an] b] is
-   [f a1 (f a2 (... (f an b) ...))].  Not tail-recursive. */
-@deprecated("Use Core instead. This will be removed in v13")
-let fold_right: (('a, 'b) => 'b, list<'a>, 'b) => 'b
-
-/* {1 Iterators on two lists} */
-
-/** [List.iter2 f [a1; ...; an] [b1; ...; bn]] calls in turn
-   [f a1 b1; ...; f an bn].
-   Raise [Invalid_argument] if the two lists are determined
-   to have different lengths. */
-@deprecated("Use Core instead. This will be removed in v13")
-let iter2: (('a, 'b) => unit, list<'a>, list<'b>) => unit
-
-/** [List.map2 f [a1; ...; an] [b1; ...; bn]] is
-   [[f a1 b1; ...; f an bn]].
-   Raise [Invalid_argument] if the two lists are determined
-   to have different lengths.  Not tail-recursive. */
-@deprecated("Use Core instead. This will be removed in v13")
-let map2: (('a, 'b) => 'c, list<'a>, list<'b>) => list<'c>
-
-/** [List.rev_map2 f l1 l2] gives the same result as
-   {!List.rev}[ (]{!List.map2}[ f l1 l2)], but is tail-recursive and
-   more efficient. */
-@deprecated("Use Core instead. This will be removed in v13")
-let rev_map2: (('a, 'b) => 'c, list<'a>, list<'b>) => list<'c>
-
-/** [List.fold_left2 f a [b1; ...; bn] [c1; ...; cn]] is
-   [f (... (f (f a b1 c1) b2 c2) ...) bn cn].
-   Raise [Invalid_argument] if the two lists are determined
-   to have different lengths. */
-@deprecated("Use Core instead. This will be removed in v13")
-let fold_left2: (('a, 'b, 'c) => 'a, 'a, list<'b>, list<'c>) => 'a
-
-/** [List.fold_right2 f [a1; ...; an] [b1; ...; bn] c] is
-   [f a1 b1 (f a2 b2 (... (f an bn c) ...))].
-   Raise [Invalid_argument] if the two lists are determined
-   to have different lengths.  Not tail-recursive. */
-@deprecated("Use Core instead. This will be removed in v13")
-let fold_right2: (('a, 'b, 'c) => 'c, list<'a>, list<'b>, 'c) => 'c
-
-/* {1 List scanning} */
-
-/** [for_all p [a1; ...; an]] checks if all elements of the list
-   satisfy the predicate [p]. That is, it returns
-   [(p a1) && (p a2) && ... && (p an)]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let for_all: ('a => bool, list<'a>) => bool
-
-/** [exists p [a1; ...; an]] checks if at least one element of
-   the list satisfies the predicate [p]. That is, it returns
-   [(p a1) || (p a2) || ... || (p an)]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let exists: ('a => bool, list<'a>) => bool
-
-/** Same as {!List.for_all}, but for a two-argument predicate.
-   Raise [Invalid_argument] if the two lists are determined
-   to have different lengths. */
-@deprecated("Use Core instead. This will be removed in v13")
-let for_all2: (('a, 'b) => bool, list<'a>, list<'b>) => bool
-
-/** Same as {!List.exists}, but for a two-argument predicate.
-   Raise [Invalid_argument] if the two lists are determined
-   to have different lengths. */
-@deprecated("Use Core instead. This will be removed in v13")
-let exists2: (('a, 'b) => bool, list<'a>, list<'b>) => bool
-
-/** [mem a l] is true if and only if [a] is equal
-   to an element of [l]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let mem: ('a, list<'a>) => bool
-
-/** Same as {!List.mem}, but uses physical equality instead of structural
-   equality to compare list elements. */
-@deprecated("Use Core instead. This will be removed in v13")
-let memq: ('a, list<'a>) => bool
-
-/* {1 List searching} */
-
-/** [find p l] returns the first element of the list [l]
-   that satisfies the predicate [p].
-   Raise [Not_found] if there is no value that satisfies [p] in the
-   list [l]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let find: ('a => bool, list<'a>) => 'a
-
-/** [find_opt p l] returns the first element of the list [l] that
-    satisfies the predicate [p], or [None] if there is no value that
-    satisfies [p] in the list [l].
-    @since 4.05 */
-@deprecated("Use Core instead. This will be removed in v13")
-let find_opt: ('a => bool, list<'a>) => option<'a>
-
-/** [filter p l] returns all the elements of the list [l]
-   that satisfy the predicate [p].  The order of the elements
-   in the input list is preserved.  */
-@deprecated("Use Core instead. This will be removed in v13")
-let filter: ('a => bool, list<'a>) => list<'a>
-
-/** [find_all] is another name for {!List.filter}. */
-let find_all: ('a => bool, list<'a>) => list<'a>
-
-/** [partition p l] returns a pair of lists [(l1, l2)], where
-   [l1] is the list of all the elements of [l] that
-   satisfy the predicate [p], and [l2] is the list of all the
-   elements of [l] that do not satisfy [p].
-   The order of the elements in the input list is preserved. */
-@deprecated("Use Core instead. This will be removed in v13")
-let partition: ('a => bool, list<'a>) => (list<'a>, list<'a>)
-
-/* {1 Association lists} */
-
-/** [assoc a l] returns the value associated with key [a] in the list of
-   pairs [l]. That is,
-   [assoc a [ ...; (a,b); ...] = b]
-   if [(a,b)] is the leftmost binding of [a] in list [l].
-   Raise [Not_found] if there is no value associated with [a] in the
-   list [l]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let assoc: ('a, list<('a, 'b)>) => 'b
-
-/** [assoc_opt a l] returns the value associated with key [a] in the list of
-   pairs [l]. That is,
-   [assoc_opt a [ ...; (a,b); ...] = b]
-   if [(a,b)] is the leftmost binding of [a] in list [l].
-   Returns [None] if there is no value associated with [a] in the
-   list [l].
-   @since 4.05 */
-@deprecated("Use Core instead. This will be removed in v13")
-let assoc_opt: ('a, list<('a, 'b)>) => option<'b>
-
-/** Same as {!List.assoc}, but uses physical equality instead of structural
-   equality to compare keys. */
-@deprecated("Use Core instead. This will be removed in v13")
-let assq: ('a, list<('a, 'b)>) => 'b
-
-/** Same as {!List.assoc_opt}, but uses physical equality instead of structural
-    equality to compare keys.
-    @since 4.05 */
-@deprecated("Use Core instead. This will be removed in v13")
-let assq_opt: ('a, list<('a, 'b)>) => option<'b>
-
-/** Same as {!List.assoc}, but simply return true if a binding exists,
-   and false if no bindings exist for the given key. */
-@deprecated("Use Core instead. This will be removed in v13")
-let mem_assoc: ('a, list<('a, 'b)>) => bool
-
-/** Same as {!List.mem_assoc}, but uses physical equality instead of
-   structural equality to compare keys. */
-@deprecated("Use Core instead. This will be removed in v13")
-let mem_assq: ('a, list<('a, 'b)>) => bool
-
-/** [remove_assoc a l] returns the list of
-   pairs [l] without the first pair with key [a], if any.
-   Not tail-recursive. */
-@deprecated("Use Core instead. This will be removed in v13")
-let remove_assoc: ('a, list<('a, 'b)>) => list<('a, 'b)>
-
-/** Same as {!List.remove_assoc}, but uses physical equality instead
-   of structural equality to compare keys.  Not tail-recursive. */
-@deprecated("Use Core instead. This will be removed in v13")
-let remove_assq: ('a, list<('a, 'b)>) => list<('a, 'b)>
-
-/* {1 Lists of pairs} */
-
-/** Transform a list of pairs into a pair of lists:
-   [split [(a1,b1); ...; (an,bn)]] is [([a1; ...; an], [b1; ...; bn])].
-   Not tail-recursive.
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let split: list<('a, 'b)> => (list<'a>, list<'b>)
-
-/** Transform a pair of lists into a list of pairs:
-   [combine [a1; ...; an] [b1; ...; bn]] is
-   [[(a1,b1); ...; (an,bn)]].
-   Raise [Invalid_argument] if the two lists
-   have different lengths.  Not tail-recursive. */
-@deprecated("Use Core instead. This will be removed in v13")
-let combine: (list<'a>, list<'b>) => list<('a, 'b)>
-
-/* {1 Sorting} */
-
-/** Sort a list in increasing order according to a comparison
-   function.  The comparison function must return 0 if its arguments
-   compare as equal, a positive integer if the first is greater,
-   and a negative integer if the first is smaller (see Array.sort for
-   a complete specification).  For example,
-   {!Pervasives.compare} is a suitable comparison function.
-   The resulting list is sorted in increasing order.
-   [List.sort] is guaranteed to run in constant heap space
-   (in addition to the size of the result list) and logarithmic
-   stack space.
-
-   The current implementation uses Merge Sort. It runs in constant
-   heap space and logarithmic stack space.
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let sort: (('a, 'a) => int, list<'a>) => list<'a>
-
-/** Same as {!List.sort}, but the sorting algorithm is guaranteed to
-   be stable (i.e. elements that compare equal are kept in their
-   original order) .
-
-   The current implementation uses Merge Sort. It runs in constant
-   heap space and logarithmic stack space.
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let stable_sort: (('a, 'a) => int, list<'a>) => list<'a>
-
-/** Same as {!List.sort} or {!List.stable_sort}, whichever is faster
-    on typical input. */
-@deprecated("Use Core instead. This will be removed in v13")
-let fast_sort: (('a, 'a) => int, list<'a>) => list<'a>
-
-/** Same as {!List.sort}, but also remove duplicates.
-    @since 4.02.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let sort_uniq: (('a, 'a) => int, list<'a>) => list<'a>
-
-/** Merge two lists:
-    Assuming that [l1] and [l2] are sorted according to the
-    comparison function [cmp], [merge cmp l1 l2] will return a
-    sorted list containing all the elements of [l1] and [l2].
-    If several elements compare equal, the elements of [l1] will be
-    before the elements of [l2].
-    Not tail-recursive (sum of the lengths of the arguments).
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let merge: (('a, 'a) => int, list<'a>, list<'a>) => list<'a>
+```rescript
+list{1, 2, 3, 4}->List.reduce(0, (a, b) => a + b) // 10
+
+// same as
+
+list{1, 2, 3, 4}->List.reduce(0, (acc, item) => acc + item) // 10
+```
+*/
+let reduce: (t<'a>, 'b, ('b, 'a) => 'b) => 'b
+
+/**
+`reduceWithIndex(list, initialValue, f)` applies `f` to each element of `list`
+from beginning to end. Function `f` has three parameters: the item from the list
+and an "accumulator", which starts with a value of `initialValue` and the index
+of each element. `reduceWithIndex` returns the final value of the accumulator.
+
+## Examples
+
+```rescript
+list{1, 2, 3, 4}->List.reduceWithIndex(0, (acc, item, index) => acc + item + index) // 16
+```
+*/
+let reduceWithIndex: (t<'a>, 'b, ('b, 'a, int) => 'b) => 'b
+
+/**
+`reduceReverse(list, initialValue, f)` works like `reduce`, except that
+function `f` is applied to each item of `list` from the last back to the first.
+
+## Examples
+
+```rescript
+list{1, 2, 3, 4}->List.reduceReverse(0, (a, b) => a + b) // 10
+
+list{1, 2, 3, 4}->List.reduceReverse(10, (a, b) => a - b) // 0
+
+list{1, 2, 3, 4}->List.reduceReverse(list{}, List.add) // list{1, 2, 3, 4}
+```
+*/
+let reduceReverse: (t<'a>, 'b, ('b, 'a) => 'b) => 'b
+
+/**
+`mapReverse2(list1, list2, f)` is equivalent to `List.zipBy(list1, list2, f)->List.reverse`.
+
+## Examples
+
+```rescript
+List.mapReverse2(list{1, 2, 3}, list{1, 2}, (a, b) => a + b) // list{4, 2}
+```
+*/
+let mapReverse2: (t<'a>, t<'b>, ('a, 'b) => 'c) => t<'c>
+
+/**
+`forEach2(list1, list2, f)` is similar to `forEach`, but accepts two lists and
+stops at the length of the shorter list.
+
+## Examples
+
+```rescript
+List.forEach2(list{"Z", "Y"}, list{"A", "B", "C"}, (x, y) => Console.log2(x, y))
+
+/*
+  prints:
+  "Z" "A"
+  "Y" "B"
+*/
+```
+*/
+let forEach2: (t<'a>, t<'b>, ('a, 'b) => 'c) => unit
+
+/**
+`reduce2(list1, list2, initialValue, f)` applies `f` to each element of `list1`
+and `list2` from beginning to end. Stops with the shorter list. Function `f` has
+three parameters: an accumulator which starts with a value of `initialValue`, an
+item from `l1`, and an item from `l2`. `reduce2` returns the final value of the
+accumulator.
+
+## Examples
+
+```rescript
+List.reduce2(list{1, 2, 3}, list{4, 5}, 0, (acc, x, y) => acc + x * x + y) // 0 + (1 * 1 + 4) + (2 * 2 + 5)
+```
+*/
+let reduce2: (t<'b>, t<'c>, 'a, ('a, 'b, 'c) => 'a) => 'a
+
+/**
+`reduceReverse2(list1, list2, initialValue, f)` applies `f` to each element of
+`list1` and `list2`from end to beginning. Stops with the shorter list. Function
+`f` has three parameters: an accumulator which starts with a value of
+`initialValue`, an item from `l1`, and an item from `l2`. `reduce2` returns the
+final value of the accumulator.
+
+## Examples
+
+```rescript
+List.reduceReverse2(list{1, 2, 3}, list{4, 5}, 0, (acc, x, y) => acc + x * x + y) //  + (1 * 1 + 4) + (2 * 2 + 5)
+```
+*/
+let reduceReverse2: (t<'a>, t<'b>, 'c, ('c, 'a, 'b) => 'c) => 'c
+
+/**
+`every(list, f)` returns `true` if all elements in `list` satisfy `f`, where `f`
+is a predicate: a function taking an element and returning a bool.
+
+## Examples
+
+```rescript
+let isBelow10 = value => value < 10
+
+list{1, 9, 8, 2}->List.every(isBelow10) // true
+
+list{1, 99, 8, 2}->List.every(isBelow10) // false
+```
+*/
+let every: (t<'a>, 'a => bool) => bool
+
+/**
+`some(list, f)` returns `true` if at least _one_ of the elements in `list`
+satisfies `f`, where `f` is a predicate: a function taking an element and
+returning a bool.
+
+## Examples
+
+```rescript
+let isAbove100 = value => value > 100
+
+list{101, 1, 2, 3}->List.some(isAbove100) // true
+
+list{1, 2, 3, 4}->List.some(isAbove100) // false
+```
+*/
+let some: (t<'a>, 'a => bool) => bool
+
+/**
+`every2(list1, list2, f)` returns `true` if predicate `f` is `true` for all
+pairs of elements up to the shorter length (i.e. `min(length(list1), length(list2))`)
+
+## Examples
+
+```rescript
+List.every2(list{1, 2, 3}, list{0, 1}, (a, b) => a > b) // true
+
+List.every2(list{}, list{1}, (a, b) => a > b) // true
+
+List.every2(list{2, 3}, list{1}, (a, b) => a > b) // true
+
+List.every2(list{0, 1}, list{5, 0}, (a, b) => a > b) // false
+```
+*/
+let every2: (t<'a>, t<'b>, ('a, 'b) => bool) => bool
+
+/**
+`some2(list1, list2, f)` returns `true` if predicate `f` is `true` for any pair
+of elements up to the shorter length (i.e. `min(length(list1), length(list2))`)
+
+## Examples
+
+```rescript
+List.some2(list{1, 2, 3}, list{0, 1}, (a, b) => a > b) // true
+
+List.some2(list{}, list{1}, (a, b) => a > b) // false
+
+List.some2(list{2, 3}, list{1}, (a, b) => a > b) // true
+
+List.some2(list{0, 1}, list{5, 0}, (a, b) => a > b) // true
+```
+*/
+let some2: (t<'a>, t<'b>, ('a, 'b) => bool) => bool
+
+/**
+`compareLength(list1, list2)` compare two lists solely by length. Returns `-1.` if
+`length(list1)` is less than `length(list2)`, `0.` if `length(list1)` equals
+`length(list2)`, and `1.` if `length(list1)` is greater than `length(list2)`.
+
+## Examples
+
+```rescript
+List.compareLength(list{1, 2}, list{3, 4, 5, 6}) // -1.
+
+List.compareLength(list{1, 2, 3}, list{4, 5, 6}) // 0.
+
+List.compareLength(list{1, 2, 3, 4}, list{5, 6}) // 1.
+```
+*/
+let compareLength: (t<'a>, t<'a>) => Ordering.t
+
+/**
+`compare(list1, list2, f)` compare elements one by one `f`. `f` returns a negative
+number if `list1` is "less than" `list2`, zero if `list1` is "equal to" `list2`,
+a positive number if `list1` is "greater than" `list2`.
+
+The comparison returns the first non-zero result of `f`, or zero if `f` returns
+zero for all `list1` and `list2`.
+
+- If all items have compared equal, but `list1` is exhausted first, return `-1.`. (`list1` is shorter).
+- If all items have compared equal, but `list2` is exhausted first, return `1.` (`list1` is longer).
+
+## Examples
+
+```rescript
+List.compare(list{3}, list{3, 7}, (a, b) => Int.compare(a, b)) // -1.
+List.compare(list{5, 3}, list{5}, (a, b) => Int.compare(a, b)) // 1.
+List.compare(list{1, 3, 5}, list{1, 4, 2}, (a, b) => Int.compare(a, b)) // -1.
+List.compare(list{1, 3, 5}, list{1, 2, 3}, (a, b) => Int.compare(a, b)) // 1.
+List.compare(list{1, 3, 5}, list{1, 3, 5}, (a, b) => Int.compare(a, b)) // 0.
+```
+
+**Please note:** The total ordering of List is different from Array,
+for Array, we compare the length first and, only if the lengths are equal, elements one by one.
+For lists, we just compare elements one by one.
+*/
+let compare: (t<'a>, t<'a>, ('a, 'a) => Ordering.t) => Ordering.t
+
+/**
+`equal(list1, list2, f)` check equality of `list2` and `list2` using `f` for
+equality on elements, where `f` is a function that returns `true` if items `x` and
+`y` meet some criterion for equality, `false` otherwise. equal `false` if length
+of `list1` and `list2` are not the same.
+
+## Examples
+
+```rescript
+List.equal(list{1, 2, 3}, list{1, 2}, (a, b) => a == b) // false
+
+List.equal(list{1, 2}, list{1, 2}, (a, b) => a == b) // true
+
+List.equal(list{1, 2, 3}, list{(-1), (-2), (-3)}, (a, b) => abs(a) == abs(b)) // true
+```
+*/
+let equal: (t<'a>, t<'a>, ('a, 'a) => bool) => bool
+
+/**
+`has(list, element, f)` returns `true` if the list contains at least one
+`element` for which `f` returns `true'.
+
+## Examples
+
+```rescript
+list{1, 2, 3}->List.has(2, (a, b) => a == b) // true
+
+list{1, 2, 3}->List.has(4, (a, b) => a == b) // false
+
+list{(-1), (-2), (-3)}->List.has(2, (a, b) => abs(a) == abs(b)) // true
+```
+*/
+let has: (t<'a>, 'b, ('a, 'b) => bool) => bool
+
+/**
+`find(list, f)` returns `Some(value)` for the first value in `list` that
+satisfies the predicate function `f`. Returns `None` if no element satisfies
+the function.
+
+## Examples
+
+```rescript
+List.find(list{1, 4, 3, 2}, x => x > 3) // Some(4)
+
+List.find(list{1, 4, 3, 2}, x => x > 4) // None
+```
+*/
+let find: (t<'a>, 'a => bool) => option<'a>
+
+/**
+`filter(list, f)` returns a list of all elements in `list` which satisfy the
+predicate function `f`.
+
+## Examples
+
+```rescript
+let isEven = x => mod(x, 2) == 0
+
+List.filter(list{1, 2, 3, 4}, isEven) // list{2, 4}
+
+List.filter(list{None, Some(2), Some(3), None}, Option.isSome) // list{Some(2), Some(3)}
+```
+*/
+let filter: (t<'a>, 'a => bool) => t<'a>
+
+/**
+`filterWithIndex(list, f)` returns a list of all elements in `list` which
+satisfy the predicate function `f`.
+
+## Examples
+
+```rescript
+let isEven = x => mod(x, 2) == 0
+
+List.filterWithIndex(list{1, 2, 3, 4}, (_x, index) => isEven(index)) // list{1, 3}
+```
+*/
+let filterWithIndex: (t<'a>, ('a, int) => bool) => t<'a>
+
+/**
+`filterMap(list, f)` applies `f` to each element of `list`. If `f` returns
+`Some(value)`, then `value` is _kept_ in the resulting list. If `f` returns
+`None`, the element is _not_ retained in the result.
+
+## Examples
+
+```rescript
+let isEven = x => mod(x, 2) == 0
+
+list{1, 2, 3, 4}
+->List.filterMap(x =>
+    if (isEven(x)) {
+      Some(x)
+    } else {
+      None
+    }
+  ) // list{2, 4}
+
+list{Some(1), Some(2), None}->List.filterMap(x => x) // list{1, 2}
+```
+*/
+let filterMap: (t<'a>, 'a => option<'b>) => t<'b>
+
+/**
+`partition(list, f)` creates a pair of lists; the first list consists of all
+elements of `list` that satisfy the predicate function `f`, the second list
+consists of all elements of `list` that _do not_ satisfy `f`.
+
+## Examples
+
+```rescript
+// (elementsThatSatisfies, elementsThatDoesNotSatisfy)
+
+List.partition(list{1, 2, 3, 4}, x => x > 2) // (list{3, 4}, list{1, 2})
+```
+*/
+let partition: (t<'a>, 'a => bool) => (t<'a>, t<'a>)
+
+/**
+`unzip(list)` takes a list of pairs and creates a pair of lists. The first list
+contains all the first items of the pairs, the second list contains all the
+second items.
+
+## Examples
+
+```rescript
+List.unzip(list{(1, 2), (3, 4)}) // (list{1, 3}, list{2, 4})
+
+List.unzip(list{("H", "W"), ("e", "o"), ("l", "r"), ("l", "l"), ("o", "d"), (" ", "!")})
+// (list{"H", "e", "l", "l", "o", " "}, list{"W", "o", "r", "l", "d", "!"})
+```
+*/
+let unzip: t<('a, 'b)> => (t<'a>, t<'b>)
+
+/**
+`getAssoc(list, k, f)` return the second element of a pair in `list` where
+the first element equals `k` as per the predicate function `f`, or `None` if
+not found.
+
+## Examples
+
+```rescript
+list{(1, "a"), (2, "b"), (3, "c")}->List.getAssoc(3, (a, b) => a == b) // Some("c")
+
+list{(9, "morning"), (15, "afternoon"), (22, "night")}
+->List.getAssoc(15, (k, item) => k /* 15 */ == item /* 9, 5, 22 */)
+// Some("afternoon")
+```
+*/
+let getAssoc: (t<('a, 'c)>, 'b, ('a, 'b) => bool) => option<'c>
+
+/**
+`hasAssoc(list, k, f)` returns `true` if there is a pair in `list` where the
+first element equals `k` as per the predicate function `f`.
+
+## Examples
+
+```rescript
+list{(1, "a"), (2, "b"), (3, "c")}->List.hasAssoc(1, (a, b) => a == b) // true
+
+list{(9, "morning"), (15, "afternoon"), (22, "night")}
+->List.hasAssoc(25, (k, item) => k /* 25 */ == item /* 9, 5, 22 */) // false
+```
+*/
+let hasAssoc: (t<('a, 'c)>, 'b, ('a, 'b) => bool) => bool
+
+/**
+`removeAssoc(list, k, f)` return a list after removing the first pair whose
+first value is `k` per the equality predicate `f`, if not found, return a new
+list identical to `list`.
+
+## Examples
+
+```rescript
+list{(1, "a"), (2, "b"), (3, "c")}->List.removeAssoc(1, (a, b) => a == b) // list{(2, "b"), (3, "c")}
+
+list{(9, "morning"), (15, "afternoon"), (22, "night")}
+->List.removeAssoc(9, (k, item) => k /* 9 */ == item /* 9, 5, 22 */)
+// list{(15, "afternoon"), (22, "night")}
+```
+*/
+let removeAssoc: (t<('a, 'c)>, 'b, ('a, 'b) => bool) => t<('a, 'c)>
+
+/**
+`setAssoc(list, k, v, f)`. If `k` exists in `list` by satisfying the `f`
+predicate, return a new list with the key and value replaced by the new `k` and
+`v`, otherwise, return a new list with the pair `k`, `v` added to the head of
+`list`.
+
+## Examples
+
+```rescript
+list{(1, "a"), (2, "b"), (3, "c")}->List.setAssoc(2, "x", (a, b) => a == b) // list{(1, "a"), (2, "x"), (3, "c")}
+
+list{(1, "a"), (3, "c")}->List.setAssoc(2, "b", (a, b) => a == b) // list{(2, "b"), (1, "a"), (3, "c")}
+
+list{(9, "morning"), (3, "morning?!"), (22, "night")}
+->List.setAssoc(15, "afternoon", (a, b) => mod(a, 12) == mod(b, 12))
+// list{(9, "morning"), (15, "afternoon"), (22, "night")}
+```
+
+**Please note**: In the last example, since: `15 mod 12` equals `3 mod 12`. Both
+the key _and_ the value are replaced in the list.
+*/
+let setAssoc: (t<('a, 'c)>, 'a, 'c, ('a, 'a) => bool) => t<('a, 'c)>
+
+/**
+`sort(list, f)` returns a sorted list.
+
+## Examples
+
+```rescript
+List.sort(list{5, 4, 9, 3, 7}, Int.compare) // list{3, 4, 5, 7, 9}
+```
+*/
+let sort: (t<'a>, ('a, 'a) => Ordering.t) => t<'a>
diff --git a/runtime/Map.res b/runtime/Map.res
index b547fe31de..a6fa75344c 100644
--- a/runtime/Map.res
+++ b/runtime/Map.res
@@ -1,4 +1,21 @@
-// FIXME:
-//   This exists for compatibility reason.
-//   Move this into Pervasives or Core
+type t<'k, 'v> = Js.Map.t<'k, 'v>
 
+@new external make: unit => t<'k, 'v> = "Map"
+@new external fromArray: array<('k, 'v)> => t<'k, 'v> = "Map"
+@new external fromIterator: Iterator.t<('k, 'v)> => t<'k, 'v> = "Map"
+
+@get external size: t<'k, 'v> => int = "size"
+
+@send external clear: t<'k, 'v> => unit = "clear"
+
+@send external forEach: (t<'k, 'v>, 'v => unit) => unit = "forEach"
+@send external forEachWithKey: (t<'k, 'v>, ('v, 'k) => unit) => unit = "forEach"
+
+@send external get: (t<'k, 'v>, 'k) => option<'v> = "get"
+@send external has: (t<'k, 'v>, 'k) => bool = "has"
+@send external set: (t<'k, 'v>, 'k, 'v) => unit = "set"
+@send external delete: (t<'k, 'v>, 'k) => bool = "delete"
+
+@send external keys: t<'k, 'v> => Iterator.t<'k> = "keys"
+@send external values: t<'k, 'v> => Iterator.t<'v> = "values"
+@send external entries: t<'k, 'v> => Iterator.t<('k, 'v)> = "entries"
diff --git a/runtime/Map.resi b/runtime/Map.resi
new file mode 100644
index 0000000000..f1067a8abb
--- /dev/null
+++ b/runtime/Map.resi
@@ -0,0 +1,265 @@
+/***
+Bindings to the mutable JavaScript `Map`.
+
+See [`Map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) on MDN.
+*/
+
+/**
+Type representing an instance of `Map`.
+*/
+type t<'k, 'v> = Js.Map.t<'k, 'v>
+
+/**
+Creates a new, mutable JavaScript `Map`. A `Map` can have any values as both keys and values.
+
+See [`Map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) on MDN.
+
+
+
+## Examples
+```rescript
+`make()`
+// You can annotate the type of your map if you want to
+let myMap: Map.t<string, int> = Map.make()
+
+// Or you can let ReScript infer what's in your map
+let map = Map.make()
+map->Map.set("lang", "ReScript") // Inferred as Map.t<string, string>
+```
+
+## Alternatives
+A JavaScript `Map` is mutable. If you're looking for an immutable alternative, check out`Belt.Map`.
+*/
+@new
+external make: unit => t<'k, 'v> = "Map"
+
+/**
+Turns an array of key/value pairs into a Map.
+
+## Examples
+```rescript
+type languages = ReScript | JavaScript | TypeScript
+let languageRank = [(ReScript, 1), (JavaScript, 2), (TypeScript, 3)]
+
+let map = Map.fromArray(languageRank) // Map.t<languages, int>
+
+switch map->Map.get(ReScript) {
+| Some(1) => Console.log("Yay, ReScript is #1!")
+| _ => Console.log("Uh-oh, something is _terribly_ wrong with this program... abort.")
+}
+```
+*/
+@new
+external fromArray: array<('k, 'v)> => t<'k, 'v> = "Map"
+
+/**
+Turns an iterator in the shape of `('key, 'value)` into a `Map`.
+
+## Examples
+```rescript
+// Let's pretend we have an interator in the correct shape
+@val external someIterator: Iterator.t<(string, int)> = "someIterator"
+
+let map = Map.fromIterator(someIterator) // Map.t<string, int>
+```
+*/
+@new
+external fromIterator: Iterator.t<('k, 'v)> => t<'k, 'v> = "Map"
+
+/**
+Returns the size, the number of key/value pairs, of the map.
+
+## Examples
+```rescript
+let map = Map.make()
+
+map->Map.set("someKey", "someValue")
+
+let size = map->Map.size // 1
+```
+*/
+@get
+external size: t<'k, 'v> => int = "size"
+
+/**
+Clears all entries in the map.
+
+## Examples
+```rescript
+let map = Map.make()
+
+map->Map.set("someKey", "someValue")
+map->Map.size // 1
+
+map->Map.clear
+map->Map.size // 0
+```
+*/
+@send
+external clear: t<'k, 'v> => unit = "clear"
+
+/**
+Iterates through all values of the map.
+
+> Please note that this is *without the keys*, just the values. If you need the key as well, use `Map.forEachWithKey`.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+map->Map.set("someKey2", "someValue2")
+
+map->Map.forEach(value => {
+  Console.log(value)
+})
+```
+*/
+@send
+external forEach: (t<'k, 'v>, 'v => unit) => unit = "forEach"
+
+/**
+Iterates through all values of the map, including the key for each value.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+map->Map.set("someKey2", "someValue2")
+
+map->Map.forEachWithKey((value, key) => {
+  Console.log2(value, key)
+})
+```
+*/
+@send
+external forEachWithKey: (t<'k, 'v>, ('v, 'k) => unit) => unit = "forEach"
+
+/**
+Returns the value for a key, if a value exists at that key.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+
+switch map->Map.get("someKey") {
+| None => Console.log("Nope, didn't have it.")
+| Some(value) => Console.log2("Yay, had the value, and it's:", value)
+}
+```
+*/
+@send
+external get: (t<'k, 'v>, 'k) => option<'v> = "get"
+
+/**
+Checks whether the map has a specific key.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+
+switch map->Map.has("someKey") {
+| false => Console.log("Nope, didn't have it.")
+| true => Console.log("Yay, we have the value!")
+}
+```
+*/
+@send
+external has: (t<'k, 'v>, 'k) => bool = "has"
+
+/**
+Sets the provided `value` to the provided `key`.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+```
+*/
+@send
+external set: (t<'k, 'v>, 'k, 'v) => unit = "set"
+
+/**
+Deletes the provided `key` and its value from the map. Returns a `bool` for whether the key existed, and was deleted.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+let didDeleteKey = map->Map.delete("someKey")
+Console.log(didDeleteKey) // Logs `true` to the console, becuase the map had the key, so it was successfully deleted
+
+let didDeleteKey = map->Map.delete("someNonExistantKey")
+Console.log(didDeleteKey) // Logs `false` to the console, becuase the key did not exist
+```
+*/
+@send
+external delete: (t<'k, 'v>, 'k) => bool = "delete"
+
+/**
+Returns an iterator that holds all keys of the map.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+map->Map.set("anotherKey", "anotherValue")
+
+let keys = map->Map.keys
+
+// Logs the first key
+Console.log(Iterator.next(keys).value)
+
+// You can also turn the iterator into an array.
+// Remember that an iterator consumes values. We'll need a fresh keys iterator to get an array of all keys, since we consumed a value via `next` above already.
+Console.log(map->Map.keys->Iterator.toArray)
+```
+*/
+@send
+external keys: t<'k, 'v> => Iterator.t<'k> = "keys"
+
+/**
+Returns an iterator that holds all values of the map.
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+map->Map.set("anotherKey", "anotherValue")
+
+let values = map->Map.values
+
+// Logs the first value
+Console.log(Iterator.next(values).value)
+
+// You can also turn the iterator into an array.
+// Remember that an iterator consumes values. We'll need a fresh values iterator to get an array of all values, since we consumed a value via `next` above already.
+Console.log(map->Map.values->Iterator.toArray)
+```
+*/
+@send
+external values: t<'k, 'v> => Iterator.t<'v> = "values"
+
+/**
+Returns an iterator that holds all entries of the map.
+An entry is represented as a tuple of `('key, 'value)`,
+
+## Examples
+```rescript
+let map = Map.make()
+map->Map.set("someKey", "someValue")
+map->Map.set("anotherKey", "anotherValue")
+
+let entries = map->Map.entries
+
+// Logs the first value
+Console.log(Iterator.next(entries).value)
+
+// You can also turn the iterator into an array.
+// Remember that an iterator consumes entries. We'll need a fresh entries iterator to get an array of all entries, since we consumed a value via `next` above already.
+Console.log(map->Map.entries->Iterator.toArray)
+```
+*/
+@send
+external entries: t<'k, 'v> => Iterator.t<('k, 'v)> = "entries"
diff --git a/runtime/Math.res b/runtime/Math.res
new file mode 100644
index 0000000000..11d17501d1
--- /dev/null
+++ b/runtime/Math.res
@@ -0,0 +1,62 @@
+module Constants = {
+  @val external e: float = "Math.E"
+  @val external ln2: float = "Math.LN2"
+  @val external ln10: float = "Math.LN10"
+  @val external log2e: float = "Math.LOG2E"
+  @val external log10e: float = "Math.LOG10E"
+  @val external pi: float = "Math.PI"
+  @val external sqrt1_2: float = "Math.SQRT1_2"
+  @val external sqrt2: float = "Math.SQRT2"
+}
+
+@val external abs: float => float = "Math.abs"
+@val external acos: float => float = "Math.acos"
+@val external acosh: float => float = "Math.acosh"
+@val external asin: float => float = "Math.asin"
+@val external asinh: float => float = "Math.asinh"
+@val external atan: float => float = "Math.atan"
+@val external atanh: float => float = "Math.atanh"
+@val external atan2: (~y: float, ~x: float) => float = "Math.atan2"
+@val external cbrt: float => float = "Math.cbrt"
+@val external ceil: float => float = "Math.ceil"
+@val external cos: float => float = "Math.cos"
+@val external cosh: float => float = "Math.cosh"
+@val external exp: float => float = "Math.exp"
+@val external expm1: float => float = "Math.expm1"
+@val external floor: float => float = "Math.floor"
+@val external fround: float => float = "Math.fround"
+@val external hypot: (float, float) => float = "Math.hypot"
+@variadic @val external hypotMany: array<float> => float = "Math.hypot"
+@val external log: float => float = "Math.log"
+@val external log1p: float => float = "Math.log1p"
+@val external log10: float => float = "Math.log10"
+@val external log2: float => float = "Math.log2"
+@val external min: (float, float) => float = "Math.min"
+@variadic @val external minMany: array<float> => float = "Math.min"
+@val external max: (float, float) => float = "Math.max"
+@variadic @val external maxMany: array<float> => float = "Math.max"
+@val external pow: (float, ~exp: float) => float = "Math.pow"
+@val external random: unit => float = "Math.random"
+@val external round: float => float = "Math.round"
+@val external sign: float => float = "Math.sign"
+@val external sin: float => float = "Math.sin"
+@val external sinh: float => float = "Math.sinh"
+@val external sqrt: float => float = "Math.sqrt"
+@val external tan: float => float = "Math.tan"
+@val external tanh: float => float = "Math.tanh"
+@val external trunc: float => float = "Math.trunc"
+
+module Int = {
+  @val external abs: int => int = "Math.abs"
+  @val external clz32: int => int = "Math.clz32"
+  @val external imul: (int, int) => int = "Math.imul"
+  @val external min: (int, int) => int = "Math.min"
+  @variadic @val external minMany: array<int> => int = "Math.min"
+  @val external max: (int, int) => int = "Math.max"
+  @variadic @val external maxMany: array<int> => int = "Math.max"
+  @val external pow: (int, ~exp: int) => int = "Math.pow"
+  @val external sign: int => int = "Math.sign"
+  let floor: float => int = f => f->floor->Float.toInt
+  let ceil: float => int = f => f->ceil->Float.toInt
+  let random: (int, int) => int = (min, max) => floor(random() *. Int.toFloat(max - min)) + min
+}
diff --git a/runtime/Math.resi b/runtime/Math.resi
new file mode 100644
index 0000000000..ef146f9bcb
--- /dev/null
+++ b/runtime/Math.resi
@@ -0,0 +1,892 @@
+/* Copyright (C) 2015-2016 Bloomberg Finance L.P.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/***
+Functions for interacting with JavaScript Math.
+See: [`Math`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math).
+*/
+
+/**
+Mathematical Constants
+*/
+module Constants: {
+  /**
+  `Math.Constants.e` returns Euler's number, ≈ 2.718281828459045.
+  See [`Math.E`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/E) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Constants.e
+  ```
+  */
+  @val
+  external e: float = "Math.E"
+
+  /**
+  `Math.Constants.ln2` returns Natural logarithm of 2, ≈ 0.6931471805599453.
+  See [`Math.LN2`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/LN2) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Constants.ln2
+  ```
+  */
+  @val
+  external ln2: float = "Math.LN2"
+
+  /**
+  `Math.Constants.ln10` returns Natural logarithm of 10, ≈ 2.302585092994046.
+  See [`Math.LN10`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/LN10) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Constants.ln10
+  ```
+  */
+  @val
+  external ln10: float = "Math.LN10"
+
+  /**
+  `Math.Constants.log2e` returns Base 2 logarithm of E, ≈ 1.4426950408889634.
+  See [`Math.LOG2E`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/LOG2E) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Constants.log2e
+  ```
+  */
+  @val
+  external log2e: float = "Math.LOG2E"
+
+  /**
+  `Math.Constants.log10e` returns Base 10 logarithm of E, ≈ 0.4342944819032518.
+  See [`Math.LOG10E`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/LOG10E) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Constants.log10e
+  ```
+  */
+  @val
+  external log10e: float = "Math.LOG10E"
+  /**
+  `Math.Constants.pi` returns Pi - ratio of the circumference to the diameter
+  of a circle, ≈ 3.141592653589793.
+  See [`Math.PI`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/PI) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Constants.pi
+  ```
+  */
+  @val
+  external pi: float = "Math.PI"
+  /**
+  `Math.Constants.sqrt1_2` returns Square root of 1/2, ≈ 0.7071067811865476.
+  See [`Math.SQRT1_2`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/SQRT1_2) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Constants.sqrt1_2
+  ```
+  */
+  @val
+  external sqrt1_2: float = "Math.SQRT1_2"
+  /**
+  `Math.Constants.e` returns Absolute value for integer argument.
+  See [`Math.abs`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/abs) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Constants.sqrt2
+  ```
+  */
+  @val
+  external sqrt2: float = "Math.SQRT2"
+}
+
+/**
+Provide Math utilities for `int`
+*/
+module Int: {
+  /**
+  `abs(v)` returns absolute value of `v`.
+  See [`Math.abs`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/abs) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.abs(-2) // 2
+  Math.Int.abs(3) // 3
+  ```
+  */
+  @val
+  external abs: int => int = "Math.abs"
+
+  /**
+  `clz32(v)` returns the number of leading zero bits of the argument's 32 bit
+  int representation.
+  See [`Math.clz32`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/clz32) on MDN.
+
+  ## Examples
+
+  ```rescript
+  // 00000000000000000000000000000001
+  Math.Int.clz32(1) // 31
+  // 00000000000000000000000000000100
+  Math.Int.clz32(4) // 29
+  ```
+  */
+  @val
+  external clz32: int => int = "Math.clz32"
+
+  /**
+  `imul(a, b)` returns 32-bit integer multiplication. Use this only when you
+  need to optimize performance of multiplication of numbers stored as 32-bit
+  integers.
+  See [`Math.imul`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/imul) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.imul(3, 4) // 12
+  Math.Int.imul(-5, 12) // 60
+  ```
+  */
+  @val
+  external imul: (int, int) => int = "Math.imul"
+
+  /**
+  `min(a, b)` returns the minimum of its two integer arguments.
+  See [`Math.min`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/min) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.min(1, 2) // 1
+  Math.Int.min(-1, -2) // -2
+  ```
+  */
+  @val
+  external min: (int, int) => int = "Math.min"
+
+  /**
+  `minMany(arr)` returns the minimum of the integers in the given array `arr`.
+  Returns `Infinity` if `arr` is empty.
+  See [`Math.min`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/min) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.minMany([1, 2]) // 1
+  Math.Int.minMany([-1, -2]) // -2
+  Math.Int.minMany([])->Int.toFloat->Float.isFinite // false
+  ```
+  */
+  @variadic
+  @val
+  external minMany: array<int> => int = "Math.min"
+
+  /**
+  `max(a, b)` returns the maximum of its two integer arguments.
+  See [`Math.max`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/max) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.max(1, 2) // 2
+  Math.Int.max(-1, -2) // -1
+  ```
+  */
+  @val
+  external max: (int, int) => int = "Math.max"
+
+  /**
+  `maxMany(arr)` returns the maximum of the integers in the given array `arr`.
+  Returns `Infinity` if `arr` is empty.
+  See [`Math.max`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/max) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.maxMany([1, 2]) // 2
+  Math.Int.maxMany([-1, -2]) // -1
+  Math.Int.maxMany([])->Int.toFloat->Float.isFinite // false
+  ```
+  */
+  @variadic
+  @val
+  external maxMany: array<int> => int = "Math.max"
+
+  /**
+  `pow(a, ~exp)` raises the given base `a` to the given exponent `exp`.
+  See [`Math.pow`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/pow) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.pow(2, ~exp=4) // 16
+  Math.Int.pow(3, ~exp=4) // 81
+  ```
+  */
+  @val
+  external pow: (int, ~exp: int) => int = "Math.pow"
+
+  /**
+  `sign(v)` returns the sign of its integer argument: `-1` if negative, `0` if
+  zero, `1` if positive.
+  See [`Math.sign`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sign) on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.sign(3) // 1
+  Math.Int.sign(-3) // 1
+  Math.Int.sign(0) // 0
+  ```
+  */
+  @val
+  external sign: int => int = "Math.sign"
+
+  /**
+  floor(v) returns the largest `int` less than or equal to the argument; 
+  See [`Math.floor`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor)
+  on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.floor(3.7) == 3
+  Math.Int.floor(3.0) == 3
+  Math.Int.floor(-3.1) == -4
+  ```
+  */
+  let floor: float => int
+
+  /**
+  ceil(v) returns the smallest `int` greater than or equal to the argument;
+  See [`Math.floor`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor)
+  on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.ceil(3.7) == 4
+  Math.Int.ceil(3.0) == 3
+  Math.Int.ceil(-3.1) == -3
+  ```
+  */
+  let ceil: float => int
+
+  /**
+  `random(minVal, maxVal)` returns a random integer number in the half-closed interval [minVal, maxVal).
+   See [`Math.random`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random)
+  on MDN.
+
+  ## Examples
+
+  ```rescript
+  Math.Int.random(2, 5) == 4
+  Math.Int.random(505, 2000) == 1276
+  Math.Int.random(-7, -2) == -4
+  ```
+  */
+  let random: (int, int) => int
+}
+
+/**
+`abs(v)` returns absolute value of `v`.
+See [`Math.abs`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/abs) on MDN.
+
+## Examples
+
+```rescript
+Math.abs(-2.0) // 2.0
+Math.abs(3.0) // 3.0
+```
+  */
+@val
+external abs: float => float = "Math.abs"
+
+/**
+`acos(v)` returns arccosine (in radians) of argument `v`, returns `NaN` if the
+argument is outside the range [-1.0, 1.0].
+See [`Math.acos`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/acos) on MDN.
+
+## Examples
+
+```rescript
+Math.acos(-1.0) // 3.141592653589793
+Math.acos(-3.0)->Float.isNaN // true
+```
+*/
+@val
+external acos: float => float = "Math.acos"
+
+/**
+`acosh(v)` returns the inverse hyperbolic arccosine (in radians) of argument `v`,
+returns `NaN` if the argument is less than `1.0`.
+See [`Math.acosh`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/acosh) on MDN.
+
+## Examples
+
+```rescript
+Math.acosh(1.0) // 0.0
+Math.acosh(0.5)->Float.isNaN // true
+```
+*/
+@val
+external acosh: float => float = "Math.acosh"
+
+/**
+`asin(v)` returns the inverse sine (in radians) of argument `v`, returns `NaN`
+if the argument `v` is outside the range [-1.0, 1.0].
+See [`Math.asin`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/asin) on MDN.
+
+## Examples
+
+```rescript
+Math.asin(-1.0) // -1.5707963267948966
+Math.asin(-2.0)->Float.isNaN // true
+```
+*/
+@val
+external asin: float => float = "Math.asin"
+
+/**
+`asinh(v)` returns the inverse hyperbolic sine of argument `v`.
+See [`Math.asinh`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/asinh) on MDN.
+
+## Examples
+
+```rescript
+Math.asinh(-1.0) // -0.881373587019543
+Math.asinh(-0.0) // -0.0
+```
+*/
+@val
+external asinh: float => float = "Math.asinh"
+
+/**
+`atan(v)` returns the inverse tangent (in radians) of argument `v`.
+See [`Math.atan`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/atan) on MDN.
+
+## Examples
+
+```rescript
+Math.atan(-0.0) // -0.0
+Math.atan(0.0) // 0.0
+Math.atan(1.0) // 0.7853981633974483
+```
+*/
+@val
+external atan: float => float = "Math.atan"
+
+/**
+`atanh(v)` returns the invert hyperbolic tangent of argument `v`. Returns `NaN`
+if the argument `v` is is outside the range [-1.0, 1.0] and `Infinity` if `v`
+is `-1.0` or `1.0`.
+See [`Math.atanh`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/atanh) on MDN.
+
+## Examples
+
+```rescript
+Math.atanh(-2.0)->Float.isNaN // true
+Math.atanh(-1.0)->Float.isFinite // false
+Math.atanh(-0.0) // -0.0
+Math.atanh(0.0) // 0.0
+Math.atanh(0.5) // 0.5493061443340548
+```
+*/
+@val
+external atanh: float => float = "Math.atanh"
+
+/**
+`atan2(~y, ~x)` returns the angle (in radians) of the quotient `y /. x`. It is
+also the angle between the *x*-axis and point (*x*, *y*).
+See [`Math.atan2`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/atan2) on MDN.
+
+## Examples
+
+```rescript
+Math.atan2(~y=0.0, ~x=10.0) == 0.0
+Math.atan2(~x=5.0, ~y=5.0) == Math.Constants.pi /. 4.0
+Math.atan2(~x=90.0, ~y=15.0) // 1.4056476493802699
+Math.atan2(~x=15.0, ~y=90.0) // 0.16514867741462683
+```
+*/
+@val
+external atan2: (~y: float, ~x: float) => float = "Math.atan2"
+
+/**
+`cbrt(v)` returns the cube root of argument `v`.
+See [`Math.cbrt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/cbrt) on MDN.
+
+## Examples
+
+```rescript
+Math.cbrt(-1.0) // -1.0
+Math.cbrt(-0.0) // -0.0
+Math.cbrt(0.0) // 0.0
+```
+*/
+@val
+external cbrt: float => float = "Math.cbrt"
+
+/**
+`ceil(v)` returns the smallest integral value greater than or equal to the
+argument `v`. The result is a `float` and is not restricted to the `int` data
+type range.
+See [`Math.ceil`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/ceil) on MDN.
+
+## Examples
+
+```rescript
+Math.ceil(3.1) == 4.0
+Math.ceil(3.0) == 3.0
+Math.ceil(-3.1) == -3.0
+Math.ceil(2_150_000_000.3) == 2_150_000_001.0
+```
+*/
+@val
+external ceil: float => float = "Math.ceil"
+
+/**
+`cos(v)` returns the cosine of argument `v`, which must be specified in radians.
+See [`Math.cos`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/cos) on MDN.
+
+## Examples
+
+```rescript
+Math.cos(-0.0) // 1.0
+Math.cos(0.0) // 1.0
+Math.cos(1.0) // 0.5403023058681398
+```
+*/
+@val
+external cos: float => float = "Math.cos"
+
+/**
+`cosh(v)` returns the hyperbolic cosine of argument `v`, which must be specified
+in radians.
+See [`Math.cosh`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/cosh) on MDN.
+
+## Examples
+
+```rescript
+Math.cosh(-1.0) // 1.5430806348152437
+Math.cosh(-0.0) // 1.0
+Math.cosh(0.0) // 1.0
+```
+*/
+@val
+external cosh: float => float = "Math.cosh"
+
+/**
+`exp(v)` returns natural exponentional, returns *e* (the base of natural logarithms)
+to the power of the given argument `v`.
+See [`Math.exp`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/exp) on MDN.
+
+## Examples
+
+```rescript
+Math.exp(-1.0) // 0.36787944117144233
+Math.exp(0.0) // 1.0
+```
+*/
+@val
+external exp: float => float = "Math.exp"
+
+/**
+`expm1(v)` returns *e* (the base of natural logarithms) to the power of the given
+argument `v` minus 1.
+See [`Math.expm1`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/expm1) on MDN.
+
+## Examples
+
+```rescript
+Math.expm1(-1.0) // -0.6321205588285577
+Math.expm1(-0.0) // -0
+```
+*/
+@val
+external expm1: float => float = "Math.expm1"
+
+/**
+`floor(v)` returns the largest integral value less than or equal to the argument
+`v`. The result is a `float` and is not restricted to the `int` data type range.
+See [`Math.floor`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor) on MDN.
+
+## Examples
+
+```rescript
+Math.floor(-45.95) // -46.0
+Math.floor(-45.05) // -46.0
+Math.floor(-0.0) // -0.0
+```
+*/
+@val
+external floor: float => float = "Math.floor"
+
+/**
+`fround(v)` returns the nearest single precision float.
+See [`Math.fround`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/fround) on MDN.
+
+## Examples
+
+```rescript
+Math.fround(5.5) == 5.5
+Math.fround(5.05) == 5.050000190734863
+```
+*/
+@val
+external fround: float => float = "Math.fround"
+
+/**
+`hypot(a, b)` returns the square root of the sum of squares of its two arguments
+(the Pythagorean formula).
+See [`Math.hypot`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/hypot) on MDN.
+
+## Examples
+
+```rescript
+Math.hypot(3.0, 4.0) // 5.0
+Math.hypot(3.0, 5.0) // 5.8309518948453
+```
+*/
+@val
+external hypot: (float, float) => float = "Math.hypot"
+
+/**
+`hypotMany(arr)` returns the square root of the sum of squares of the numbers in
+the array argument (generalized Pythagorean equation). Using an array allows you
+to have more than two items. If `arr` is an empty array then returns `0.0`.
+See [`Math.hypot`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/hypot) on MDN.
+
+## Examples
+
+```rescript
+Math.hypotMany([3.0, 4.0, 5.0]) // 7.0710678118654755
+Math.hypotMany([]) // 0.0
+```
+*/
+@variadic
+@val
+external hypotMany: array<float> => float = "Math.hypot"
+
+/**
+`log(v)` returns the natural logarithm of argument `v`, this is the number *x*
+such that `e^x` equals the argument. Returns `NaN` for negative arguments and
+`Infinity` for `0.0` or `-0.0`.
+See [`Math.log`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/log) on MDN.
+
+## Examples
+
+```rescript
+Math.log(-1.0)->Float.isNaN // true
+Math.log(-0.0)->Float.isFinite // false
+Math.log(0.0)->Float.isFinite // false
+Math.log(1.0) // 0
+```
+*/
+@val
+external log: float => float = "Math.log"
+
+/**
+`log1p(v)` returns the natural logarithm of one plus the argument `v`.
+Returns `NaN` for arguments less than `-1` and `Infinity` if `v` is `-1.0`.
+See [`Math.log1p`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/log1p) on MDN.
+
+## Examples
+
+```rescript
+Math.log1p(-2.0)->Float.isNaN // true
+Math.log1p(-1.0)->Float.isFinite // false
+Math.log1p(-0.0) // -0
+```
+*/
+@val
+external log1p: float => float = "Math.log1p"
+
+/**
+`log10(v)` returns the base 10 logarithm of argument `v`. Returns `NaN` for
+negative `v`. If `v` is `-0.0` or `0.0` returns `Infinity`.
+See [`Math.log10`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/log10) on MDN.
+
+## Examples
+
+```rescript
+Math.log10(-2.0)->Float.isNaN // true
+Math.log10(-0.0)->Float.isFinite // false
+Math.log10(0.0)->Float.isFinite // false
+Math.log10(1.0) // 0
+```
+*/
+@val
+external log10: float => float = "Math.log10"
+
+/**
+`log2(v)` returns the base 2 logarithm of argument `v`. Returns `NaN` for
+negative `v` and `Infinity` if `v` is `-0.0` or `0.0`.
+See [`Math.log2`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/log2) on MDN.
+
+## Examples
+
+```rescript
+Math.log2(-2.0)->Float.isNaN // true
+Math.log2(-0.0)->Float.isFinite // false
+Math.log2(0.0)->Float.isFinite // false
+Math.log2(1.0) // 0.0
+```
+*/
+@val
+external log2: float => float = "Math.log2"
+
+/**
+`min(a, b)` returns the minimum of its two float arguments.
+See [`Math.min`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/min) on MDN.
+
+## Examples
+
+```rescript
+Math.min(1.0, 2.0) // 1.0
+Math.min(-1.0, -2.0) // -2.0
+```
+*/
+@val
+external min: (float, float) => float = "Math.min"
+
+/**
+`minMany(arr)` returns the minimum of the float in the given array `arr`.
+Returns `Infinity` if `arr` is empty.
+See [`Math.min`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/min) on MDN.
+
+## Examples
+
+```rescript
+Math.minMany([1.0, 2.0]) // 1.0
+Math.minMany([-1.0, -2.0]) // -2.0
+Math.minMany([])->Float.isFinite // false
+```
+*/
+@variadic
+@val
+external minMany: array<float> => float = "Math.min"
+
+/**
+`max(a, b)` returns the maximum of its two float arguments.
+See [`Math.max`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/max) on MDN.
+
+## Examples
+
+```rescript
+Math.max(1.0, 2.0) // 2.0
+Math.max(-1.0, -2.0) // -1.0
+```
+*/
+@val
+external max: (float, float) => float = "Math.max"
+
+/**
+`maxMany(arr)` returns the maximum of the float in the given array `arr`.
+Returns `Infinity` if `arr` is empty.
+See [`Math.max`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/max) on MDN.
+
+## Examples
+
+```rescript
+Math.maxMany([1.0, 2.0]) // 2.0
+Math.maxMany([-1.0, -2.0]) // -1.0
+Math.maxMany([])->Float.isFinite // false
+```
+*/
+@variadic
+@val
+external maxMany: array<float> => float = "Math.max"
+
+/**
+`pow(a, ~exp)` raises the given base `a` to the given exponent `exp`.
+See [`Math.pow`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/pow) on MDN.
+
+## Examples
+
+```rescript
+Math.pow(2.0, ~exp=4.0) // 16.0
+Math.pow(3.0, ~exp=4.0) // 81.0
+```
+*/
+@val
+external pow: (float, ~exp: float) => float = "Math.pow"
+
+/**
+`random()` returns a random number in the half-closed interval [0,1].
+See [`Math.random`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random) on MDN.
+
+## Examples
+
+```rescript
+Math.random()
+```
+*/
+@val
+external random: unit => float = "Math.random"
+
+/**
+`round(v)` returns then value of `v` rounded to nearest integral value
+(expressed as a float). If the fractional portion of the argument `v` is greater
+than `0.5`, the argument `v` is rounded to the float with the next higher
+absolute value.
+See [`Math.round`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/round) on MDN.
+
+## Examples
+
+```rescript
+Math.round(-20.5) // -20.0
+Math.round(-0.1) // -0.0
+Math.round(0.0) // 0.0
+Math.round(-0.0) // -0.0
+```
+*/
+@val
+external round: float => float = "Math.round"
+
+/**
+`sign(v)` returns the sign of its foat argument: `-1` if negative, `0` if
+zero, `1` if positive.
+See [`Math.sign`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sign) on MDN.
+
+## Examples
+
+```rescript
+Math.sign(3.0) // 1.0
+Math.sign(-3.0) // 1.0
+Math.sign(0.0) // 0.0
+```
+*/
+@val
+external sign: float => float = "Math.sign"
+
+/**
+`sin(v)` returns the sine of argument `v`, which must be specified in radians.
+See [`Math.sin`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sin) on MDN.
+
+## Examples
+
+```rescript
+Math.sin(-0.0) // -0.0
+Math.sin(0.0) // 0.0
+Math.sin(1.0) // 0.8414709848078965
+```
+*/
+@val
+external sin: float => float = "Math.sin"
+
+/**
+`sinh(v)` returns then hyperbolic sine of argument `v`, which must be specified
+in radians.
+See [`Math.sinh`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sinh) on MDN.
+
+## Examples
+
+```rescript
+Math.sinh(-0.0) // -0.0
+Math.sinh(0.0) // 0.0
+Math.sinh(1.0) // 1.1752011936438014
+```
+*/
+@val
+external sinh: float => float = "Math.sinh"
+
+/**
+`sqrt(v)` returns the square root of `v`. If `v` is negative returns `NaN`.
+See [`Math.sqrt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sqrt) on MDN.
+
+## Examples
+
+```rescript
+Math.sqrt(-1.0)->Float.isNaN // true
+Math.sqrt(-0.0) // -0.0
+Math.sqrt(0.0) // 0.0
+Math.sqrt(1.0) // 1.0
+Math.sqrt(9.0) // 3.0
+```
+*/
+@val
+external sqrt: float => float = "Math.sqrt"
+
+/**
+`tan(v)` returns the tangent of argument `v`, which must be specified in
+radians. Returns `NaN` if `v` is positive `Infinity` or negative `Infinity`.
+See [`Math.tan`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/tan) on MDN.
+
+## Examples
+
+```rescript
+Math.tan(-0.0) // -0.0
+Math.tan(0.0) // 0.0
+Math.tan(1.0) // 1.5574077246549023
+```
+*/
+@val
+external tan: float => float = "Math.tan"
+
+/**
+`tanh(v)` returns the hyperbolic tangent of argument `v`, which must be
+specified in radians.
+See [`Math.tanh`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/tanh) on MDN.
+
+## Examples
+
+```rescript
+Math.tanh(-0.0) // -0.0
+Math.tanh(0.0) // 0.0
+Math.tanh(1.0) // 0.7615941559557649
+```
+*/
+@val
+external tanh: float => float = "Math.tanh"
+
+/**
+`trunc(v)` truncates the argument `v`, i.e., removes fractional digits.
+See [`Math.trunc`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/trunc) on MDN.
+
+## Examples
+
+```rescript
+Math.trunc(0.123) // 0.0
+Math.trunc(1.999) // 1.0
+Math.trunc(13.37) // 13.0
+Math.trunc(42.84) // 42.0
+```
+*/
+@val
+external trunc: float => float = "Math.trunc"
diff --git a/runtime/Null.res b/runtime/Null.res
new file mode 100644
index 0000000000..2bbb9a2ab5
--- /dev/null
+++ b/runtime/Null.res
@@ -0,0 +1,64 @@
+@unboxed
+type t<'a> = Js.Null.t<'a> =
+  | Value('a)
+  | @as(null) Null
+
+external asNullable: t<'a> => Nullable.t<'a> = "%identity"
+
+external null: t<'a> = "#null"
+
+external make: 'a => t<'a> = "%identity"
+
+external toOption: t<'a> => option<'a> = "#null_to_opt"
+
+let fromOption: option<'a> => t<'a> = option =>
+  switch option {
+  | Some(x) => make(x)
+  | None => null
+  }
+
+let equal = (a, b, eq) => Option.equal(a->toOption, b->toOption, eq)
+
+let compare = (a, b, cmp) => Option.compare(a->toOption, b->toOption, cmp)
+
+let getOr = (value, default) =>
+  switch value->toOption {
+  | Some(x) => x
+  | None => default
+  }
+
+let getWithDefault = getOr
+
+let getExn: t<'a> => 'a = value =>
+  switch value->toOption {
+  | Some(x) => x
+  | None => raise(Invalid_argument("Null.getExn: value is null"))
+  }
+
+external getUnsafe: t<'a> => 'a = "%identity"
+
+let forEach = (value, f) =>
+  switch value->toOption {
+  | Some(x) => f(x)
+  | None => ()
+  }
+
+let map = (value, f) =>
+  switch value->toOption {
+  | Some(x) => make(f(x))
+  | None => null
+  }
+
+let mapOr = (value, default, f) =>
+  switch value->toOption {
+  | Some(x) => f(x)
+  | None => default
+  }
+
+let mapWithDefault = mapOr
+
+let flatMap = (value, f) =>
+  switch value->toOption {
+  | Some(x) => f(x)
+  | None => null
+  }
diff --git a/runtime/Null.resi b/runtime/Null.resi
new file mode 100644
index 0000000000..7d3f6a22fc
--- /dev/null
+++ b/runtime/Null.resi
@@ -0,0 +1,198 @@
+/***
+Functions for handling values that could be `null`.
+
+If you also need to cover `undefined`, check out `Nullable` instead.
+*/
+
+/**
+A type representing a value that can be either `'a` or `null`.
+*/
+@unboxed
+type t<'a> = Js.Null.t<'a> =
+  | Value('a)
+  | @as(null) Null
+
+/**
+Converts a `Null.t` into a `Nullable.t`.
+
+## Examples
+```rescript
+let nullValue = Null.make("Hello")
+let asNullable = nullValue->Null.asNullable // Nullable.t<string>
+```
+*/
+external asNullable: t<'a> => Nullable.t<'a> = "%identity"
+
+/**
+The value `null`.
+
+See [`null`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/null) on MDN.
+
+## Examples
+```rescript
+Console.log(null) // Logs `null` to the console.
+```
+*/
+external null: t<'a> = "#null"
+
+/**
+Creates a new `Null.t` from the provided value.
+This means the compiler will enforce null checks for the new value.
+
+## Examples
+```rescript
+let myStr = "Hello"
+let asNullValue = myStr->Null.make // The compiler now thinks this can be `string` or `null`.
+```
+*/
+external make: 'a => t<'a> = "%identity"
+
+let equal: (t<'a>, t<'b>, ('a, 'b) => bool) => bool
+
+let compare: (t<'a>, t<'b>, ('a, 'b) => Ordering.t) => Ordering.t
+
+/**
+Converts a nullable value into an option, so it can be pattern matched on.
+Will convert `null` to `None`, and a present value to `Some(value)`.
+
+## Examples
+```rescript
+let nullStr = Null.make("Hello")
+
+switch nullStr->Null.toOption {
+| Some(str) => Console.log2("Got string:", str)
+| None => Console.log("Didn't have a value.")
+}
+```
+*/
+external toOption: t<'a> => option<'a> = "#null_to_opt"
+
+/**
+Turns an `option` into a `Null.t`. `None` will be converted to `null`.
+
+## Examples
+```rescript
+let optString: option<string> = None
+let asNull = optString->Null.fromOption // Null.t<string>
+Console.log(asNull == Null.null) // Logs `true` to the console.
+```
+*/
+let fromOption: option<'a> => t<'a>
+
+/**
+`getOr(value, default)` returns `value` if not `null`, otherwise return
+`default`.
+
+## Examples
+
+```rescript
+Null.getOr(Null.null, "Banana") // Banana
+Null.getOr(Null.make("Apple"), "Banana") // Apple
+
+let greet = (firstName: option<string>) =>
+  "Greetings " ++ firstName->Option.getOr("Anonymous")
+
+Null.make("Jane")->Null.toOption->greet // "Greetings Jane"
+Null.null->Null.toOption->greet // "Greetings Anonymous"
+```
+*/
+let getOr: (t<'a>, 'a) => 'a
+
+@deprecated("Use getOr instead")
+let getWithDefault: (t<'a>, 'a) => 'a
+
+/**
+`getExn(value)` raises an exception if `null`, otherwise returns the value.
+
+```rescript
+Null.getExn(Null.make(3)) // 3
+Null.getExn(Null.null) /* Raises an Error */
+```
+
+## Exceptions
+
+- Raises `Invalid_argument` if `value` is `null`,
+*/
+let getExn: t<'a> => 'a
+
+/**
+`getUnsafe(value)` returns `value`.
+
+## Examples
+
+```rescript
+Null.getUnsafe(Null.make(3)) == 3
+Null.getUnsafe(Null.null) // Raises an error
+```
+
+## Important
+
+- This is an unsafe operation, it assumes `value` is not `null`.
+*/
+external getUnsafe: t<'a> => 'a = "%identity"
+
+/**
+`forEach(value, f)` call `f` on `value`. if `value` is not `null`, then if calls
+`f`, otherwise returns `unit`.
+
+## Examples
+
+```rescript
+Null.forEach(Null.make("thing"), x => Console.log(x)) // logs "thing"
+Null.forEach(Null.null, x => Console.log(x)) // logs nothing
+```
+*/
+let forEach: (t<'a>, 'a => unit) => unit
+
+/**
+`map(value, f)` returns `f(value)` if `value` is not `null`, otherwise returns
+`value` unchanged.
+
+## Examples
+
+```rescript
+Null.map(Null.make(3), x => x * x) // Null.make(9)
+Null.map(Null.null, x => x * x) // null
+```
+*/
+let map: (t<'a>, 'a => 'b) => t<'b>
+
+/**
+`mapOr(value, default, f)` returns `f(value)` if `value` is not `null`,
+otherwise returns `default`.
+
+## Examples
+
+```rescript
+let someValue = Null.make(3)
+someValue->Null.mapOr(0, x => x + 5) // 8
+
+let noneValue = Null.null
+noneValue->Null.mapOr(0, x => x + 5) // 0
+```
+*/
+let mapOr: (t<'a>, 'b, 'a => 'b) => 'b
+
+@deprecated("Use mapOr instead")
+let mapWithDefault: (t<'a>, 'b, 'a => 'b) => 'b
+
+/**
+`flatMap(value, f)` returns `f(value)` if `value` is not `null`, otherwise
+returns `value` unchanged.
+
+## Examples
+
+```rescript
+let addIfAboveOne = value =>
+  if (value > 1) {
+    Null.make(value + 1)
+  } else {
+    Null.null
+  }
+
+Null.flatMap(Null.make(2), addIfAboveOne) // Null.make(3)
+Null.flatMap(Null.make(-4), addIfAboveOne) // null
+Null.flatMap(Null.null, addIfAboveOne) // null
+```
+*/
+let flatMap: (t<'a>, 'a => t<'b>) => t<'b>
diff --git a/runtime/Nullable.res b/runtime/Nullable.res
new file mode 100644
index 0000000000..aa08bcb68b
--- /dev/null
+++ b/runtime/Nullable.res
@@ -0,0 +1,67 @@
+@unboxed
+type t<'a> = Js.Nullable.t<'a> =
+  | Value('a)
+  | @as(null) Null
+  | @as(undefined) Undefined
+
+external null: t<'a> = "#null"
+
+external undefined: t<'a> = "#undefined"
+
+external isNullable: t<'a> => bool = "#is_nullable"
+
+external make: 'a => t<'a> = "%identity"
+
+external toOption: t<'a> => option<'a> = "#nullable_to_opt"
+
+let fromOption: option<'a> => t<'a> = option =>
+  switch option {
+  | Some(x) => make(x)
+  | None => undefined
+  }
+
+let equal = (a, b, eq) => Option.equal(a->toOption, b->toOption, eq)
+
+let compare = (a, b, cmp) => Option.compare(a->toOption, b->toOption, cmp)
+
+let getOr = (value, default) =>
+  switch value->toOption {
+  | Some(x) => x
+  | None => default
+  }
+
+let getWithDefault = getOr
+
+let getExn: t<'a> => 'a = value =>
+  switch value->toOption {
+  | Some(x) => x
+  | None => raise(Invalid_argument("Nullable.getExn: value is null or undefined"))
+  }
+
+external getUnsafe: t<'a> => 'a = "%identity"
+
+let forEach = (value, f) =>
+  switch value->toOption {
+  | Some(x) => f(x)
+  | None => ()
+  }
+
+let map = (value, f) =>
+  switch value->toOption {
+  | Some(x) => make(f(x))
+  | None => Obj.magic(value)
+  }
+
+let mapOr = (value, default, f) =>
+  switch value->toOption {
+  | Some(x) => f(x)
+  | None => default
+  }
+
+let mapWithDefault = mapOr
+
+let flatMap = (value, f) =>
+  switch value->toOption {
+  | Some(x) => f(x)
+  | None => Obj.magic(value)
+  }
diff --git a/runtime/Nullable.resi b/runtime/Nullable.resi
new file mode 100644
index 0000000000..30d92195e6
--- /dev/null
+++ b/runtime/Nullable.resi
@@ -0,0 +1,231 @@
+/***
+Functions for handling nullable values.
+
+Primarily useful when interoping with JavaScript when you don't know whether you'll get a value, `null` or `undefined`.
+*/
+
+/**
+Type representing a nullable value.
+A nullable value can be the value `'a`, `null` or `undefined`.
+*/
+@unboxed
+type t<'a> = Js.Nullable.t<'a> =
+  | Value('a)
+  | @as(null) Null
+  | @as(undefined) Undefined
+
+/**
+The value `null`.
+
+See [`null`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/null) on MDN.
+
+## Examples
+```rescript
+Console.log(Nullable.null) // Logs `null` to the console.
+```
+*/
+external null: t<'a> = "#null"
+
+/**
+The value `undefined`.
+
+See [`undefined`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/undefined) on MDN.
+
+## Examples
+```rescript
+Console.log(undefined) // Logs `undefined` to the console.
+```
+*/
+external undefined: t<'a> = "#undefined"
+
+/**
+`isNullable(a)` returns `true` if `a` is null or undefined, `false` otherwise.
+
+## Examples
+
+```rescript
+let myStr = "Hello"
+let asNullable = myStr->Nullable.make
+
+// Can't do the below because we're now forced to check for nullability
+// myStr == asNullable
+
+// Check if asNullable is not null or undefined
+switch asNullable->Nullable.isNullable {
+| true => assert(false)
+| false => assert(true)
+}
+```
+*/
+external isNullable: t<'a> => bool = "#is_nullable"
+
+/**
+Creates a new nullable value from the provided value.
+This means the compiler will enforce null checks for the new value.
+
+## Examples
+```rescript
+let myStr = "Hello"
+let asNullable = myStr->Nullable.make
+
+// Can't do the below because we're now forced to check for nullability
+// myStr == asNullable
+
+// Need to do this
+switch asNullable->Nullable.toOption {
+| Some(value) if value == myStr => Console.log("Yay, values matched!")
+| _ => Console.log("Values did not match.")
+}
+```
+*/
+external make: 'a => t<'a> = "%identity"
+
+let equal: (t<'a>, t<'b>, ('a, 'b) => bool) => bool
+
+let compare: (t<'a>, t<'b>, ('a, 'b) => Ordering.t) => Ordering.t
+
+/**
+Converts a nullable value into an option, so it can be pattern matched on.
+Will convert both `null` and `undefined` to `None`, and a present value to `Some(value)`.
+
+## Examples
+```rescript
+let nullableString = Nullable.make("Hello")
+
+switch nullableString->Nullable.toOption {
+| Some(str) => Console.log2("Got string:", str)
+| None => Console.log("Didn't have a value.")
+}
+```
+*/
+external toOption: t<'a> => option<'a> = "#nullable_to_opt"
+
+/**
+Turns an `option` into a `Nullable.t`.
+
+## Examples
+```rescript
+let optString = Some("Hello")
+let asNullable = optString->Nullable.fromOption // Nullable.t<string>
+```
+*/
+let fromOption: option<'a> => t<'a>
+
+/**
+`getOr(value, default)` returns `value` if not `null` or `undefined`,
+otherwise return `default`.
+
+## Examples
+
+```rescript
+Nullable.getOr(Nullable.null, "Banana") // Banana
+Nullable.getOr(Nullable.make("Apple"), "Banana") // Apple
+
+let greet = (firstName: option<string>) =>
+  "Greetings " ++ firstName->Option.getOr("Anonymous")
+
+Nullable.make("Jane")->Nullable.toOption->greet // "Greetings Jane"
+Nullable.null->Nullable.toOption->greet // "Greetings Anonymous"
+```
+*/
+let getOr: (t<'a>, 'a) => 'a
+
+@deprecated("Use getOr instead")
+let getWithDefault: (t<'a>, 'a) => 'a
+
+/**
+`getExn(value)` raises an exception if `null` or `undefined`, otherwise returns the value.
+
+```rescript
+Nullable.getExn(Nullable.make(3)) // 3
+Nullable.getExn(Nullable.null) /* Raises an Error */
+```
+
+## Exceptions
+
+- Raises `Invalid_argument` if `value` is `null` or `undefined`
+*/
+let getExn: t<'a> => 'a
+
+/**
+`getUnsafe(value)` returns `value`.
+
+## Examples
+
+```rescript
+Nullable.getUnsafe(Nullable.make(3)) == 3
+Nullable.getUnsafe(Nullable.null) // Raises an error
+```
+
+## Important
+
+- This is an unsafe operation, it assumes `value` is not `null` or `undefined`.
+*/
+external getUnsafe: t<'a> => 'a = "%identity"
+
+/**
+`forEach(value, f)` call `f` on `value`. if `value` is not `null` or `undefined`, 
+then if calls `f`, otherwise returns `unit`.
+
+## Examples
+
+```rescript
+Nullable.forEach(Nullable.make("thing"), x => Console.log(x)) // logs "thing"
+Nullable.forEach(Nullable.null, x => Console.log(x)) // returns ()
+Nullable.forEach(undefined, x => Console.log(x)) // returns ()
+```
+*/
+let forEach: (t<'a>, 'a => unit) => unit
+
+/**
+`map(value, f)` returns `f(value)` if `value` is not `null` or `undefined`,
+otherwise returns `value` unchanged.
+
+## Examples
+
+```rescript
+Nullable.map(Nullable.make(3), x => x * x) // Nullable.make(9)
+Nullable.map(undefined, x => x * x) // undefined
+```
+*/
+let map: (t<'a>, 'a => 'b) => t<'b>
+
+/**
+`mapOr(value, default, f)` returns `f(value)` if `value` is not `null`
+or `undefined`, otherwise returns `default`.
+
+## Examples
+
+```rescript
+let someValue = Nullable.make(3)
+someValue->Nullable.mapOr(0, x => x + 5) // 8
+
+let noneValue = Nullable.null
+noneValue->Nullable.mapOr(0, x => x + 5) // 0
+```
+*/
+let mapOr: (t<'a>, 'b, 'a => 'b) => 'b
+
+@deprecated("Use mapOr instead")
+let mapWithDefault: (t<'a>, 'b, 'a => 'b) => 'b
+
+/**
+`flatMap(value, f)` returns `f(value)` if `value` is not `null` or `undefined`,
+otherwise returns `value` unchanged.
+
+## Examples
+
+```rescript
+let addIfAboveOne = value =>
+  if (value > 1) {
+    Nullable.make(value + 1)
+  } else {
+    Nullable.null
+  }
+
+Nullable.flatMap(Nullable.make(2), addIfAboveOne) // Nullable.make(3)
+Nullable.flatMap(Nullable.make(-4), addIfAboveOne) // undefined
+Nullable.flatMap(Nullable.null, addIfAboveOne) // undefined
+```
+*/
+let flatMap: (t<'a>, 'a => t<'b>) => t<'b>
diff --git a/runtime/Object.res b/runtime/Object.res
new file mode 100644
index 0000000000..434621df86
--- /dev/null
+++ b/runtime/Object.res
@@ -0,0 +1,281 @@
+/**
+`make` create a new object that inherits the properties and methods from the standard built-in Object, such as `toString`. See [Object on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object)
+
+## Examples
+
+```rescript
+let x = Object.make()
+x->Object.keysToArray->Array.length // 0
+x->Object.get("toString")->Option.isSome // true
+```
+*/
+@obj
+external make: unit => {..} = ""
+
+/**
+`is` determines if two objects are identical in all contexts. Objects, arrays, records, and other non-primitives are only identical if they reference the **exact** same object in memory. Primitives like ints, floats, and strings are identical if they have the same value. `+0` and `-0` are distinct. NaN is equal to itself. See [Object.is on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is)
+
+In most scenarios use `==` or `===` or the custom `equals` function (if provided) for the type.
+
+## Examples
+
+```rescript
+Object.is(25, 13) // false
+Object.is("abc", "abc") // true
+Object.is(undefined, undefined) // true
+Object.is(undefined, null) // false
+Object.is(-0.0, 0.0) // false
+Object.is(list{1, 2}, list{1, 2}) // false
+
+Object.is([1, 2, 3], [1, 2, 3]) // false
+[1, 2, 3] == [1, 2, 3] // true
+[1, 2, 3] === [1, 2, 3] // false
+
+let fruit = {"name": "Apple" }
+Object.is(fruit, fruit) // true
+Object.is(fruit, {"name": "Apple" }) // false
+fruit == {"name": "Apple" } // true
+fruit === {"name": "Apple" } // false
+```
+*/
+@val
+external is: ('a, 'a) => bool = "Object.is"
+
+/**
+`create` creates a new object, using an existing object as the prototype of the new object. See [Object.create on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/create)
+
+**Note:** ReScript provides [first-class support for immutable objects](https://rescript-lang.org/docs/manual/latest/object) and [records](https://rescript-lang.org/docs/manual/latest/record). This is often safer and more convenient than using `create` and other functions in this module.
+
+## Examples
+
+```rescript
+let x = {"fruit": "banana"}
+let y = Object.create(x)
+y->Object.get("fruit") // Some("banana")
+```
+*/
+@val
+external create: {..} => {..} = "Object.create"
+
+@val external createWithProperties: ({..}, {..}) => {..} = "Object.create"
+
+@val external createWithNull: (@as(json`null`) _, unit) => {..} = "Object.create"
+
+@val external createWithNullAndProperties: (@as(json`null`) _, {..}) => {..} = "Object.create"
+
+/**
+`assign(target, source)` copies enumerable own properties from the source to the target, overwriting properties with the same name. It returns the modified target object. A deep clone is not created; properties are copied by reference.
+
+**Warning:** ReScript provides compile-time support for type-safe access to JavaScript objects. This eliminates common errors such as accessing properties that do not exist, or using a property of type x as if it were a y. Using `assign` can bypass these safety checks and lead to run-time errors (if you are not careful). ReScript provides [first-class support for immutable objects](https://rescript-lang.org/docs/manual/latest/object) and [records](https://rescript-lang.org/docs/manual/latest/record). This is often safer and more convenient than using `assign` and other functions in this module.
+
+See [Object.assign on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign) or [ECMAScript Language Specification](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.assign).
+
+## Examples
+
+```rescript
+Object.assign({"a": 1}, {"a": 2}) // {"a": 2}
+Object.assign({"a": 1, "b": 2}, {"a": 0}) // {"a": 0, "b": 2}
+Object.assign({"a": 1}, {"a": null}) // {"a": null}
+```
+*/
+@val
+external assign: ({..}, {..}) => {..} = "Object.assign"
+
+/**
+`assignMany(target, sources)` copies enumerable own properties from each source to the target, overwriting properties with the same name. Later sources' properties overwrite earlier ones. It returns the modified target object. A deep clone is not created; properties are copied by reference.
+
+**Note:** ReScript provides [first-class support for immutable objects](https://rescript-lang.org/docs/manual/latest/object), including spreading one object into another. This is often more convenient than using `assign` or `assignMany`.  
+
+See [Object.assign on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign) or [ECMAScript Language Specification](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.assign).
+*/
+@variadic
+@val
+external assignMany: ({..}, array<{..}>) => {..} = "Object.assign"
+
+@val external copy: (@as(json`{}`) _, {..} as 'a) => 'a = "Object.assign"
+
+/**
+`get` gets the value of a property by name. Returns `None` if the property does not exist or has the value `undefined`. Otherwise returns `Some`, including if the value is `null`.
+
+## Examples
+
+```rescript
+{"a": 1}->Object.get("a") // Some(1)
+{"a": 1}->Object.get("b") // None
+{"a": undefined}->Object.get("a") // None
+{"a": null}->Object.get("a") // Some(null)
+{"a": 1}->Object.get("toString")->Option.isSome // true
+```
+*/
+@get_index
+external get: ({..}, string) => option<'a> = ""
+
+/**
+`getSymbol` gets the value of a property by symbol. Returns `None` if the property does not exist or has the value `undefined`. Otherwise returns `Some`, including if the value is `null`.
+
+## Examples
+
+```rescript
+let fruit = Symbol.make("fruit")
+let x = Object.make()
+x->Object.setSymbol(fruit, "banana")
+x->Object.getSymbol(fruit) // Some("banana")
+```
+*/
+@get_index
+external getSymbol: ({..}, Symbol.t) => option<'a> = ""
+
+@get_index external getSymbolUnsafe: ({..}, Symbol.t) => 'a = ""
+
+/**
+`set(name, value)` assigns a value to the named object property, overwriting the previous value if any. See [Working with Objects on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Working_with_Objects#objects_and_properties)
+
+## Examples
+
+```rescript
+{"a": 1}->Object.set("a", 2) // {"a": 2}
+{"a": 1}->Object.set("a", None) // {"a": None}
+{"a": 1}->Object.set("b", 2) // {"a": 1, "b": 2}
+```
+*/
+@set_index
+external set: ({..}, string, 'a) => unit = ""
+
+@set_index external setSymbol: ({..}, Symbol.t, 'a) => unit = ""
+
+/**
+`keysToArray` returns an array of an object's own enumerable string-keyed property names. See [ECMAScript Language Specification](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.keys) 
+or [Object.keys on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/keys).
+
+## Examples
+
+```rescript
+{"a": 1, "b": 2}->Object.keysToArray // ["a", "b"]
+{"a": None}->Object.keysToArray // ["a"]
+Object.make()->Object.keysToArray // []
+```
+*/
+@val
+external keysToArray: {..} => array<string> = "Object.keys"
+
+/**
+`hasOwnProperty` determines whether the object has the specified property as its **own** property, as opposed to inheriting it. See [hasOwnProperty on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty)
+
+## Examples
+
+```rescript
+let point = {"x": 1, "y": 2}
+{"a": 1}->Object.hasOwnProperty("a") // true
+{"a": 1}->Object.hasOwnProperty("b") // false
+{"a": 1}->Object.hasOwnProperty("toString") // false
+```
+*/
+@val
+external hasOwnProperty: ({..}, string) => bool = "Object.prototype.hasOwnProperty.call"
+
+/**
+`seal` seals an object. Sealing an object prevents extensions and makes existing properties non-configurable. A sealed object has a fixed set of properties. Unlike `freeze`, values of existing properties can still be changed as long as they are writable. 
+
+**Note:** `seal` returns the same object that was passed in; it does not create a copy. Any attempt to delete or add properties to a sealed object will fail, either silently or by throwing an error. 
+
+See [ECMAScript Language Specification](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.seal) and [Object.seal on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/seal)
+
+## Examples
+
+```rescript
+let point = {"x": 1, "y": 2}
+point->Object.set("x", -7) // succeeds
+point->Object.seal->ignore
+point->Object.set("z", 9) // fails
+point->Object.set("x", 13) // succeeds
+```
+*/
+@val
+external seal: ({..} as 'a) => 'a = "Object.seal"
+
+/**
+`preventExtensions` prevents new properties from being added to the object. It modifies the object (rather than creating a copy) and returns it.
+
+See [ECMAScript Language Specification](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.preventextensions) and [Object.preventExtensions on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/preventExtensions)
+
+## Examples
+
+```rescript
+let obj = {"a": 1}
+obj->Object.set("b", 2) // succeeds
+obj->Object.preventExtensions->ignore
+obj->Object.set("c", 3) // fails
+```
+*/
+@val
+external preventExtensions: ({..} as 'a) => 'a = "Object.preventExtensions"
+
+/**
+`freeze` freezes an object. Freezing an object makes existing properties non-writable and prevents extensions. Once an object is frozen, new properties cannot be be added, existing properties cannot be removed, and their values cannot be changed.
+
+**Note:** `freeze` returns the same object that was passed in; it does not create a frozen copy. Any attempt to change a frozen object will fail, either silently or by throwing an exception.
+
+See [ECMAScript Language Specification](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.isfrozen) and [Object.isFrozen on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isFrozen).
+
+## Examples
+
+ ```rescript
+let obj = {"a": 1}
+obj->Object.set("a", 2) // succeeds
+obj->Object.freeze->ignore
+obj->Object.set("a", 3) // fails
+```
+*/
+@val
+external freeze: ({..} as 'a) => 'a = "Object.freeze"
+
+/**
+`isSealed` determines if an object is sealed. A sealed object has a fixed set of properties.
+
+See [ECMAScript Language Specification](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.issealed) and [Object.isSealed on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isSealed)
+
+## Examples
+
+```rescript
+let point = {"x": 1, "y": 3}->Object.seal
+let pointIsSealed = point->Object.isSealed // true
+let fruit = {"name": "Apple" }
+let fruitIsSealed = fruit->Object.isSealed // false
+ ```
+*/
+@val
+external isSealed: 'a => bool = "Object.isSealed"
+
+/**
+`isFrozen` determines if an object is frozen. An object is frozen if an only if it is not extensible, all its properties are non-configurable, and all its data properties are non-writable.
+
+See [ECMAScript Language Specification](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.isfrozen) and [Object.isFrozen on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isFrozen).
+
+## Examples
+
+```rescript
+let point = {"x": 1, "y": 3}->Object.freeze
+let pointIsFrozen = point->Object.isFrozen // true
+let fruit = {"name": "Apple" }
+let fruitIsFrozen = fruit->Object.isFrozen // false
+ ```
+*/
+@val
+external isFrozen: 'a => bool = "Object.isFrozen"
+
+/**
+`isExtensible` determines if an object is extensible (whether it can have new properties added to it).
+
+See [ECMAScript Language Specification](https://tc39.es/ecma262/multipage/fundamental-objects.html#sec-object.isextensible) and [Object.isExtensible on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isExtensible)
+
+## Examples
+
+```rescript
+let obj = {"a": 1}
+obj->Object.isExtensible // true
+obj->Object.preventExtensions->ignore
+obj->Object.isExtensible // false
+```
+*/
+@val
+external isExtensible: 'a => bool = "Object.isExtensible"
diff --git a/runtime/Option.res b/runtime/Option.res
new file mode 100644
index 0000000000..4fcc8cfbb2
--- /dev/null
+++ b/runtime/Option.res
@@ -0,0 +1,106 @@
+/* Copyright (C) 2017 Hongbo Zhang, Authors of ReScript
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+let filter = (opt, p) =>
+  switch opt {
+  | Some(x) as option if p(x) => option
+  | _ => None
+  }
+
+let forEach = (opt, f) =>
+  switch opt {
+  | Some(x) => f(x)
+  | None => ()
+  }
+
+let getExn = (x, ~message=?) =>
+  switch x {
+  | Some(x) => x
+  | None =>
+    Error.panic(
+      switch message {
+      | None => "Option.getExn called for None value"
+      | Some(message) => message
+      },
+    )
+  }
+
+external getUnsafe: option<'a> => 'a = "%identity"
+
+let mapOr = (opt, default, f) =>
+  switch opt {
+  | Some(x) => f(x)
+  | None => default
+  }
+
+let mapWithDefault = mapOr
+
+let map = (opt, f) =>
+  switch opt {
+  | Some(x) => Some(f(x))
+  | None => None
+  }
+
+let flatMap = (opt, f) =>
+  switch opt {
+  | Some(x) => f(x)
+  | None => None
+  }
+
+let getOr = (opt, default) =>
+  switch opt {
+  | Some(x) => x
+  | None => default
+  }
+
+let getWithDefault = getOr
+
+let orElse = (opt, other) =>
+  switch opt {
+  | Some(_) as some => some
+  | None => other
+  }
+
+let isSome = x =>
+  switch x {
+  | Some(_) => true
+  | None => false
+  }
+
+let isNone = x => x == None
+
+let equal = (a, b, eq) =>
+  switch (a, b) {
+  | (Some(a), Some(b)) => eq(a, b)
+  | (None, None) => true
+  | (None, Some(_)) | (Some(_), None) => false
+  }
+
+let compare = (a, b, cmp) =>
+  switch (a, b) {
+  | (Some(a), Some(b)) => cmp(a, b)
+  | (None, Some(_)) => Ordering.less
+  | (Some(_), None) => Ordering.greater
+  | (None, None) => Ordering.equal
+  }
diff --git a/runtime/Option.resi b/runtime/Option.resi
new file mode 100644
index 0000000000..16efdba52c
--- /dev/null
+++ b/runtime/Option.resi
@@ -0,0 +1,255 @@
+/* Copyright (C) 2017 Authors of ReScript
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/***
+We represent the existence and nonexistence of a value by wrapping it with
+the `option` type. In order to make it a bit more convenient to work with
+option-types, we provide utility-functions for it.
+
+The `option` type is a part of the ReScript standard library which is defined
+like this:
+
+```rescript
+type option<'a> = None | Some('a)
+```
+
+```rescript
+let someString: option<string> = Some("hello")
+```
+*/
+
+/**
+`filter(opt, f)` applies `f` to `opt`, if `f` returns `true`, then it returns `Some(value)`, otherwise returns `None`.
+
+## Examples
+
+```rescript
+Option.filter(Some(10), x => x > 5) // Some(10)
+Option.filter(Some(4), x => x > 5) // None
+Option.filter(None, x => x > 5) // None
+```
+*/
+let filter: (option<'a>, 'a => bool) => option<'a>
+
+/**
+`forEach(opt, f)` call `f` on `opt`. if `opt` is `Some(value)`, then if calls
+`f`, otherwise returns `unit`.
+
+## Examples
+
+```rescript
+Option.forEach(Some("thing"), x => Console.log(x)) // logs "thing"
+Option.forEach(None, x => Console.log(x)) // returns ()
+```
+*/
+let forEach: (option<'a>, 'a => unit) => unit
+
+/**
+`getExn(opt, ~message=?)` returns `value` if `opt` is `Some(value)`, otherwise raises an exception with the message provided, or a generic message if no message was provided.
+
+```rescript
+Option.getExn(Some(3)) // 3
+Option.getExn(None) /* Raises an Error */
+Option.getExn(None, ~message="was None!") /* Raises an Error with the message "was None!" */
+```
+
+## Exceptions
+
+- Raises an error if `opt` is `None`
+*/
+let getExn: (option<'a>, ~message: string=?) => 'a
+
+/**
+`getUnsafe(opt)` returns `value` if `opt` is `Some(value)`, otherwise `undefined`.
+
+## Examples
+
+```rescript
+Option.getUnsafe(Some(3)) == 3
+Option.getUnsafe(None: option<int>) // Returns `undefined`, which is not a valid `int`
+```
+
+## Notes
+
+- This is an unsafe operation. It assumes `value` is not `None`, and may cause undefined behaviour if it is.
+*/
+external getUnsafe: option<'a> => 'a = "%identity"
+
+/**
+`mapOr(opt, default, f)` returns `f(value)` if `opt` is `Some(value)`, otherwise `default`.
+
+## Examples
+
+```rescript
+let someValue = Some(3)
+someValue->Option.mapOr(0, x => x + 5) // 8
+
+let noneValue = None
+noneValue->Option.mapOr(0, x => x + 5) // 0
+```
+*/
+let mapOr: (option<'a>, 'b, 'a => 'b) => 'b
+
+@deprecated("Use mapOr instead")
+let mapWithDefault: (option<'a>, 'b, 'a => 'b) => 'b
+
+/**
+`map(opt, f)` returns `Some(f(value))` if `opt` is `Some(value)`, otherwise `None`.
+
+## Examples
+
+```rescript
+Option.map(Some(3), x => x * x) // Some(9)
+Option.map(None, x => x * x) // None
+```
+*/
+let map: (option<'a>, 'a => 'b) => option<'b>
+
+/**
+`flatMap(opt, f)` returns `f(value)` if `opt` is `Some(value)`, otherwise `None`.
+
+## Examples
+
+```rescript
+let addIfAboveOne = value =>
+  if (value > 1) {
+    Some(value + 1)
+  } else {
+    None
+  }
+
+Option.flatMap(Some(2), addIfAboveOne) // Some(3)
+Option.flatMap(Some(-4), addIfAboveOne) // None
+Option.flatMap(None, addIfAboveOne) // None
+```
+*/
+let flatMap: (option<'a>, 'a => option<'b>) => option<'b>
+
+/**
+`getOr(opt, default)` returns `value` if `opt` is `Some(value)`, otherwise `default`.
+
+## Examples
+
+```rescript
+Option.getOr(None, "Banana") // Banana
+Option.getOr(Some("Apple"), "Banana") // Apple
+
+let greet = (firstName: option<string>) =>
+  "Greetings " ++ firstName->Option.getOr("Anonymous")
+
+Some("Jane")->greet // "Greetings Jane"
+None->greet // "Greetings Anonymous"
+```
+*/
+let getOr: (option<'a>, 'a) => 'a
+
+@deprecated("Use getOr instead")
+let getWithDefault: (option<'a>, 'a) => 'a
+
+/**
+`orElse(opt1, opt2)` returns `opt2` if `opt1` is `None`, otherwise `opt1`.
+
+## Examples
+
+```rescript
+Option.orElse(Some(1812), Some(1066)) == Some(1812)
+Option.orElse(None, Some(1066)) == Some(1066)
+Option.orElse(None, None) == None
+```
+*/
+let orElse: (option<'a>, option<'a>) => option<'a>
+
+/**
+`isSome(opt)` returns `true` if `opt` is `Some(value)`, otherwise returns `false`.
+
+## Examples
+
+```rescript
+Option.isSome(None) // false
+Option.isSome(Some(1)) // true
+```
+*/
+let isSome: option<'a> => bool
+
+/**
+`isNone(opt)` returns `true` if `opt` is `None`, false otherwise.
+
+## Examples
+
+```rescript
+Option.isNone(None) // true
+Option.isNone(Some(1)) // false
+```
+*/
+let isNone: option<'a> => bool
+
+/**
+`equal(opt1, opt2, f)` evaluates two optional values for equality with respect to a predicate function `f`. If both `opt1` and `opt2` are `None`, returns `true`.
+If one of the arguments is `Some(value)` and the other is `None`, returns
+`false`.
+If arguments are `Some(value1)` and `Some(value2)`, returns the result of
+`f(value1, value2)`, the predicate function `f` must return a bool.
+
+## Examples
+
+```rescript
+let clockEqual = (a, b) => mod(a, 12) == mod(b, 12)
+
+open Option
+
+equal(Some(3), Some(15), clockEqual) // true
+equal(Some(3), None, clockEqual) // false
+equal(None, Some(3), clockEqual) // false
+equal(None, None, clockEqual) // true
+```
+*/
+let equal: (option<'a>, option<'b>, ('a, 'b) => bool) => bool
+
+/**
+`compare(opt1, opt2, f)` compares two optional values with respect to given `f`.
+
+If both `opt1` and `opt2` are `None`, it returns `0.`. If the first argument is `Some(value1)` and the second is `None`, returns `1.` (something is greater than nothing).
+
+If the first argument is `None` and the second is `Some(value2)`, returns `-1.`
+(nothing is less than something).
+
+If the arguments are `Some(value1)` and `Some(value2)`, returns the result of
+`f(value1, value2)`, `f` takes two arguments and returns `-1.` if the first
+argument is less than the second, `0.` if the arguments are equal, and `1.` if
+the first argument is greater than the second.
+
+## Examples
+
+```rescript
+let clockCompare = (a, b) => Int.compare(mod(a, 12), mod(b, 12))
+
+Option.compare(Some(3), Some(15), clockCompare) // 0.
+Option.compare(Some(3), Some(14), clockCompare) // 1.
+Option.compare(Some(2), Some(15), clockCompare) // (-1.)
+Option.compare(None, Some(15), clockCompare) // (-1.)
+Option.compare(Some(14), None, clockCompare) // 1.
+Option.compare(None, None, clockCompare) // 0.
+```
+*/
+let compare: (option<'a>, option<'b>, ('a, 'b) => Ordering.t) => Ordering.t
diff --git a/runtime/Ordering.res b/runtime/Ordering.res
new file mode 100644
index 0000000000..c22a9ec4cb
--- /dev/null
+++ b/runtime/Ordering.res
@@ -0,0 +1,13 @@
+type t = float
+
+@inline let less = -1.
+@inline let equal = 0.
+@inline let greater = 1.
+
+let isLess = ord => ord < equal
+let isEqual = ord => ord == equal
+let isGreater = ord => ord > equal
+
+let invert = ord => -.ord
+
+let fromInt = n => n < 0 ? less : n > 0 ? greater : equal
diff --git a/runtime/Pervasives.res b/runtime/Pervasives.res
index 603d2d811a..d8873a1f13 100644
--- a/runtime/Pervasives.res
+++ b/runtime/Pervasives.res
@@ -6,313 +6,555 @@
    If the type exported here is also exported in modules from others,
    you will get a type not equivalent.
 */
-module Pervasives = {
-  /* Internal */
-  @deprecated("Do not use. This will be removed in v13")
-  external __unsafe_cast: 'a => 'b = "%identity"
+@deprecated("Do not use. This will be removed in v13")
+external /* Internal */
 
-  /* Exceptions */
+__unsafe_cast: 'a => 'b = "%identity"
 
-  external raise: exn => 'a = "%raise"
+/* Exceptions */
 
-  @deprecated("Use custom exception instead")
-  let failwith = s => raise(Failure(s))
+external raise: exn => 'a = "%raise"
 
-  @deprecated("Use custom exception instead")
-  let invalid_arg = s => raise(Invalid_argument(s))
+@deprecated("Use custom exception instead")
+let failwith = s => raise(Failure(s))
 
-  @deprecated("Use custom exception instead") exception Exit
+@deprecated("Use custom exception instead")
+let invalid_arg = s => raise(Invalid_argument(s))
 
-  /* Composition operators */
+@deprecated("Use custom exception instead") exception Exit
 
-  external \"|>": ('a, 'a => 'b) => 'b = "%revapply"
-  external \"@@": ('a => 'b, 'a) => 'b = "%apply"
+/* Composition operators */
 
-  /* Debugging */
+external \"|>": ('a, 'a => 'b) => 'b = "%revapply"
+external \"@@": ('a => 'b, 'a) => 'b = "%apply"
 
-  external __LOC__: string = "%loc_LOC"
-  external __FILE__: string = "%loc_FILE"
-  external __LINE__: int = "%loc_LINE"
-  external __MODULE__: string = "%loc_MODULE"
-  external __POS__: (string, int, int, int) = "%loc_POS"
+/* Debugging */
 
-  external __LOC_OF__: 'a => (string, 'a) = "%loc_LOC"
-  external __LINE_OF__: 'a => (int, 'a) = "%loc_LINE"
-  external __POS_OF__: 'a => ((string, int, int, int), 'a) = "%loc_POS"
+external __LOC__: string = "%loc_LOC"
+external __FILE__: string = "%loc_FILE"
+external __LINE__: int = "%loc_LINE"
+external __MODULE__: string = "%loc_MODULE"
+external __POS__: (string, int, int, int) = "%loc_POS"
 
-  /* Comparisons */
+external __LOC_OF__: 'a => (string, 'a) = "%loc_LOC"
+external __LINE_OF__: 'a => (int, 'a) = "%loc_LINE"
+external __POS_OF__: 'a => ((string, int, int, int), 'a) = "%loc_POS"
 
-  external \"=": ('a, 'a) => bool = "%equal"
-  external \"<>": ('a, 'a) => bool = "%notequal"
-  external \"<": ('a, 'a) => bool = "%lessthan"
-  external \">": ('a, 'a) => bool = "%greaterthan"
-  external \"<=": ('a, 'a) => bool = "%lessequal"
-  external \">=": ('a, 'a) => bool = "%greaterequal"
-  external compare: ('a, 'a) => int = "%compare"
-  external min: ('a, 'a) => 'a = "%min"
-  external max: ('a, 'a) => 'a = "%max"
-  external \"==": ('a, 'a) => bool = "%eq"
-  external \"!=": ('a, 'a) => bool = "%noteq"
+/* Comparisons */
 
-  /* Boolean operations */
+external \"=": ('a, 'a) => bool = "%equal"
+external \"<>": ('a, 'a) => bool = "%notequal"
+external \"<": ('a, 'a) => bool = "%lessthan"
+external \">": ('a, 'a) => bool = "%greaterthan"
+external \"<=": ('a, 'a) => bool = "%lessequal"
+external \">=": ('a, 'a) => bool = "%greaterequal"
+external compare: ('a, 'a) => int = "%compare"
+external min: ('a, 'a) => 'a = "%min"
+external max: ('a, 'a) => 'a = "%max"
+external \"==": ('a, 'a) => bool = "%eq"
+external \"!=": ('a, 'a) => bool = "%noteq"
 
-  external not: bool => bool = "%boolnot"
+/* Boolean operations */
 
-  external \"&&": (bool, bool) => bool = "%sequand"
+external not: bool => bool = "%boolnot"
 
-  external \"||": (bool, bool) => bool = "%sequor"
+external \"&&": (bool, bool) => bool = "%sequand"
 
-  /* Integer operations */
+external \"||": (bool, bool) => bool = "%sequor"
 
-  external \"~-": int => int = "%negint"
-  external \"~+": int => int = "%identity"
-  external succ: int => int = "%succint"
-  external pred: int => int = "%predint"
-  external \"+": (int, int) => int = "%addint"
-  external \"-": (int, int) => int = "%subint"
-  external \"*": (int, int) => int = "%mulint"
-  external \"/": (int, int) => int = "%divint"
-  external mod: (int, int) => int = "%modint"
+/* Integer operations */
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let abs = x =>
-    if x >= 0 {
-      x
-    } else {
-      -x
-    }
+external \"~-": int => int = "%negint"
+external \"~+": int => int = "%identity"
+external succ: int => int = "%succint"
+external pred: int => int = "%predint"
+external \"+": (int, int) => int = "%addint"
+external \"-": (int, int) => int = "%subint"
+external \"*": (int, int) => int = "%mulint"
+external \"/": (int, int) => int = "%divint"
+external mod: (int, int) => int = "%modint"
+
+@deprecated("Use Core instead. This will be removed in v13")
+let abs = x =>
+  if x >= 0 {
+    x
+  } else {
+    -x
+  }
 
-  external land: (int, int) => int = "%andint"
-  external lor: (int, int) => int = "%orint"
-  external lxor: (int, int) => int = "%xorint"
+external land: (int, int) => int = "%andint"
+external lor: (int, int) => int = "%orint"
+external lxor: (int, int) => int = "%xorint"
 
-  let lnot = x => lxor(x, -1)
+let lnot = x => lxor(x, -1)
 
-  external lsl: (int, int) => int = "%lslint"
-  external lsr: (int, int) => int = "%lsrint"
-  external asr: (int, int) => int = "%asrint"
+external lsl: (int, int) => int = "%lslint"
+external lsr: (int, int) => int = "%lsrint"
+external asr: (int, int) => int = "%asrint"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let max_int = lsr(-1, 1)
+@deprecated("Use Core instead. This will be removed in v13")
+let max_int = lsr(-1, 1)
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let min_int =
-    max_int + 1
+@deprecated("Use Core instead. This will be removed in v13")
+let min_int =
+  max_int + 1
 
-  /* Floating-point operations */
+/* Floating-point operations */
 
-  external \"~-.": float => float = "%negfloat"
-  external \"~+.": float => float = "%identity"
-  external \"+.": (float, float) => float = "%addfloat"
-  external \"-.": (float, float) => float = "%subfloat"
-  external \"*.": (float, float) => float = "%mulfloat"
-  external \"/.": (float, float) => float = "%divfloat"
+external \"~-.": float => float = "%negfloat"
+external \"~+.": float => float = "%identity"
+external \"+.": (float, float) => float = "%addfloat"
+external \"-.": (float, float) => float = "%subfloat"
+external \"*.": (float, float) => float = "%mulfloat"
+external \"/.": (float, float) => float = "%divfloat"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external \"**": (float, float) => float = "pow"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external \"**": (float, float) => float = "pow"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external exp: float => float = "exp"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external exp: float => float = "exp"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external acos: float => float = "acos"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external acos: float => float = "acos"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external asin: float => float = "asin"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external asin: float => float = "asin"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external atan: float => float = "atan"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external atan: float => float = "atan"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external atan2: (float, float) => float = "atan2"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external atan2: (float, float) => float = "atan2"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external cos: float => float = "cos"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external cos: float => float = "cos"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external cosh: float => float = "cosh"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external cosh: float => float = "cosh"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external log: float => float = "log"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external log: float => float = "log"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external log10: float => float = "log10"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external log10: float => float = "log10"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external log1p: float => float = "log1p"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external log1p: float => float = "log1p"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external sin: float => float = "sin"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external sin: float => float = "sin"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external sinh: float => float = "sinh"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external sinh: float => float = "sinh"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external sqrt: float => float = "sqrt"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external sqrt: float => float = "sqrt"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external tan: float => float = "tan"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external tan: float => float = "tan"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external tanh: float => float = "tanh"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external tanh: float => float = "tanh"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external ceil: float => float = "ceil"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external ceil: float => float = "ceil"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external floor: float => float = "floor"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external floor: float => float = "floor"
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
-  external abs_float: float => float = "abs"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Math")
+external abs_float: float => float = "abs"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  external mod_float: float => float = "%modfloat"
+@deprecated("Use Core instead. This will be removed in v13")
+external mod_float: float => float = "%modfloat"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  external float: int => float = "%floatofint"
+@deprecated("Use Core instead. This will be removed in v13")
+external float: int => float = "%floatofint"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  external float_of_int: int => float = "%floatofint"
+@deprecated("Use Core instead. This will be removed in v13")
+external float_of_int: int => float = "%floatofint"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  external truncate: float => int = "%intoffloat"
+@deprecated("Use Core instead. This will be removed in v13")
+external truncate: float => int = "%intoffloat"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  external int_of_float: float => int = "%intoffloat"
+@deprecated("Use Core instead. This will be removed in v13")
+external int_of_float: float => int = "%intoffloat"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let infinity = 0x1p2047
+@deprecated("Use Core instead. This will be removed in v13")
+let infinity = 0x1p2047
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let neg_infinity = -0x1p2047
+@deprecated("Use Core instead. This will be removed in v13")
+let neg_infinity = -0x1p2047
 
-  @deprecated("Use Core instead. This will be removed in v13") @val @scope("Number")
-  external nan: float = "NaN"
+@deprecated("Use Core instead. This will be removed in v13") @val @scope("Number")
+external nan: float = "NaN"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let max_float = 1.79769313486231571e+308 /* 0x1.ffff_ffff_ffff_fp+1023 */
+@deprecated("Use Core instead. This will be removed in v13")
+let max_float = 1.79769313486231571e+308 /* 0x1.ffff_ffff_ffff_fp+1023 */
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let min_float = 2.22507385850720138e-308 /* 0x1p-1022 */
+@deprecated("Use Core instead. This will be removed in v13")
+let min_float = 2.22507385850720138e-308 /* 0x1p-1022 */
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let epsilon_float = 2.22044604925031308e-16 /* 0x1p-52 */
+@deprecated("Use Core instead. This will be removed in v13")
+let epsilon_float = 2.22044604925031308e-16 /* 0x1p-52 */
 
-  @deprecated("Do not use. This will be removed in v13")
-  type fpclass =
-    | FP_normal
-    | FP_subnormal
-    | FP_zero
-    | FP_infinite
-    | FP_nan
+@deprecated("Do not use. This will be removed in v13")
+type fpclass =
+  | FP_normal
+  | FP_subnormal
+  | FP_zero
+  | FP_infinite
+  | FP_nan
 
-  @deprecated("Do not use. This will be removed in v13")
-  let classify_float = (x: float): fpclass =>
-    if (%raw(`isFinite`): _ => _)(x) {
-      if abs_float(x) >= /* 0x1p-1022 */ /* 2.22507385850720138e-308 */ min_float {
-        FP_normal
-      } else if x != 0. {
-        FP_subnormal
-      } else {
-        FP_zero
-      }
-    } else if (%raw(`isNaN`): _ => _)(x) {
-      FP_nan
+@deprecated("Do not use. This will be removed in v13")
+let classify_float = (x: float): fpclass =>
+  if (%raw(`isFinite`): _ => _)(x) {
+    if abs_float(x) >= /* 0x1p-1022 */ /* 2.22507385850720138e-308 */ min_float {
+      FP_normal
+    } else if x != 0. {
+      FP_subnormal
     } else {
-      FP_infinite
+      FP_zero
     }
+  } else if (%raw(`isNaN`): _ => _)(x) {
+    FP_nan
+  } else {
+    FP_infinite
+  }
 
-  /* String and byte sequence operations -- more in modules String and Bytes */
+/* String and byte sequence operations -- more in modules String and Bytes */
 
-  external \"^": (string, string) => string = "%string_concat"
+external \"^": (string, string) => string = "%string_concat"
 
-  /* Character operations -- more in module Char */
+/* Character operations -- more in module Char */
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  external int_of_char: char => int = "%identity"
+@deprecated("Use Core instead. This will be removed in v13")
+external int_of_char: char => int = "%identity"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  external unsafe_char_of_int: int => char = "%identity"
+@deprecated("Use Core instead. This will be removed in v13")
+external unsafe_char_of_int: int => char = "%identity"
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let char_of_int = n =>
-    if n < 0 || n > 255 {
-      invalid_arg("char_of_int")
-    } else {
-      unsafe_char_of_int(n)
-    }
+@deprecated("Use Core instead. This will be removed in v13")
+let char_of_int = n =>
+  if n < 0 || n > 255 {
+    invalid_arg("char_of_int")
+  } else {
+    unsafe_char_of_int(n)
+  }
 
-  /* Unit operations */
+/* Unit operations */
 
-  external ignore: 'a => unit = "%ignore"
+external ignore: 'a => unit = "%ignore"
 
-  /* Pair operations */
+/* Pair operations */
 
-  external fst: (('a, 'b)) => 'a = "%field0"
-  external snd: (('a, 'b)) => 'b = "%field1"
+external fst: (('a, 'b)) => 'a = "%field0"
+external snd: (('a, 'b)) => 'b = "%field1"
 
-  /* References */
+/* References */
 
-  type ref<'a> = {mutable contents: 'a}
-  external ref: 'a => ref<'a> = "%makeref"
-  external \"!": ref<'a> => 'a = "%refget"
-  external \":=": (ref<'a>, 'a) => unit = "%refset"
-  external incr: ref<int> => unit = "%incr"
-  external decr: ref<int> => unit = "%decr"
+type ref<'a> = {mutable contents: 'a}
+external ref: 'a => ref<'a> = "%makeref"
+external \"!": ref<'a> => 'a = "%refget"
+external \":=": (ref<'a>, 'a) => unit = "%refset"
+external incr: ref<int> => unit = "%incr"
+external decr: ref<int> => unit = "%decr"
 
-  /* String conversion functions */
+/* String conversion functions */
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let string_of_bool = b =>
-    if b {
-      "true"
-    } else {
-      "false"
-    }
+@deprecated("Use Core instead. This will be removed in v13")
+let string_of_bool = b =>
+  if b {
+    "true"
+  } else {
+    "false"
+  }
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let bool_of_string = param =>
-    switch param {
-    | "true" => true
-    | "false" => false
-    | _ => invalid_arg("bool_of_string")
-    }
+@deprecated("Use Core instead. This will be removed in v13")
+let bool_of_string = param =>
+  switch param {
+  | "true" => true
+  | "false" => false
+  | _ => invalid_arg("bool_of_string")
+  }
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let bool_of_string_opt = param =>
-    switch param {
-    | "true" => Some(true)
-    | "false" => Some(false)
-    | _ => None
-    }
+@deprecated("Use Core instead. This will be removed in v13")
+let bool_of_string_opt = param =>
+  switch param {
+  | "true" => Some(true)
+  | "false" => Some(false)
+  | _ => None
+  }
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  external string_of_int: int => string = "String"
+@deprecated("Use Core instead. This will be removed in v13")
+external string_of_int: int => string = "String"
 
-  @deprecated("Use Core instead. This will be removed in v13") @scope("Number")
-  external int_of_string: string => int = "parseInt"
+@deprecated("Use Core instead. This will be removed in v13") @scope("Number")
+external int_of_string: string => int = "parseInt"
 
-  let int_of_string_opt = s =>
-    switch int_of_string(s) {
-    | n if n == %raw("NaN") => None
-    | n => Some(n)
-    }
+let int_of_string_opt = s =>
+  switch int_of_string(s) {
+  | n if n == %raw("NaN") => None
+  | n => Some(n)
+  }
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  external string_get: (string, int) => char = "%string_safe_get"
+@deprecated("Use Core instead. This will be removed in v13")
+external string_get: (string, int) => char = "%string_safe_get"
 
-  /* List operations -- more in module List */
+/* List operations -- more in module List */
 
-  @deprecated("Use Core instead. This will be removed in v13")
-  let rec \"@" = (l1, l2) =>
-    switch l1 {
-    | list{} => l2
-    | list{hd, ...tl} => list{hd, ...\"@"(tl, l2)}
-    }
+@deprecated("Use Core instead. This will be removed in v13")
+let rec \"@" = (l1, l2) =>
+  switch l1 {
+  | list{} => l2
+  | list{hd, ...tl} => list{hd, ...\"@"(tl, l2)}
+  }
+
+/* Miscellaneous */
 
-  /* Miscellaneous */
+type int32 = int
+
+/***
+Bindings to functions available in the global JavaScript scope.
+*/
+
+/**
+An `id` representing a timeout started via `setTimeout`.
+
+See [`setTimeout`](https://developer.mozilla.org/en-US/docs/Web/API/setTimeout) on MDN.
+*/
+type timeoutId = Js_global.timeoutId
+
+/**
+`setTimeout(callback, durationInMilliseconds)` starts a timer that will execute `callback` after `durationInMilliseconds`.
+
+See [`setTimeout`](https://developer.mozilla.org/en-US/docs/Web/API/setTimeout) on MDN.
+
+## Examples
+```rescript
+// Log to the console after 2 seconds (2000 milliseconds).
+let timeoutId = setTimeout(() => {
+  Console.log("This prints in 2 seconds.")
+}, 2000)
+```
+*/
+@val
+external setTimeout: (unit => unit, int) => timeoutId = "setTimeout"
 
-  type int32 = int
+/**
+`setTimeoutFloat(callback, durationInMilliseconds)` starts a timer that will execute `callback` after `durationInMilliseconds`.
+
+The same as `setTimeout`, but allows you to pass a `float` instead of an `int` for the duration.
+
+See [`setTimeout`](https://developer.mozilla.org/en-US/docs/Web/API/setTimeout) on MDN.
+
+## Examples
+```rescript
+// Log to the console after 2 seconds (2000 milliseconds).
+let timeoutId = setTimeoutFloat(() => {
+  Console.log("This prints in 2 seconds.")
+}, 2000.)
+```
+*/
+@val
+external setTimeoutFloat: (unit => unit, float) => timeoutId = "setTimeout"
+
+/**
+`clearTimeout(timeoutId)` clears a scheduled timeout if it hasn't already executed.
+
+See [`clearTimeout`](https://developer.mozilla.org/en-US/docs/Web/API/clearTimeout) on MDN.
+
+## Examples
+```rescript
+let timeoutId = setTimeout(() => {
+  Console.log("This prints in 2 seconds.")
+}, 2000)
+
+// Clearing the timeout right away, before 2 seconds has passed, means that the above callback logging to the console will never run.
+clearTimeout(timeoutId)
+```
+*/
+@val
+external clearTimeout: timeoutId => unit = "clearTimeout"
+
+/**
+An `id` representing an interval started via `setInterval`.
+
+See [`setInterval`](https://developer.mozilla.org/en-US/docs/Web/API/setInterval) on MDN.
+*/
+type intervalId = Js_global.intervalId
+
+/**
+`setInterval(callback, intervalInMilliseconds)` starts an interval that will execute `callback` every `durationInMilliseconds` milliseconds.
+
+See [`setInterval`](https://developer.mozilla.org/en-US/docs/Web/API/setInterval) on MDN.
+
+## Examples
+```rescript
+// Log to the console ever 2 seconds (2000 milliseconds).
+let intervalId = setInterval(() => {
+  Console.log("This prints every 2 seconds.")
+}, 2000)
+```
+*/
+@val
+external setInterval: (unit => unit, int) => intervalId = "setInterval"
+
+/**
+`setIntervalFloat(callback, intervalInMilliseconds)` starts an interval that will execute `callback` every `durationInMilliseconds` milliseconds.
+
+The same as `setInterval`, but allows you to pass a `float` instead of an `int` for the duration.
+
+See [`setInterval`](https://developer.mozilla.org/en-US/docs/Web/API/setInterval) on MDN.
+
+## Examples
+```rescript
+// Log to the console ever 2 seconds (2000 milliseconds).
+let intervalId = setIntervalFloat(() => {
+  Console.log("This prints every 2 seconds.")
+}, 2000.)
+```
+*/
+@val
+external setIntervalFloat: (unit => unit, float) => intervalId = "setInterval"
+
+/**
+`clearInterval(intervalId)` clears a scheduled interval.
+
+See [`clearInterval`](https://developer.mozilla.org/en-US/docs/Web/API/clearInterval) on MDN.
+
+## Examples
+```rescript
+let intervalId = setInterval(() => {
+  Console.log("This prints in 2 seconds.")
+}, 2000)
+
+// Stop the interval after 10 seconds
+let timeoutId = setTimeout(() => {
+  clearInterval(intervalId)
+}, 10000)
+```
+*/
+@val
+external clearInterval: intervalId => unit = "clearInterval"
+
+/**
+Encodes a URI by replacing characters in the provided string that aren't valid in a URL.
+
+This is intended to operate on full URIs, so it encodes fewer characters than what `encodeURIComponent` does.
+If you're looking to encode just parts of a URI, like a query parameter, prefer `encodeURIComponent`.
+
+See [`encodeURI`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURI) on MDN.
+
+## Examples
+```rescript
+Console.log(encodeURI("https://rescript-lang.org?array=[someValue]"))
+// Logs "https://rescript-lang.org?array=%5BsomeValue%5D" to the console.
+```
+
+*/
+@val
+external encodeURI: string => string = "encodeURI"
+
+/**
+Decodes a previously encoded URI back to a regular string.
+
+This is intended to operate on full URIs, so it decodes fewer characters than what `decodeURIComponent` does.
+If you're looking to decode just parts of a URI, like a query parameter, prefer `decodeURIComponent`.
+
+See [`decodeURI`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/decodeURI) on MDN.
+
+## Examples
+```rescript
+Console.log(decodeURI("https://rescript-lang.org?array=%5BsomeValue%5D"))
+// Logs "https://rescript-lang.org?array=[someValue]" to the console.
+```
+*/
+@val
+external decodeURI: string => string = "decodeURI"
+
+/**
+Encodes a string so it can be used as part of a URI.
+
+See [`encodeURIComponent`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent) on MDN.
+
+## Examples
+```rescript
+Console.log(encodeURIComponent("array=[someValue]"))
+// Logs "array%3D%5BsomeValue%5D" to the console.
+```
+*/
+@val
+external encodeURIComponent: string => string = "encodeURIComponent"
+
+/**
+Decodes a previously URI encoded string back to its original form.
+
+See [`decodeURIComponent`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/decodeURIComponent) on MDN.
+
+## Examples
+```rescript
+Console.log(decodeURIComponent("array%3D%5BsomeValue%5D"))
+// Logs "array=[someValue]" to the console.
+```
+*/
+@val
+external decodeURIComponent: string => string = "decodeURIComponent"
+
+@val external window: Dom.window = "window"
+@val external document: Dom.document = "document"
+@val external globalThis: {..} = "globalThis"
+
+external null: Js.Nullable.t<'a> = "#null"
+external undefined: Js.Nullable.t<'a> = "#undefined"
+external typeof: 'a => Type.t = "#typeof"
+
+/**
+`import(value)` dynamically import a value or function from a ReScript
+module. The import call will return a `promise`, resolving to the dynamically loaded
+value.
+
+## Examples
+
+`Array.res` file:
+
+```rescript
+@send external indexOf: (array<'a>, 'a) => int = "indexOf"
+
+let indexOfOpt = (arr, item) =>
+  switch arr->indexOf(item) {
+  | -1 => None
+  | index => Some(index)
+  }
+```
+In other file you can import the `indexOfOpt` value defined in `Array.res`
+
+```rescript
+let main = async () => {
+  let indexOfOpt = await import(Array.indexOfOpt)
+  let index = indexOfOpt([1, 2], 2)
+  Console.log(index)
 }
+```
+
+Compiles to:
+
+```javascript
+async function main() {
+  var add = await import("./Array.mjs").then(function(m) {
+    return m.indexOfOpt;
+  });
+  var index = indexOfOpt([1, 2], 2);
+  console.log(index);
+}
+```
+*/
+external import: 'a => promise<'a> = "#import"
+
+type null<+'a> = Js.null<'a>
+
+type undefined<+'a> = Js.undefined<'a>
+
+type nullable<+'a> = Js.nullable<'a>
 
-include Pervasives
+let panic = Error.panic
diff --git a/runtime/Pervasives_mini.res b/runtime/Pervasives_mini.res
new file mode 100644
index 0000000000..9c62e80ffe
--- /dev/null
+++ b/runtime/Pervasives_mini.res
@@ -0,0 +1,79 @@
+/* Exceptions */
+external raise: exn => 'a = "%raise"
+
+/* Debugging */
+
+external __LOC__: string = "%loc_LOC"
+external __FILE__: string = "%loc_FILE"
+external __LINE__: int = "%loc_LINE"
+external __MODULE__: string = "%loc_MODULE"
+external __POS__: (string, int, int, int) = "%loc_POS"
+
+external __LOC_OF__: 'a => (string, 'a) = "%loc_LOC"
+external __LINE_OF__: 'a => (int, 'a) = "%loc_LINE"
+external __POS_OF__: 'a => ((string, int, int, int), 'a) = "%loc_POS"
+
+/* Comparisons */
+
+external \"=": ('a, 'a) => bool = "%equal"
+external \"<>": ('a, 'a) => bool = "%notequal"
+external \"<": ('a, 'a) => bool = "%lessthan"
+external \">": ('a, 'a) => bool = "%greaterthan"
+external \"<=": ('a, 'a) => bool = "%lessequal"
+external \">=": ('a, 'a) => bool = "%greaterequal"
+external compare: ('a, 'a) => int = "%compare"
+external min: ('a, 'a) => 'a = "%min"
+external max: ('a, 'a) => 'a = "%max"
+external \"==": ('a, 'a) => bool = "%eq"
+external \"!=": ('a, 'a) => bool = "%noteq"
+
+/* Boolean operations */
+
+external not: bool => bool = "%boolnot"
+
+external \"&&": (bool, bool) => bool = "%sequand"
+
+external \"||": (bool, bool) => bool = "%sequor"
+
+/* Integer operations */
+
+external \"~-": int => int = "%negint"
+external \"~+": int => int = "%identity"
+external succ: int => int = "%succint"
+external pred: int => int = "%predint"
+external \"+": (int, int) => int = "%addint"
+external \"-": (int, int) => int = "%subint"
+external \"*": (int, int) => int = "%mulint"
+external \"/": (int, int) => int = "%divint"
+external mod: (int, int) => int = "%modint"
+
+external land: (int, int) => int = "%andint"
+external lor: (int, int) => int = "%orint"
+external lxor: (int, int) => int = "%xorint"
+
+external lsl: (int, int) => int = "%lslint"
+external lsr: (int, int) => int = "%lsrint"
+external asr: (int, int) => int = "%asrint"
+
+/* Floating-point operations */
+
+external \"~-.": float => float = "%negfloat"
+external \"~+.": float => float = "%identity"
+external \"+.": (float, float) => float = "%addfloat"
+external \"-.": (float, float) => float = "%subfloat"
+external \"*.": (float, float) => float = "%mulfloat"
+external \"/.": (float, float) => float = "%divfloat"
+
+/* String operations */
+
+external \"^": (string, string) => string = "%string_concat"
+
+/* Unit operations */
+
+external ignore: 'a => unit = "%ignore"
+
+/* References */
+
+type ref<'a> = {mutable contents: 'a}
+external ref: 'a => ref<'a> = "%makeref"
+external \":=": (ref<'a>, 'a) => unit = "%refset"
diff --git a/runtime/Promise.res b/runtime/Promise.res
new file mode 100644
index 0000000000..8a4418d2fd
--- /dev/null
+++ b/runtime/Promise.res
@@ -0,0 +1,112 @@
+type t<+'a> = promise<'a>
+
+@new
+external make: (('a => unit, 'e => unit) => unit) => t<'a> = "Promise"
+
+type promiseAndResolvers<'a> = {
+  promise: t<'a>,
+  resolve: 'a => unit,
+  reject: exn => unit,
+}
+
+@scope("Promise") @val
+external withResolvers: unit => promiseAndResolvers<_> = "withResolvers"
+
+@scope("Promise") @val
+external resolve: 'a => t<'a> = "resolve"
+
+@send external then: (t<'a>, 'a => t<'b>) => t<'b> = "then"
+
+@send
+external thenResolve: (t<'a>, 'a => 'b) => t<'b> = "then"
+
+@send external finally: (t<'a>, unit => unit) => t<'a> = "finally"
+
+@scope("Promise") @val
+external reject: exn => t<_> = "reject"
+
+@scope("Promise") @val
+external all: array<t<'a>> => t<array<'a>> = "all"
+
+@scope("Promise") @val
+external all2: ((t<'a>, t<'b>)) => t<('a, 'b)> = "all"
+
+@scope("Promise") @val
+external all3: ((t<'a>, t<'b>, t<'c>)) => t<('a, 'b, 'c)> = "all"
+
+@scope("Promise") @val
+external all4: ((t<'a>, t<'b>, t<'c>, t<'d>)) => t<('a, 'b, 'c, 'd)> = "all"
+
+@scope("Promise") @val
+external all5: ((t<'a>, t<'b>, t<'c>, t<'d>, t<'e>)) => t<('a, 'b, 'c, 'd, 'e)> = "all"
+
+@scope("Promise") @val
+external all6: ((t<'a>, t<'b>, t<'c>, t<'d>, t<'e>, t<'f>)) => t<('a, 'b, 'c, 'd, 'e, 'f)> = "all"
+
+@tag("status")
+type settledResult<+'a> =
+  | @as("fulfilled") Fulfilled({value: 'a}) | @as("rejected") Rejected({reason: exn})
+
+@scope("Promise") @val
+external allSettled: array<promise<'a>> => promise<array<settledResult<'a>>> = "allSettled"
+
+@scope("Promise") @val
+external allSettled2: ((promise<'a0>, promise<'a1>)) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+)> = "allSettled"
+
+@scope("Promise") @val
+external allSettled3: ((promise<'a0>, promise<'a1>, promise<'a2>)) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+  settledResult<'a2>,
+)> = "allSettled"
+
+@scope("Promise") @val
+external allSettled4: ((promise<'a0>, promise<'a1>, promise<'a2>, promise<'a3>)) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+  settledResult<'a2>,
+  settledResult<'a3>,
+)> = "allSettled"
+
+@scope("Promise") @val
+external allSettled5: (
+  (promise<'a0>, promise<'a1>, promise<'a2>, promise<'a3>, promise<'a4>)
+) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+  settledResult<'a2>,
+  settledResult<'a3>,
+  settledResult<'a4>,
+)> = "allSettled"
+
+@scope("Promise") @val
+external allSettled6: (
+  (promise<'a0>, promise<'a1>, promise<'a2>, promise<'a3>, promise<'a4>, promise<'a5>)
+) => promise<(
+  settledResult<'a0>,
+  settledResult<'a1>,
+  settledResult<'a2>,
+  settledResult<'a3>,
+  settledResult<'a4>,
+  settledResult<'a5>,
+)> = "allSettled"
+
+@send
+external _catch: (t<'a>, exn => t<'a>) => t<'a> = "catch"
+
+let catch = (promise: promise<'a>, callback: exn => promise<'a>): promise<'a> => {
+  _catch(promise, err => {
+    callback(Js.Exn.anyToExnInternal(err))
+  })
+}
+
+@scope("Promise") @val
+external race: array<t<'a>> => t<'a> = "race"
+
+@scope("Promise") @val
+external any: array<t<'a>> => t<'a> = "any"
+
+external done: promise<'a> => unit = "%ignore"
diff --git a/runtime/Promise.resi b/runtime/Promise.resi
new file mode 100644
index 0000000000..5468bf9370
--- /dev/null
+++ b/runtime/Promise.resi
@@ -0,0 +1,445 @@
+// The +'a marks the abstract type parameter as covariant, which essentially means that
+// a value of type 'a is immutable and may not be used in some mutable context.
+//
+// This makes sense for promises, since according to their specification, once a promise has
+// been resolved (with a specific value), it will never change its resolved value.
+//
+// More details about polymorphism / invariance / covariance,... can be found here:
+// https://caml.inria.fr/pub/docs/manual-ocaml/polymorphism.html#ss:variance:abstract-data-types
+
+/***
+Functions for interacting with JavaScript Promise.
+See: [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise).
+*/
+
+type t<+'a> = promise<'a>
+
+/**
+`resolve(value)` creates a resolved Promise with a given `value`.
+See [`Promise.resolve`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/resolve) on MDN.
+
+## Examples
+
+```rescript
+let p = Promise.resolve(5) // promise<int>
+```
+*/
+@val
+@scope("Promise")
+external resolve: 'a => t<'a> = "resolve"
+
+/**
+`reject(exn)` reject a Promise.
+See [`Promise.reject`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/reject) on MDN.
+
+## Examples
+
+```rescript
+exception TestError(string)
+
+let p = Promise.reject(TestError("some rejected value"))
+```
+*/
+@scope("Promise")
+@val
+external reject: exn => t<_> = "reject"
+
+/**
+`make(callback)` creates a new Promise based on a `callback` that receives two
+uncurried functions `resolve` and `reject` for defining the Promise's result.
+
+## Examples
+
+```rescript
+open Promise
+
+let n = 4
+Promise.make((resolve, reject) => {
+  if(n < 5) {
+    resolve(. "success")
+  }
+  else {
+    reject(. "failed")
+  }
+})
+->then(str => {
+  Console.log(str)->resolve
+})
+->catch(_ => {
+  Console.log("Error occurred")
+  resolve()
+})
+->ignore
+```
+*/
+@new
+external make: (('a => unit, 'e => unit) => unit) => t<'a> = "Promise"
+
+type promiseAndResolvers<'a> = {
+  promise: t<'a>,
+  resolve: 'a => unit,
+  reject: exn => unit,
+}
+
+/**
+`withResolvers()` returns a object containing a new promise with functions to resolve or reject it. See [`Promise.withResolvers`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers) on MDN.
+
+## Examples
+
+```rescript
+open Promise
+
+let {promise, resolve, _} = Promise.withResolvers()
+
+setTimeout(() => {
+  resolve(. "success")
+}, 1000)->ignore
+
+promise
+->thenResolve(str => {
+  Console.log(str)
+})
+->ignore
+```
+*/
+@scope("Promise")
+@val
+external withResolvers: unit => promiseAndResolvers<_> = "withResolvers"
+
+/**
+`catch(promise, errorCallback)` registers an exception handler in a promise chain.
+The `errorCallback` receives an `exn` value that can later be refined into a JS
+error or ReScript error. The `errorCallback` needs to return a promise with the
+same type as the consumed promise. See [`Promise.catch`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/catch) on MDN.
+
+## Examples
+
+```rescript
+open Promise
+
+exception SomeError(string)
+
+reject(SomeError("this is an error"))
+->then(_ => {
+  Ok("This result will never be returned")->resolve
+})
+->catch(e => {
+  let msg = switch(e) {
+    | SomeError(msg) => "ReScript error occurred: " ++ msg
+    | Exn.Error(obj) =>
+      switch Exn.message(obj) {
+        | Some(msg) => "JS exception occurred: " ++ msg
+        | None => "Some other JS value has been thrown"
+      }
+    | _ => "Unexpected error occurred"
+  }
+
+  Error(msg)->resolve
+})
+->then(result => {
+  switch result {
+  | Ok(r) => Console.log2("Operation successful: ", r)
+  | Error(msg) => Console.log2("Operation failed: ", msg)
+  }->resolve
+})
+->ignore // Ignore needed for side-effects
+```
+
+In case you want to return another promise in your `callback`, consider using
+`then` instead.
+*/
+let catch: (t<'a>, exn => t<'a>) => t<'a>
+
+/**
+`then(promise, callback)` returns a new promise based on the result of `promise`'s 
+value. The `callback` needs to explicitly return a new promise via `resolve`.
+It is **not allowed** to resolve a nested promise (like `resolve(resolve(1))`).
+See [`Promise.then`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/then) on MDN.
+## Examples
+
+```rescript
+open Promise
+resolve(5)
+->then(num => {
+  resolve(num + 5)
+})
+->then(num => {
+  Console.log2("Your lucky number is: ", num)
+  resolve()
+})
+->ignore
+```
+*/
+@send
+external then: (t<'a>, 'a => t<'b>) => t<'b> = "then"
+
+/**
+`thenResolve(promise, callback)` converts an encapsulated value of a promise
+into another promise wrapped value. It is **not allowed** to return a promise
+within the provided callback (e.g. `thenResolve(value => resolve(value))`).
+
+## Examples
+
+```rescript
+open Promise
+resolve("Anna")
+->thenResolve(str => {
+  "Hello " ++ str
+})
+->thenResolve(str => {
+  Console.log(str)
+})
+->ignore // Ignore needed for side-effects
+```
+
+In case you want to return another promise in your `callback`, consider using
+`then` instead.
+*/
+@send
+external thenResolve: (t<'a>, 'a => 'b) => t<'b> = "then"
+
+/**
+`finally(promise, callback)` is used to execute a function that is called no
+matter if a promise was resolved or rejected. It will return the same `promise`
+it originally received. See [`Promise.finally`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/finally) on MDN.
+
+## Examples
+
+```rescript
+open Promise
+exception SomeError(string)
+let isDone = ref(false)
+
+resolve(5)
+->then(_ => {
+  reject(SomeError("test"))
+})
+->then(v => {
+  Console.log2("final result", v)
+  resolve()
+})
+->catch(_ => {
+  Console.log("Error handled")
+  resolve()
+})
+->finally(() => {
+  Console.log("finally")
+  isDone := true
+})
+->then(() => {
+  Console.log2("isDone:", isDone.contents)
+  resolve()
+})
+->ignore
+```
+*/
+@send
+external finally: (t<'a>, unit => unit) => t<'a> = "finally"
+
+/**
+`race(arr)` runs all promises concurrently and returns promise settles with the eventual state of the first promise that settles. See [`Promise.race`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/race) on MDN.
+
+## Examples
+
+```rescript
+open Promise
+let racer = (ms, name) => {
+  Promise.make((resolve, _) => {
+    setTimeout(() => {
+      resolve(name)
+    }, ms)->ignore
+  })
+}
+
+let promises = [racer(1000, "Turtle"), racer(500, "Hare"), racer(100, "Eagle")]
+
+race(promises)->then(winner => {
+  Console.log("The winner is " ++ winner)
+  resolve()
+})
+```
+*/
+@scope("Promise")
+@val
+external race: array<t<'a>> => t<'a> = "race"
+
+/**
+`any(arr)` runs all promises concurrently and returns promise fulfills when any of the input's promises fulfills, with this first fulfillment value. See [`Promise.any`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/any) on MDN.
+
+## Examples
+
+```rescript
+open Promise
+let racer = (ms, name) => {
+  Promise.make((resolve, _) => {
+    setTimeout(() => {
+      resolve(name)
+    }, ms)->ignore
+  })
+}
+
+let promises = [racer(1000, "Turtle"), racer(500, "Hare"), racer(100, "Eagle")]
+
+any(promises)->then(winner => {
+  Console.log("The winner is " ++ winner)
+  resolve()
+})
+```
+*/
+@scope("Promise")
+@val
+external any: array<t<'a>> => t<'a> = "any"
+
+/**
+`all(promises)` runs all promises concurrently and returns a promise fulfills when all of the input's promises fulfill, with an array of the fulfillment values. See [`Promise.all`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all) on MDN.
+
+```rescript
+open Promise
+let promises = [resolve(1), resolve(2), resolve(3)]
+
+all(promises)
+->then((results) => {
+  results->Array.forEach(num => {
+    Console.log2("Number: ", num)
+  })
+
+  resolve()
+})
+->ignore
+```
+*/
+@scope("Promise")
+@val
+external all: array<t<'a>> => t<array<'a>> = "all"
+
+/**
+`all2((p1, p2))`. Like `all()`, but with a fixed size tuple of 2
+*/
+@scope("Promise")
+@val
+external all2: ((t<'a>, t<'b>)) => t<('a, 'b)> = "all"
+
+/**
+`all3((p1, p2, p3))`. Like `all()`, but with a fixed size tuple of 3
+*/
+@scope("Promise")
+@val
+external all3: ((t<'a>, t<'b>, t<'c>)) => t<('a, 'b, 'c)> = "all"
+
+/**
+`all4((p1, p2, p3, p4))`. Like `all()`, but with a fixed size tuple of 4
+*/
+@scope("Promise")
+@val
+external all4: ((t<'a>, t<'b>, t<'c>, t<'d>)) => t<('a, 'b, 'c, 'd)> = "all"
+
+/**
+`all5((p1, p2, p3, p4, p5))`. Like `all()`, but with a fixed size tuple of 5
+*/
+@scope("Promise")
+@val
+external all5: ((t<'a>, t<'b>, t<'c>, t<'d>, t<'e>)) => t<('a, 'b, 'c, 'd, 'e)> = "all"
+
+/**
+`all6((p1, p2, p4, p5, p6))`. Like `all()`, but with a fixed size tuple of 6
+")*/
+@scope("Promise")
+@val
+external all6: ((t<'a>, t<'b>, t<'c>, t<'d>, t<'e>, t<'f>)) => t<('a, 'b, 'c, 'd, 'e, 'f)> = "all"
+
+@tag("status")
+type settledResult<+'a> =
+  | @as("fulfilled") Fulfilled({value: 'a}) | @as("rejected") Rejected({reason: exn})
+
+/**
+`allSettled(promises)` runs all promises concurrently and returns promise fulfills when all of the input's promises settle with an array of objects that describe the outcome of each promise. See [`Promise.allSettled`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/allSettled) on MDN.
+
+```rescript
+open Promise
+
+exception TestError(string)
+
+let promises = [resolve(1), resolve(2), reject(TestError("some rejected promise"))]
+
+allSettled(promises)
+->then((results) => {
+  results->Array.forEach((result) => {
+    switch result {
+      | Fulfilled({value: num}) => 
+        Console.log2("Number: ", num)
+      | Rejected({reason}) =>
+        Console.log(reason)
+    }
+  })
+
+  resolve()
+})
+->ignore
+```
+*/
+@scope("Promise")
+@val
+external allSettled: array<t<'a>> => t<array<settledResult<'a>>> = "allSettled"
+
+/**
+`allSettled2((p1, p2))`. Like `allSettled()`, but with a fixed size tuple of 2
+*/
+@scope("Promise")
+@val
+external allSettled2: ((t<'a>, t<'b>)) => t<(settledResult<'a>, settledResult<'b>)> = "allSettled"
+
+/**
+`allSettled3((p1, p2, p3))`. Like `allSettled()`, but with a fixed size tuple of 3
+*/
+@scope("Promise")
+@val
+external allSettled3: ((t<'a>, t<'b>, t<'c>)) => t<(
+  settledResult<'a>,
+  settledResult<'b>,
+  settledResult<'c>,
+)> = "allSettled"
+
+/**
+`allSettled4((p1, p2, p3, p4))`. Like `allSettled()`, but with a fixed size tuple of 4
+*/
+@scope("Promise")
+@val
+external allSettled4: ((t<'a>, t<'b>, t<'c>, t<'d>)) => t<(
+  settledResult<'a>,
+  settledResult<'b>,
+  settledResult<'c>,
+  settledResult<'d>,
+)> = "allSettled"
+
+/**
+`allSettled5((p1, p2, p3, p4, p5))`. Like `allSettled()`, but with a fixed size tuple of 5
+*/
+@scope("Promise")
+@val
+external allSettled5: ((t<'a>, t<'b>, t<'c>, t<'d>, t<'e>)) => t<(
+  settledResult<'a>,
+  settledResult<'b>,
+  settledResult<'c>,
+  settledResult<'d>,
+  settledResult<'e>,
+)> = "allSettled"
+
+/**
+`allSettled6((p1, p2, p4, p5, p6))`. Like `allSettled()`, but with a fixed size tuple of 6
+")*/
+@scope("Promise")
+@val
+external allSettled6: ((t<'a>, t<'b>, t<'c>, t<'d>, t<'e>, t<'f>)) => t<(
+  settledResult<'a>,
+  settledResult<'b>,
+  settledResult<'c>,
+  settledResult<'d>,
+  settledResult<'e>,
+  settledResult<'f>,
+)> = "allSettled"
+
+/**
+`done(p)` is a safe way to ignore a promise. If a value is anything else than a
+promise, it will raise a type error.
+*/
+external done: promise<'a> => unit = "%ignore"
diff --git a/runtime/RegExp.res b/runtime/RegExp.res
new file mode 100644
index 0000000000..9f19af81ab
--- /dev/null
+++ b/runtime/RegExp.res
@@ -0,0 +1,24 @@
+type t = Js.Re.t
+
+module Result = {
+  type t = array<option<string>>
+  @get_index external fullMatch: (t, @as(0) _) => string = ""
+  @send external matches: (t, @as(1) _) => array<string> = "slice"
+  @get external index: t => int = "index"
+  @get external input: t => string = "input"
+}
+
+@new external fromString: string => t = "RegExp"
+@new external fromStringWithFlags: (string, ~flags: string) => t = "RegExp"
+
+@send external test: (t, string) => bool = "test"
+@return(nullable) @send external exec: (t, string) => option<Result.t> = "exec"
+
+@get external lastIndex: t => int = "lastIndex"
+@set external setLastIndex: (t, int) => unit = "lastIndex"
+@get external ignoreCase: t => bool = "ignoreCase"
+@get external global: t => bool = "global"
+@get external multiline: t => bool = "multiline"
+@get external source: t => string = "source"
+@get external sticky: t => bool = "sticky"
+@get external unicode: t => bool = "unicode"
diff --git a/runtime/RegExp.resi b/runtime/RegExp.resi
new file mode 100644
index 0000000000..3e12daef52
--- /dev/null
+++ b/runtime/RegExp.resi
@@ -0,0 +1,290 @@
+/***
+Functions for handling RegExp's in ReScript.
+
+See [`RegExp`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp) on MDN.
+*/
+
+/**
+Type representing an instantiated `RegExp`.
+*/
+type t = Js.Re.t
+
+module Result: {
+  /**
+  Type representing the result of a `RegExp` execution.
+  */
+  type t = array<option<string>>
+
+  /**
+  `fullMatch(regExpResult)` returns the full string that matched in this result.
+
+  ## Examples
+  ```rescript
+  // Match the first two words separated by a space
+  let regexp = RegExp.fromString("(\\w+) (\\w+)")
+
+  switch regexp->RegExp.exec("ReScript is pretty cool, right?") {
+  | None => Console.log("Nope, no match...")
+  | Some(result) => Console.log(result->RegExp.Result.fullMatch) // Prints the full string that matched, "ReScript is"
+  }
+  ```
+  */
+  @get_index
+  external fullMatch: (t, @as(0) _) => string = ""
+
+  /**
+  `matches(regExpResult)` returns all matches for `regExpResult`.
+
+  ## Examples
+  ```rescript
+  // Match the first two words separated by a space
+  let regexp = RegExp.fromString("(\\w+) (\\w+)")
+
+  // This below will log "ReScript" and "is" to the console.
+  switch regexp->RegExp.exec("ReScript is pretty cool, right?") {
+  | None => Console.log("Nope, no match...")
+  | Some(result) => switch result->RegExp.Result.matches {
+    | [firstWord, secondWord] => Console.log2(firstWord, secondWord)
+    | _ => Console.log("Didn't find exactly two words...")
+    }
+  }
+  ```
+  */
+  @send
+  external matches: (t, @as(1) _) => array<string> = "slice"
+  @get external index: t => int = "index"
+
+  /**
+  `input(regExpResult)` returns the full input string that was passed to what produced the `RegExp.Result.t`.
+
+  ## Examples
+  ```rescript
+  // Match the first two words separated by a space
+  let regexp = RegExp.fromString("(\\w+) (\\w+)")
+
+  // This below will log the full input string "ReScript is pretty cool, right?" to the console.
+  switch regexp->RegExp.exec("ReScript is pretty cool, right?") {
+  | None => Console.log("Nope, no match...")
+  | Some(result) => Console.log(result->RegExp.Result.input)
+  }
+  ```
+  */
+  @get
+  external input: t => string = "input"
+}
+
+/**
+`fromString(string)` creates a `RegExp.t` from the provided string. This can then be used to match on strings using `RegExp.exec`.
+
+See [`RegExp`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/RegExp) on MDN.
+
+## Examples
+```rescript
+// Match the first word in a sentence
+let regexp = RegExp.fromString("\\w+")
+
+switch regexp->RegExp.exec("ReScript is pretty cool, right?") {
+| None => Console.log("Nope, no match...")
+| Some(result) => Console.log(result->RegExp.Result.fullMatch) // Prints "ReScript"
+}
+```
+*/
+@new
+external fromString: string => t = "RegExp"
+
+/**
+`fromStringWithFlags(string)` creates a `RegExp.t` from the provided string, using the provided `flags`. This can then be used to match on strings using `RegExp.exec`.
+
+See [`RegExp parameters`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/RegExp#parameters) on MDN.
+
+## Examples
+```rescript
+// Match the first word in a sentence
+let regexp = RegExp.fromStringWithFlags("\\w+", ~flags="g")
+
+switch regexp->RegExp.exec("ReScript is pretty cool, right?") {
+| None => Console.log("Nope, no match...")
+| Some(result) => Console.log(result->RegExp.Result.fullMatch) // Prints "ReScript"
+}
+```
+*/
+@new
+external fromStringWithFlags: (string, ~flags: string) => t = "RegExp"
+
+/**
+`test(regexp, string)` tests whether the provided `regexp` matches on the provided string.
+
+See [`RegExp.test`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/test) on MDN.
+
+## Examples
+```rescript
+// Match the first word in a sentence
+let regexp = RegExp.fromString("\\w+")
+
+if regexp->RegExp.test("ReScript is cool!") {
+  Console.log("Yay, there's a word in there.")
+}
+```
+*/
+@send
+external test: (t, string) => bool = "test"
+
+/**
+`exec(regexp, string)` executes the provided regexp on the provided string, optionally returning a `RegExp.Result.t` if the regexp matches on the string.
+
+See [`RegExp.exec`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/exec) on MDN.
+
+## Examples
+```rescript
+// Match the first word in a sentence
+let regexp = RegExp.fromString("\\w+")
+
+switch regexp->RegExp.exec("ReScript is pretty cool, right?") {
+| None => Console.log("Nope, no match...")
+| Some(result) => Console.log(result->RegExp.Result.fullMatch) // Prints "ReScript"
+}
+```
+*/
+@return(nullable)
+@send
+external exec: (t, string) => option<Result.t> = "exec"
+
+/**
+`lastIndex(regexp)` returns the index the next match will start from.
+
+See [`RegExp.lastIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/lastIndex) on MDN.
+
+## Examples
+```rescript
+// Match the first word in a sentence
+let regexp = RegExp.fromString("\\w+")
+let someStr = "Many words here."
+
+Console.log(regexp->RegExp.lastIndex) // Logs `0` to the console
+
+regexp->RegExp.exec(someStr)->ignore
+
+Console.log(regexp->RegExp.lastIndex) // Logs `4` to the console
+```
+*/
+@get
+external lastIndex: t => int = "lastIndex"
+
+/**
+`setLastIndex(regexp, index)` set the index the next match will start from.
+
+See [`RegExp.lastIndex`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/lastIndex) on MDN.
+
+## Examples
+```rescript
+// Match the first word in a sentence
+let regexp = RegExp.fromString("\\w+")
+let someStr = "Many words here."
+
+regexp->RegExp.setLastIndex(4)
+regexp->RegExp.exec(someStr)->ignore
+
+Console.log(regexp->RegExp.lastIndex) // Logs `10` to the console
+```
+*/
+@set
+external setLastIndex: (t, int) => unit = "lastIndex"
+
+/**
+`ignoreCase(regexp)` returns whether the ignore case (`i`) flag is set on this `RegExp`.
+
+See [`RegExp.ignoreCase`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/ignoreCase) on MDN.
+
+## Examples
+```rescript
+let regexp1 = RegExp.fromStringWithFlags("\\w+", ~flags="g")
+Console.log(regexp1->RegExp.ignoreCase) // Logs `false`, since `i` is not set
+
+let regexp2 = RegExp.fromStringWithFlags("\\w+", ~flags="i")
+Console.log(regexp2->RegExp.ignoreCase) // Logs `true`, since `i` is set
+```
+*/
+@get
+external ignoreCase: t => bool = "ignoreCase"
+
+/**
+`global(regexp)` returns whether the global (`g`) flag is set on this `RegExp`.
+
+See [`RegExp.global`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/global) on MDN.
+
+## Examples
+```rescript
+let regexp1 = RegExp.fromStringWithFlags("\\w+", ~flags="g")
+Console.log(regexp1->RegExp.global) // Logs `true`, since `g` is set
+
+let regexp2 = RegExp.fromStringWithFlags("\\w+", ~flags="i")
+Console.log(regexp2->RegExp.global) // Logs `false`, since `g` is not set
+```
+*/
+@get
+external global: t => bool = "global"
+
+/**
+`multiline(regexp)` returns whether the multiline (`m`) flag is set on this `RegExp`.
+
+See [`RegExp.multiline`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/multiline) on MDN.
+
+## Examples
+```rescript
+let regexp1 = RegExp.fromStringWithFlags("\\w+", ~flags="g")
+Console.log(regexp1->RegExp.multiline) // Logs `false`, since `m` is not set
+
+let regexp2 = RegExp.fromStringWithFlags("\\w+", ~flags="mi")
+Console.log(regexp2->RegExp.multiline) // Logs `true`, since `m` is set
+```
+*/
+@get
+external multiline: t => bool = "multiline"
+
+/**
+`source(regexp)` returns the source text for this `RegExp`, without the two forward slashes (if present), and without any set flags.
+
+See [`RegExp.source`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/source) on MDN.
+
+## Examples
+```rescript
+let regexp = RegExp.fromStringWithFlags("\\w+", ~flags="g")
+Console.log(regexp->RegExp.source) // Logs `\w+`, the source text of the `RegExp`
+```
+*/
+@get
+external source: t => string = "source"
+
+/**
+`sticky(regexp)` returns whether the sticky (`y`) flag is set on this `RegExp`.
+
+See [`RegExp.sticky`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/sticky) on MDN.
+
+## Examples
+```rescript
+let regexp1 = RegExp.fromStringWithFlags("\\w+", ~flags="g")
+Console.log(regexp1->RegExp.unicode) // Logs `false`, since `y` is not set
+
+let regexp2 = RegExp.fromStringWithFlags("\\w+", ~flags="my")
+Console.log(regexp2->RegExp.unicode) // Logs `true`, since `y` is set
+```
+*/
+@get
+external sticky: t => bool = "sticky"
+
+/**
+`unicode(regexp)` returns whether the unicode (`y`) flag is set on this `RegExp`.
+
+See [`RegExp.unicode`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicode) on MDN.
+
+## Examples
+```rescript
+let regexp1 = RegExp.fromStringWithFlags("\\w+", ~flags="g")
+Console.log(regexp1->RegExp.unicode) // Logs `false`, since `u` is not set
+
+let regexp2 = RegExp.fromStringWithFlags("\\w+", ~flags="mu")
+Console.log(regexp2->RegExp.unicode) // Logs `true`, since `u` is set
+```
+*/
+@get
+external unicode: t => bool = "unicode"
diff --git a/runtime/Result.res b/runtime/Result.res
new file mode 100644
index 0000000000..f9307b59f4
--- /dev/null
+++ b/runtime/Result.res
@@ -0,0 +1,97 @@
+/* Copyright (C) 2017 Hongbo Zhang, Authors of ReScript
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+let getExn = x =>
+  switch x {
+  | Ok(x) => x
+  | Error(_) => raise(Not_found)
+  }
+
+let mapOr = (opt, default, f) =>
+  switch opt {
+  | Ok(x) => f(x)
+  | Error(_) => default
+  }
+
+let mapWithDefault = mapOr
+
+let map = (opt, f) =>
+  switch opt {
+  | Ok(x) => Ok(f(x))
+  | Error(_) as result => result
+  }
+
+let flatMap = (opt, f) =>
+  switch opt {
+  | Ok(x) => f(x)
+  | Error(_) as result => result
+  }
+
+let getOr = (opt, default) =>
+  switch opt {
+  | Ok(x) => x
+  | Error(_) => default
+  }
+
+let getWithDefault = getOr
+
+let isOk = x =>
+  switch x {
+  | Ok(_) => true
+  | Error(_) => false
+  }
+
+let isError = x =>
+  switch x {
+  | Ok(_) => false
+  | Error(_) => true
+  }
+
+let equal = (a, b, f) =>
+  switch (a, b) {
+  | (Ok(a), Ok(b)) => f(a, b)
+  | (Error(_), Ok(_))
+  | (Ok(_), Error(_)) => false
+  | (Error(_), Error(_)) => true
+  }
+
+let compare = (a, b, f) =>
+  switch (a, b) {
+  | (Ok(a), Ok(b)) => f(a, b)
+  | (Error(_), Ok(_)) => Ordering.less
+  | (Ok(_), Error(_)) => Ordering.greater
+  | (Error(_), Error(_)) => Ordering.equal
+  }
+
+let forEach = (r, f) =>
+  switch r {
+  | Ok(ok) => f(ok)
+  | Error(_) => ()
+  }
+
+let mapError = (r, f) =>
+  switch r {
+  | Ok(_) as result => result
+  | Error(e) => Error(f(e))
+  }
diff --git a/runtime/Result.resi b/runtime/Result.resi
new file mode 100644
index 0000000000..ac31649e7c
--- /dev/null
+++ b/runtime/Result.resi
@@ -0,0 +1,236 @@
+/* Copyright (C) 2017 Authors of ReScript
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/**
+  Result types are really useful to describe the result of a certain operation
+  without relying on exceptions or `option` types.
+
+  This module gives you useful utilities to create and combine `Result` data.
+*/
+/**
+  The type `Result.t(result, err)` describes a variant of two states:
+  `Ok(someResult)` represents a successful operation, whereby
+  ``Error(someError)` signals an erronous operation.
+
+  In this concrete example, we are defining our own `Result` type to reflect an HTTP like
+  query operation:
+
+  ```res example
+  type responseError = NotAvailable | NotFound
+  type queryResult = result<string, responseError>
+
+  let failQueryUser = (username: string): queryResult => {
+    Error(NotAvailable)
+  }
+```
+*/
+/**
+  `getExn(res)`: when `res` is `Ok(n)`, returns `n` when `res` is `Error(m)`, raise an exception
+
+  ```res example
+  Result.getExn(Result.Ok(42)) == 42
+
+  Result.getExn(Result.Error("Invalid data")) /* raises exception */
+  ```
+*/
+let getExn: result<'a, 'b> => 'a
+
+/**
+`mapOr(res, default, f)`: When res is `Ok(n)`, returns `f(n)`, otherwise `default`.
+
+## Examples
+
+```rescript
+let ok = Ok(42)
+Result.mapOr(ok, 0, (x) => x / 2) == 21
+
+let error = Error("Invalid data")
+Result.mapOr(error, 0, (x) => x / 2) == 0
+```
+*/
+let mapOr: (result<'a, 'c>, 'b, 'a => 'b) => 'b
+
+@deprecated("Use mapOr instead")
+let mapWithDefault: (result<'a, 'c>, 'b, 'a => 'b) => 'b
+
+/**
+`map(res, f)`: When res is `Ok(n)`, returns `Ok(f(n))`. Otherwise returns res
+unchanged. Function `f` takes a value of the same type as `n` and returns an
+ordinary value.
+
+## Examples
+
+```rescript
+let f = (x) => sqrt(Int.toFloat(x))
+
+Result.map(Ok(64), f) == Ok(8.0)
+
+Result.map(Error("Invalid data"), f) == Error("Invalid data")
+```
+*/
+let map: (result<'a, 'c>, 'a => 'b) => result<'b, 'c>
+
+/**
+`flatMap(res, f)`: When res is `Ok(n)`, returns `f(n)`. Otherwise, returns res
+unchanged. Function `f` takes a value of the same type as `n` and returns a
+`Result`.
+
+## Examples
+
+```rescript
+let recip = (x) =>
+  if (x !== 0.0) {
+    Ok(1.0 /. x)
+  } else {
+    Error("Divide by zero")
+  }
+
+Result.flatMap(Ok(2.0), recip) == Ok(0.5)
+
+Result.flatMap(Ok(0.0), recip) == Error("Divide by zero")
+
+Result.flatMap(Error("Already bad"), recip) == Error("Already bad")
+```
+*/
+let flatMap: (result<'a, 'c>, 'a => result<'b, 'c>) => result<'b, 'c>
+
+/**
+`getOr(res, defaultValue)`: If `res` is `Ok(n)`, returns `n`, otherwise `default`
+
+## Examples
+
+```rescript
+Result.getOr(Ok(42), 0) == 42
+
+Result.getOr(Error("Invalid Data"), 0) == 0
+```
+*/
+let getOr: (result<'a, 'b>, 'a) => 'a
+
+@deprecated("Use getOr instead")
+let getWithDefault: (result<'a, 'b>, 'a) => 'a
+
+/**
+`isOk(res)`: Returns `true` if `res` is of the form `Ok(n)`, `false` if it is the `Error(e)` variant.
+*/
+let isOk: result<'a, 'b> => bool
+
+/**
+`isError(res)`: Returns `true` if `res` is of the form `Error(e)`, `false` if it is the `Ok(n)` variant.
+*/
+let isError: result<'a, 'b> => bool
+
+/**
+`equal(res1, res2, f)`: Determine if two `Result` variables are equal with
+respect to an equality function. If `res1` and `res2` are of the form `Ok(n)`
+and `Ok(m)`, return the result of `f(n, m)`. If one of `res1` and `res2` are of
+the form `Error(e)`, return false If both `res1` and `res2` are of the form
+`Error(e)`, return true
+
+## Examples
+
+```rescript
+let good1 = Ok(42)
+
+let good2 = Ok(32)
+
+let bad1 = Error("invalid")
+
+let bad2 = Error("really invalid")
+
+let mod10equal = (a, b) => mod(a, 10) === mod(b, 10)
+
+Result.equal(good1, good2, mod10equal) == true
+
+Result.equal(good1, bad1, mod10equal) == false
+
+Result.equal(bad2, good2, mod10equal) == false
+
+Result.equal(bad1, bad2, mod10equal) == true
+```
+*/
+let equal: (result<'a, 'c>, result<'b, 'd>, ('a, 'b) => bool) => bool
+
+/**
+`compare(res1, res2, f)`: Compare two `Result` variables with respect to a
+comparison function. The comparison function returns -1. if the first variable
+is "less than" the second, 0. if the two variables are equal, and 1. if the first
+is "greater than" the second.
+
+If `res1` and `res2` are of the form `Ok(n)` and `Ok(m)`, return the result of
+`f(n, m)`. If `res1` is of the form `Error(e)` and `res2` of the form `Ok(n)`,
+return -1. (nothing is less than something) If `res1` is of the form `Ok(n)` and
+`res2` of the form `Error(e)`, return 1. (something is greater than nothing) If
+both `res1` and `res2` are of the form `Error(e)`, return 0. (equal)
+
+## Examples
+
+```rescript
+let good1 = Ok(59)
+
+let good2 = Ok(37)
+
+let bad1 = Error("invalid")
+
+let bad2 = Error("really invalid")
+
+let mod10cmp = (a, b) => Int.compare(mod(a, 10), mod(b, 10))
+
+Result.compare(Ok(39), Ok(57), mod10cmp) == 1.
+
+Result.compare(Ok(57), Ok(39), mod10cmp) == (-1.)
+
+Result.compare(Ok(39), Error("y"), mod10cmp) == 1.
+
+Result.compare(Error("x"), Ok(57), mod10cmp) == (-1.)
+
+Result.compare(Error("x"), Error("y"), mod10cmp) == 0.
+```
+*/
+let compare: (result<'a, 'c>, result<'b, 'd>, ('a, 'b) => Ordering.t) => Ordering.t
+
+/**
+`forEach(res, f)` runs the provided function `f` on the `Ok` value. If `res` is `Error`, nothing happens.
+
+## Examples
+
+```rescript
+Result.forEach(Ok(3), Console.log) // Logs "3", returns ()
+Result.forEach(Error("x"), Console.log) // Does nothing, returns ()
+```
+*/
+let forEach: (result<'a, 'b>, 'a => unit) => unit
+
+/**
+`mapError(r, f)` generates a new `result` by applying the function `f` to the `Error` value. If the source is `Ok`, return it as-is.
+
+## Examples
+
+```rescript
+let format = n => `Error code: ${n->Int.toString}`
+Result.mapError(Error(14), format) // Error("Error code: 14")
+Result.mapError(Ok("abc"), format) // Ok("abc")
+```
+*/
+let mapError: (result<'a, 'b>, 'b => 'c) => result<'a, 'c>
diff --git a/runtime/Set.res b/runtime/Set.res
index b547fe31de..00de67d662 100644
--- a/runtime/Set.res
+++ b/runtime/Set.res
@@ -1,4 +1,27 @@
-// FIXME:
-//   This exists for compatibility reason.
-//   Move this into Pervasives or Core
+type t<'a> = Js.Set.t<'a>
 
+@new external make: unit => t<'a> = "Set"
+@new external fromArray: array<'a> => t<'a> = "Set"
+@new external fromIterator: Iterator.t<'a> => t<'a> = "Set"
+
+@get external size: t<'a> => int = "size"
+
+@send external clear: t<'a> => unit = "clear"
+
+@send external add: (t<'a>, 'a) => unit = "add"
+@send external delete: (t<'a>, 'a) => bool = "delete"
+@send external has: (t<'a>, 'a) => bool = "has"
+
+@send external forEach: (t<'a>, 'a => unit) => unit = "forEach"
+
+@send external values: t<'a> => Iterator.t<'a> = "values"
+
+@send external difference: (t<'a>, t<'a>) => t<'a> = "difference"
+@send external intersection: (t<'a>, t<'a>) => t<'a> = "intersection"
+@send external union: (t<'a>, t<'a>) => t<'a> = "union"
+@send external symmetricDifference: (t<'a>, t<'a>) => t<'a> = "symmetricDifference"
+@send external isSubsetOf: (t<'a>, t<'a>) => bool = "isSubsetOf"
+@send external isSupersetOf: (t<'a>, t<'a>) => bool = "isSupersetOf"
+@send external isDisjointFrom: (t<'a>, t<'a>) => bool = "isDisjointFrom"
+
+external toArray: t<'a> => array<'a> = "Array.from"
diff --git a/runtime/Set.resi b/runtime/Set.resi
new file mode 100644
index 0000000000..e1246faef6
--- /dev/null
+++ b/runtime/Set.resi
@@ -0,0 +1,318 @@
+/***
+Bindings to the mutable JavaScript `Set`.
+
+See [`Set`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set) on MDN.
+*/
+
+/**
+Type representing an instance of `Set`.
+*/
+type t<'a> = Js.Set.t<'a>
+
+/**
+Creates a new, mutable JavaScript `Set`. A `Set` is a collection of unique values.
+
+See [`Set`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set) on MDN.
+
+
+
+## Examples
+```rescript
+// You can annotate the type of your set if you want to
+let mySet: Set.t<string> = Set.make()
+
+// Or you can let ReScript infer what's in your Set
+let set = Set.make()
+set->Set.add("Fine name") // Inferred as Set.t<string>
+```
+
+## Alternatives
+A JavaScript `Set` is mutable. If you're looking for an immutable alternative, check out `Belt.Set`.
+*/
+@new
+external make: unit => t<'a> = "Set"
+
+/**
+Turns an array of values into a Set. Meaning only unique values are preserved.
+
+## Examples
+```rescript
+type languages = ReScript | JavaScript | TypeScript
+let languageRank = [ReScript, JavaScript, TypeScript]
+
+let set = Set.fromArray(languageRank) // Set.t<languages>
+
+switch set->Set.has(ReScript) {
+| true => Console.log("Yay, ReScript is in there!")
+| false => Console.log("Uh-oh, something is _terribly_ wrong with this program... abort.")
+}
+```
+*/
+@new
+external fromArray: array<'a> => t<'a> = "Set"
+
+/**
+Turns an iterator into a `Set`.
+
+## Examples
+```rescript
+// Let's pretend we have an interator
+@val external someIterator: Iterator.t<int> = "someIterator"
+
+let set = Set.fromIterator(someIterator) // Set.t<int>
+```
+*/
+@new
+external fromIterator: Iterator.t<'a> => t<'a> = "Set"
+
+/**
+Returns the size, the number of unique values, of the set.
+
+See [`Set.prototype.size`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/size) on MDN.
+
+## Examples
+```rescript
+let set = Set.make()
+
+set->Set.add("someValue")
+set->Set.add("someValue")
+set->Set.add("someValue2")
+
+let size = set->Set.size // 2
+```
+*/
+@get
+external size: t<'a> => int = "size"
+
+/**
+Clears all entries in the set.
+
+See [`Set.clear`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/clear) on MDN.
+
+## Examples
+```rescript
+let set = Set.make()
+
+set->Set.add("someKey")
+set->Set.size // 1
+
+set->Set.clear
+set->Set.size // 0
+```
+*/
+@send
+external clear: t<'a> => unit = "clear"
+
+/**
+Adds a new value to the set.
+
+See [`Set.add`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/add) on MDN.
+
+## Examples
+```rescript
+let set = Set.make()
+set->Set.add("someValue")
+```
+*/
+@send
+external add: (t<'a>, 'a) => unit = "add"
+
+/**
+Deletes the provided `value` from the set. Returns a `bool` for whether the value existed, and was deleted.
+
+See [`Set.delete`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/delete) on MDN.
+
+## Examples
+```rescript
+let set = Set.make()
+set->Set.add("someValue")
+let didDeleteValue = set->Set.delete("someValue")
+Console.log(didDeleteValue) // Logs `true` to the console, becuase the set had the value, so it was successfully deleted
+
+let didDeleteValue = set->Set.delete("someNonExistantKey")
+Console.log(didDeleteValue) // Logs `false` to the console, becuase the value did not exist in the set
+```
+*/
+@send
+external delete: (t<'a>, 'a) => bool = "delete"
+
+/**
+Checks whether the set has a specific value.
+
+See [`Set.has`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/has) on MDN.
+
+## Examples
+```rescript
+let set = Set.make()
+set->Set.add("someValue")
+
+switch set->Set.has("someValue") {
+| false => Console.log("Nope, didn't have it.")
+| true => Console.log("Yay, we have the value!")
+}
+```
+*/
+@send
+external has: (t<'a>, 'a) => bool = "has"
+
+/**
+Iterates through all values of the set.
+
+See [`Set.forEach`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/forEach) on MDN.
+
+## Examples
+```rescript
+let set = Set.make()
+set->Set.add("someValue")
+set->Set.add("someValue2")
+
+set->Set.forEach(value => {
+  Console.log(value)
+})
+```
+*/
+@send
+external forEach: (t<'a>, 'a => unit) => unit = "forEach"
+
+/**
+Returns an iterator that holds all values of the set.
+
+See [`Set.values`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/values) on MDN.
+
+## Examples
+```rescript
+let set = Set.make()
+set->Set.add("someValue")
+set->Set.add("anotherValue")
+
+let values = set->Set.values
+
+// Logs the first value
+Console.log(Iterator.next(values).value)
+
+// You can also turn the iterator into an array.
+// Remember that an iterator consumes values. We'll need a fresh values iterator to get an array of all values, since we consumed a value via `next` above already.
+Console.log(set->Set.values->Iterator.toArray)
+```
+*/
+@send
+external values: t<'a> => Iterator.t<'a> = "values"
+
+/** 
+Returns a new set with the values of the set that are not in the other set.
+
+See [`Set.difference`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/difference) on MDN.
+
+## Examples
+```rescript
+let set1 = Set.fromArray(["apple", "orange", "banana"])
+let set2 = Set.fromArray(["apple", "banana", "pear"])
+set1->Set.difference(set2) // Set.fromArray(["orange"])
+```
+*/
+@send
+external difference: (t<'a>, t<'a>) => t<'a> = "difference"
+
+/**
+Returns a new set with the values containing the values which are in either the set, but not in both.
+
+See [`Set.symmetricDifference`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/symmetricDifference) on MDN.
+
+## Examples
+```rescript
+let set1 = Set.fromArray(["apple", "orange", "banana"])
+let set2 = Set.fromArray(["apple", "banana", "pear"])
+set1->Set.symmetricDifference(set2) // Set.fromArray(["orange", "pear"])
+```
+
+*/
+@send
+external symmetricDifference: (t<'a>, t<'a>) => t<'a> = "symmetricDifference"
+
+/**
+Returns a new set with the values containing the values which are in both the set and the other set.
+
+See [`Set.intersection`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/intersection) on MDN.
+
+## Examples
+```rescript
+let set1 = Set.fromArray(["apple", "orange", "banana"])
+let set2 = Set.fromArray(["apple", "banana", "pear"])
+set1->Set.intersection(set2) // Set.fromArray(["apple", "banana"])
+```
+*/
+@send
+external intersection: (t<'a>, t<'a>) => t<'a> = "intersection"
+
+/**
+Returns a bool indicating if this set has no elements in common with the given set.
+
+See [`Set.isDisjointFrom`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/isDisjointFrom) on MDN.
+
+## Examples
+```rescript
+let set1 = Set.fromArray(["apple", "orange", "banana"])
+let set2 = Set.fromArray(["kiwi", "melon", "pear"])
+set1->Set.isDisjointFrom(set2) // true
+```
+*/
+@send
+external isDisjointFrom: (t<'a>, t<'a>) => bool = "isDisjointFrom"
+
+/**
+Returns a bool indicating if the all values in the set are in the given set.
+
+See [`Set.isSubsetOf`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/isSubsetOf) on MDN.
+
+## Examples
+```rescript
+let set1 = Set.fromArray(["apple", "banana"])
+let set2 = Set.fromArray(["apple", "banana", "pear"])
+set1->Set.isSubsetOf(set2) // true
+```
+ */
+@send
+external isSubsetOf: (t<'a>, t<'a>) => bool = "isSubsetOf"
+
+/**
+Returns a bool indicating if the all values in the given set are in the set.
+
+See [`Set.isSupersetOf`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/isSupersetOf) on MDN.
+
+## Examples
+```rescript
+let set1 = Set.fromArray(["apple", "banana", "pear"])
+let set2 = Set.fromArray(["apple", "banana"])
+set1->Set.isSupersetOf(set2) // true
+ ```
+*/
+@send
+external isSupersetOf: (t<'a>, t<'a>) => bool = "isSupersetOf"
+
+/**
+ Returns a new set with the values of the set that are in both the set and the other set.
+
+See [`Set.union`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/union) on MDN.
+
+## Examples
+```rescript
+let set1 = Set.fromArray(["apple", "orange", "banana"])
+let set2 = Set.fromArray(["apple", "banana", "pear"])
+set1->Set.union(set2) // Set.fromArray(["apple", "orange", "banana", "pear"])
+```
+*/
+@send
+external union: (t<'a>, t<'a>) => t<'a> = "union"
+
+/**
+`toArray(set)` returns an array of all values of the set.
+
+See [`Array.from`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/from) on MDN.
+
+## Examples
+```rescript
+let set = Set.fromArray(["apple", "orange", "apple", "banana"])
+set->Set.toArray // ["apple", "orange", "banana"]
+```
+*/
+external toArray: t<'a> => array<'a> = "Array.from"
diff --git a/runtime/String.res b/runtime/String.res
index 3613f1dde4..cab2376a60 100644
--- a/runtime/String.res
+++ b/runtime/String.res
@@ -1,223 +1,133 @@
-// FIXME:
-//   This exists for compatibility reason.
-//   Move this into Pervasives or Core
+@val external make: 'a => string = "String"
 
-// Below is all deprecated and should be removed in v13
+@val external fromCharCode: int => string = "String.fromCharCode"
+@variadic @val external fromCharCodeMany: array<int> => string = "String.fromCharCode"
 
-type t = string
+@val external fromCodePoint: int => string = "String.fromCodePoint"
+@variadic @val external fromCodePointMany: array<int> => string = "String.fromCodePoint"
 
-module B = {
-  include Array
+external equal: (string, string) => bool = "%equal"
 
-  let uppercase_ascii = bytes => map(Char.uppercase_ascii, bytes)
-  let lowercase_ascii = bytes => map(Char.lowercase_ascii, bytes)
+external compare: (string, string) => Ordering.t = "%compare"
 
-  let apply1 = (f, bytes) =>
-    if length(bytes) == 0 {
-      bytes
-    } else {
-      let r = copy(bytes)
-      unsafe_set(r, 0, f(unsafe_get(bytes, 0)))
-      r
-    }
-  let capitalize_ascii = bytes => apply1(Char.uppercase_ascii, bytes)
-  let uncapitalize_ascii = bytes => apply1(Char.lowercase_ascii, bytes)
+@get external length: string => int = "length"
+@get_index external get: (string, int) => option<string> = ""
+@get_index external getUnsafe: (string, int) => string = ""
+@send external charAt: (string, int) => string = "charAt"
 
-  let escaped = bytes => map(Char.escaped, bytes)
-}
+@send external charCodeAt: (string, int) => float = "charCodeAt"
+@send external codePointAt: (string, int) => option<int> = "codePointAt"
 
-@send external join: (array<string>, string) => string = "join"
+@send external concat: (string, string) => string = "concat"
+@variadic @send external concatMany: (string, array<string>) => string = "concat"
 
-let concat = (sep: string, xs: list<string>) => xs->Array.of_list->join(sep)
+@send external endsWith: (string, string) => bool = "endsWith"
+@send external endsWithFrom: (string, string, int) => bool = "endsWith"
 
-external length: string => int = "%string_length"
+@send external includes: (string, string) => bool = "includes"
+@send external includesFrom: (string, string, int) => bool = "includes"
 
-@send external get: (string, int) => char = "codePointAt"
-
-@send external unsafe_get: (string, int) => char = "codePointAt"
-
-@scope("Array") external bos: string => array<string> = "from"
-let bos = str => B.map(str => str->unsafe_get(0), str->bos)
-
-@scope("String") @variadic
-external bts: array<char> => string = "fromCodePoint"
-
-let make = (len, ch) => Primitive_string_extern.fromChar(ch)->Primitive_string_extern.repeat(len)
-
-let init = (len, f) => Array.init(len, i => Primitive_string_extern.fromChar(f(i)))->join("")
-
-let sub = (s, ofs, len) => bts(B.sub(bos(s), ofs, len))
-
-external compare: (t, t) => int = "%compare"
-
-external equal: (t, t) => bool = "%equal"
-
-let iter = (f, s) =>
-  for i in 0 to length(s) - 1 {
-    f(unsafe_get(s, i))
-  }
-
-let iteri = (f, s) =>
-  for i in 0 to length(s) - 1 {
-    f(i, unsafe_get(s, i))
+@send external indexOf: (string, string) => int = "indexOf"
+let indexOfOpt = (s, search) =>
+  switch indexOf(s, search) {
+  | -1 => None
+  | index => Some(index)
   }
+@send external indexOfFrom: (string, string, int) => int = "indexOf"
 
-let map = (f, s) => bts(B.map(f, bos(s)))
-let mapi = (f, s) => bts(B.mapi(f, bos(s)))
-
-@send external trim: string => string = "trim"
-
-let escaped = s => {
-  let rec needs_escape = i =>
-    if i >= length(s) {
-      false
-    } else {
-      switch unsafe_get(s, i) {
-      | '"' | '\\' | '\n' | '\t' | '\r' | '\b' => true
-      | ' ' .. '~' => needs_escape(i + 1)
-      | _ => true
-      }
-    }
-
-  if needs_escape(0) {
-    join(B.escaped(bos(s)), "")
-  } else {
-    s
+@send external lastIndexOf: (string, string) => int = "lastIndexOf"
+let lastIndexOfOpt = (s, search) =>
+  switch lastIndexOf(s, search) {
+  | -1 => None
+  | index => Some(index)
   }
-}
-
-/* duplicated in bytes.ml */
-let rec index_rec = (s, lim, i, c) =>
-  if i >= lim {
-    raise(Not_found)
-  } else if unsafe_get(s, i) == c {
-    i
-  } else {
-    index_rec(s, lim, i + 1, c)
+@send external lastIndexOfFrom: (string, string, int) => int = "lastIndexOf"
+
+@return(nullable) @send
+external match: (string, RegExp.t) => option<RegExp.Result.t> = "match"
+
+type normalizeForm = [#NFC | #NFD | #NFKC | #NFKD]
+@send external normalize: string => string = "normalize"
+@send external normalizeByForm: (string, normalizeForm) => string = "normalize"
+
+@send external repeat: (string, int) => string = "repeat"
+
+@send external replace: (string, string, string) => string = "replace"
+@send external replaceRegExp: (string, RegExp.t, string) => string = "replace"
+@send external replaceAll: (string, string, string) => string = "replaceAll"
+@send external replaceAllRegExp: (string, RegExp.t, string) => string = "replaceAll"
+
+@send
+external unsafeReplaceRegExpBy0: (
+  string,
+  RegExp.t,
+  (~match: string, ~offset: int, ~input: string) => string,
+) => string = "replace"
+
+@send
+external unsafeReplaceRegExpBy1: (
+  string,
+  RegExp.t,
+  (~match: string, ~group1: string, ~offset: int, ~input: string) => string,
+) => string = "replace"
+
+@send
+external unsafeReplaceRegExpBy2: (
+  string,
+  RegExp.t,
+  (~match: string, ~group1: string, ~group2: string, ~offset: int, ~input: string) => string,
+) => string = "replace"
+
+@send
+external unsafeReplaceRegExpBy3: (
+  string,
+  RegExp.t,
+  (
+    ~match: string,
+    ~group1: string,
+    ~group2: string,
+    ~group3: string,
+    ~offset: int,
+    ~input: string,
+  ) => string,
+) => string = "replace"
+
+@send external search: (string, RegExp.t) => int = "search"
+let searchOpt = (s, re) =>
+  switch search(s, re) {
+  | -1 => None
+  | index => Some(index)
   }
 
-/* duplicated in bytes.ml */
-let index = (s, c) => index_rec(s, length(s), 0, c)
-
-/* duplicated in bytes.ml */
-let rec index_rec_opt = (s, lim, i, c) =>
-  if i >= lim {
-    None
-  } else if unsafe_get(s, i) == c {
-    Some(i)
-  } else {
-    index_rec_opt(s, lim, i + 1, c)
-  }
+@send external slice: (string, ~start: int, ~end: int) => string = "slice"
+@send external sliceToEnd: (string, ~start: int) => string = "slice"
 
-/* duplicated in bytes.ml */
-let index_opt = (s, c) => index_rec_opt(s, length(s), 0, c)
+@send external split: (string, string) => array<string> = "split"
+@send external splitAtMost: (string, string, ~limit: int) => array<string> = "split"
+@send external splitByRegExp: (string, RegExp.t) => array<option<string>> = "split"
+@send
+external splitByRegExpAtMost: (string, RegExp.t, ~limit: int) => array<option<string>> = "split"
 
-/* duplicated in bytes.ml */
-let index_from = (s, i, c) => {
-  let l = length(s)
-  if i < 0 || i > l {
-    invalid_arg("String.index_from / Bytes.index_from")
-  } else {
-    index_rec(s, l, i, c)
-  }
-}
-
-/* duplicated in bytes.ml */
-let index_from_opt = (s, i, c) => {
-  let l = length(s)
-  if i < 0 || i > l {
-    invalid_arg("String.index_from_opt / Bytes.index_from_opt")
-  } else {
-    index_rec_opt(s, l, i, c)
-  }
-}
-
-/* duplicated in bytes.ml */
-let rec rindex_rec = (s, i, c) =>
-  if i < 0 {
-    raise(Not_found)
-  } else if unsafe_get(s, i) == c {
-    i
-  } else {
-    rindex_rec(s, i - 1, c)
-  }
+@send external startsWith: (string, string) => bool = "startsWith"
+@send external startsWithFrom: (string, string, int) => bool = "startsWith"
 
-/* duplicated in bytes.ml */
-let rindex = (s, c) => rindex_rec(s, length(s) - 1, c)
+@send external substring: (string, ~start: int, ~end: int) => string = "substring"
+@send external substringToEnd: (string, ~start: int) => string = "substring"
 
-/* duplicated in bytes.ml */
-let rindex_from = (s, i, c) =>
-  if i < -1 || i >= length(s) {
-    invalid_arg("String.rindex_from / Bytes.rindex_from")
-  } else {
-    rindex_rec(s, i, c)
-  }
+@send external toLowerCase: string => string = "toLowerCase"
+@send external toLocaleLowerCase: string => string = "toLocaleLowerCase"
+@send external toUpperCase: string => string = "toUpperCase"
+@send external toLocaleUpperCase: string => string = "toLocaleUpperCase"
 
-/* duplicated in bytes.ml */
-let rec rindex_rec_opt = (s, i, c) =>
-  if i < 0 {
-    None
-  } else if unsafe_get(s, i) == c {
-    Some(i)
-  } else {
-    rindex_rec_opt(s, i - 1, c)
-  }
-
-/* duplicated in bytes.ml */
-let rindex_opt = (s, c) => rindex_rec_opt(s, length(s) - 1, c)
+@send external trim: string => string = "trim"
+@send external trimStart: string => string = "trimStart"
+@send external trimEnd: string => string = "trimEnd"
 
-/* duplicated in bytes.ml */
-let rindex_from_opt = (s, i, c) =>
-  if i < -1 || i >= length(s) {
-    invalid_arg("String.rindex_from_opt / Bytes.rindex_from_opt")
-  } else {
-    rindex_rec_opt(s, i, c)
-  }
+@send external padStart: (string, int, string) => string = "padStart"
+@send external padEnd: (string, int, string) => string = "padEnd"
 
-/* duplicated in bytes.ml */
-let contains_from = (s, i, c) => {
-  let l = length(s)
-  if i < 0 || i > l {
-    invalid_arg("String.contains_from / Bytes.contains_from")
-  } else {
-    try {
-      ignore(index_rec(s, l, i, c))
-      true
-    } catch {
-    | Not_found => false
-    }
-  }
-}
-
-/* duplicated in bytes.ml */
-let contains = (s, c) => contains_from(s, 0, c)
-
-/* duplicated in bytes.ml */
-let rcontains_from = (s, i, c) =>
-  if i < 0 || i >= length(s) {
-    invalid_arg("String.rcontains_from / Bytes.rcontains_from")
-  } else {
-    try {
-      ignore(rindex_rec(s, i, c))
-      true
-    } catch {
-    | Not_found => false
-    }
-  }
+@get_index external getSymbol: (string, Symbol.t) => option<'a> = ""
+@get_index external getSymbolUnsafe: (string, Symbol.t) => 'a = ""
+@set_index external setSymbol: (string, Symbol.t, 'a) => unit = ""
 
-let uppercase_ascii = s => bts(B.uppercase_ascii(bos(s)))
-let lowercase_ascii = s => bts(B.lowercase_ascii(bos(s)))
-let capitalize_ascii = s => bts(B.capitalize_ascii(bos(s)))
-let uncapitalize_ascii = s => bts(B.uncapitalize_ascii(bos(s)))
-
-let split_on_char = (sep, s) => {
-  let r = ref(list{})
-  let j = ref(length(s))
-  for i in length(s) - 1 downto 0 {
-    if unsafe_get(s, i) == sep {
-      r := list{sub(s, i + 1, j.contents - i - 1), ...r.contents}
-      j := i
-    }
-  }
-  list{sub(s, 0, j.contents), ...r.contents}
-}
+@send external localeCompare: (string, string) => float = "localeCompare"
diff --git a/runtime/String.resi b/runtime/String.resi
index a5bc660235..c9121179fb 100644
--- a/runtime/String.resi
+++ b/runtime/String.resi
@@ -1,250 +1,1025 @@
-// FIXME:
-//   This exists for compatibility reason.
-//   Move this into Pervasives or Core
-
-// Below is all deprecated and should be removed in v13
-
-/** Return the length (number of characters) of the given string. */
-@deprecated("Use Core instead. This will be removed in v13")
-external length: string => int = "%string_length"
-
-/** [String.get s n] returns the character at index [n] in string [s].
-   You can also write [s.[n]] instead of [String.get s n].
-
-   Raise [Invalid_argument] if [n] not a valid index in [s]. */
-@deprecated("Use Core instead. This will be removed in v13")
-@send
-external get: (string, int) => char = "codePointAt"
-
-/** [String.make n c] returns a fresh string of length [n],
-   filled with the character [c]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let make: (int, char) => string
-
-/** [String.init n f] returns a string of length [n], with character
-    [i] initialized to the result of [f i] (called in increasing
-    index order).
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let init: (int, int => char) => string
-
-/** [String.sub s start len] returns a fresh string of length [len],
-   containing the substring of [s] that starts at position [start] and
-   has length [len].
-
-   Raise [Invalid_argument] if [start] and [len] do not
-   designate a valid substring of [s]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let sub: (string, int, int) => string
-
-/** [String.concat sep sl] concatenates the list of strings [sl],
-    inserting the separator string [sep] between each.
-
-    Raise [Invalid_argument] if the result is longer than
-    {!Sys.max_string_length} bytes. */
-@deprecated("Use Core instead. This will be removed in v13")
-let concat: (string, list<string>) => string
-
-/** [String.iter f s] applies function [f] in turn to all
-   the characters of [s].  It is equivalent to
-   [f s.[0]; f s.[1]; ...; f s.[String.length s - 1]; ()]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let iter: (char => unit, string) => unit
-
-/** Same as {!String.iter}, but the
-   function is applied to the index of the element as first argument
-   (counting from 0), and the character itself as second argument.
-   @since 4.00.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let iteri: ((int, char) => unit, string) => unit
-
-/** [String.map f s] applies function [f] in turn to all the
-    characters of [s] (in increasing index order) and stores the
-    results in a new string that is returned.
-    @since 4.00.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let map: (char => char, string) => string
-
-/** [String.mapi f s] calls [f] with each character of [s] and its
-    index (in increasing index order) and stores the results in a new
-    string that is returned.
-    @since 4.02.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let mapi: ((int, char) => char, string) => string
-
-/** Return a copy of the argument, without leading and trailing
-   whitespace.  The characters regarded as whitespace are: [' '],
-   ['\x0c'], ['\n'], ['\r'], and ['\t'].  If there is neither leading nor
-   trailing whitespace character in the argument, return the original
-   string itself, not a copy.
-   @since 4.00.0 */
-@deprecated("Use Core instead. This will be removed in v13")
+/* Copyright (C) 2015-2016 Bloomberg Finance L.P.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition to the permissions granted to you by the LGPL, you may combine
+ * or link a "work that uses the Library" with a publicly distributed version
+ * of this file to produce a combined library or application, then distribute
+ * that combined work under the terms of your choosing, with no requirement
+ * to comply with the obligations normally placed on you by section 4 of the
+ * LGPL version 3 (or the corresponding section of a later version of the LGPL
+ * should you choose to use a later version).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/***
+Functions for interacting with JavaScript strings.
+See: [`String`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String).
+*/
+
+/**
+`make(value)` converts the given value to a `string`.
+
+## Examples
+
+```rescript
+String.make(3.5) == "3.5"
+String.make([1, 2, 3]) == "1,2,3"
+```
+*/
+@val
+external make: 'a => string = "String"
+
+/**
+`fromCharCode(n)` creates a `string` containing the character corresponding to
+that number, `n` ranges from 0 to 65535. If out of range, the lower 16 bits of
+the value are used. Thus, `fromCharCode(0x1F63A)` gives the same result as
+`fromCharCode(0xF63A)`.
+See [`String.fromCharCode`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/fromCharCode) on MDN.
+
+## Examples
+
+```rescript
+String.fromCharCode(65) == "A"
+String.fromCharCode(0x3c8) == `ψ`
+String.fromCharCode(0xd55c) == `한`
+String.fromCharCode(-64568) == `ψ`
+```
+*/
+@val
+external fromCharCode: int => string = "String.fromCharCode"
+
+/**
+`fromCharCodeMany([n1, n2, n3])` creates a `string` from the characters
+corresponding to the given numbers, using the same rules as `fromCharCode`.
+See [`String.fromCharCode`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/fromCharCode) on MDN.
+
+## Examples
+
+```rescript
+String.fromCharCodeMany([189, 43, 190, 61]) == "½+¾="
+String.fromCharCodeMany([65, 66, 67]) == "ABC"
+```
+*/
+@variadic
+@val
+external fromCharCodeMany: array<int> => string = "String.fromCharCode"
+
+/**
+`fromCodePoint(n)` creates a `string` containing the character corresponding to
+that numeric code point.
+See [`String.fromCodePoint`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/fromCodePoint) on MDN.
+
+## Examples
+
+```rescript
+String.fromCodePoint(65) == "A"
+String.fromCodePoint(0x3c8) == `ψ`
+String.fromCodePoint(0xd55c) == `한`
+String.fromCodePoint(0x1f63a) == `😺`
+```
+
+## Exceptions
+
+- `RangeError`: If the number is not a valid code point, like `fromCharCode(-5)`.
+*/
+@val
+external fromCodePoint: int => string = "String.fromCodePoint"
+
+/**
+`fromCodePointMany([n1, n2, n3])` creates a `string` from the characters
+corresponding to the given code point numbers, using the same rules as
+`fromCodePoint`.
+See [`String.fromCodePoint`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/fromCodePoint) on MDN.
+
+## Examples
+
+```rescript
+String.fromCodePointMany([0xd55c, 0xae00, 0x1f63a]) == `한글😺`
+```
+
+## Exceptions
+
+- `RangeError`: If one of the number is not a valid code point, like
+`fromCharCode([1, -5])`.
+
+*/
+@variadic
+@val
+external fromCodePointMany: array<int> => string = "String.fromCodePoint"
+
+external equal: (string, string) => bool = "%equal"
+
+external compare: (string, string) => Ordering.t = "%compare"
+
+/**
+`length(str)` returns the length of the given `string`.
+See [`String.length`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/length) on MDN.
+
+## Examples
+
+```rescript
+String.length("abcd") == 4
+```
+*/
+@get
+external length: string => int = "length"
+
+/**
+`get(str, index)` returns an `option<string>` at the given `index` number. If
+`index` is out of range, this function returns `None`.
+
+## Examples
+
+```rescript
+String.get("ReScript", 0) == Some("R")
+String.get("Hello", 4) == Some("o")
+String.get(`JS`, 4) == None
+```
+*/
+@get_index
+external get: (string, int) => option<string> = ""
+
+/**
+`getUnsafe(str, index)` returns an `string` at the given `index` number.
+
+This is _unsafe_, meaning it will return `undefined` value if `index` does not exist in `string`.
+
+Use `String.getUnsafe` only when you are sure the `index` exists.
+## Examples
+
+```rescript
+String.getUnsafe("ReScript", 0) == "R"
+String.getUnsafe("Hello", 4) == "o"
+```
+*/
+@get_index
+external getUnsafe: (string, int) => string = ""
+
+/**
+`charAt(str, index)` gets the character at `index` within string `str`. If
+`index` is negative or greater than the length of `str`, it returns the empty
+string. If the string contains characters outside the range \u0000-\uffff, it
+will return the first 16-bit value at that position in the string.
+See [`String.charAt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/charAt) on MDN.
+
+## Examples
+
+```rescript
+String.charAt("ReScript", 0) == "R"
+String.charAt("Hello", 12) == ""
+String.charAt(`JS`, 5) == ""
+```
+*/
+@send
+external charAt: (string, int) => string = "charAt"
+
+/**
+`charCodeAt(str, index)` returns the character code at position `index` in
+string `str` the result is in the range 0-65535, unlike `codePointAt`, so it
+will not work correctly for characters with code points greater than or equal
+to 0x10000. The return type is `float` because this function returns NaN if
+`index` is less than zero or greater than the length of the string.
+See [`String.charCodeAt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/charCodeAt) on MDN.
+
+## Examples
+
+```rescript
+String.charCodeAt(`😺`, 0) == 0xd83d->Int.toFloat
+String.codePointAt(`😺`, 0) == Some(0x1f63a)
+```
+*/
+@send
+external charCodeAt: (string, int) => float = "charCodeAt"
+
+/**
+`codePointAt(str, index)` returns the code point at position `index` within
+string `str` as a `Some(value)`. The return value handles code points greater
+than or equal to 0x10000. If there is no code point at the given position, the
+function returns `None`.
+See [`String.codePointAt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/codePointAt) on MDN.
+
+## Examples
+
+```rescript
+String.codePointAt(`¿😺?`, 1) == Some(0x1f63a)
+String.codePointAt("abc", 5) == None
+```
+*/
+@send
+external codePointAt: (string, int) => option<int> = "codePointAt"
+
+/**
+`concat(original, append)` returns a new `string` with `append` added after
+`original`.
+See [`String.concat`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/concat) on MDN.
+
+## Examples
+
+```rescript
+String.concat("cow", "bell") == "cowbell"
+String.concat("Re", "Script") == "ReScript"
+```
+*/
+@send
+external concat: (string, string) => string = "concat"
+
+/**
+`concatMany(original, arr)` returns a new `string` consisting of each item of an
+array of strings added to the `original` string.
+See [`String.concat`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/concat) on MDN.
+
+## Examples
+
+```rescript
+String.concatMany("1st", ["2nd", "3rd", "4th"]) == "1st2nd3rd4th"
+```
+*/
+@variadic
+@send
+external concatMany: (string, array<string>) => string = "concat"
+
+/**
+`endsWith(str, substr)` returns `true` if the `str` ends with `substr`, `false`
+otherwise.
+See [`String.endsWith`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith) on MDN.
+
+## Examples
+
+```rescript
+String.endsWith("BuckleScript", "Script") == true
+String.endsWith("BuckleShoes", "Script") == false
+```
+*/
+@send
+external endsWith: (string, string) => bool = "endsWith"
+
+// NOTE: Honestly, this should have been named endsWithAt, but oh well
+/**
+`endsWithFrom(str, ending, len)` returns `true` if the first len characters of
+`str` end with `ending`, `false` otherwise. If `len` is greater than or equal
+to the length of `str`, then it works like `endsWith`.
+See [`String.endsWith`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith) on MDN.
+
+## Examples
+
+```rescript
+String.endsWithFrom("abcd", "cd", 4) == true
+String.endsWithFrom("abcde", "cd", 3) == false
+String.endsWithFrom("abcde", "cde", 99) == true
+String.endsWithFrom("example.dat", "ple", 7) == true
+```
+*/
+@send
+external endsWithFrom: (string, string, int) => bool = "endsWith"
+
+/**
+`includes(str, searchValue)` returns `true` if `searchValue` is found anywhere
+within `str`, `false` otherwise.
+See [`String.includes`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes) on MDN.
+
+## Examples
+
+```rescript
+String.includes("programmer", "gram") == true
+String.includes("programmer", "er") == true
+String.includes("programmer", "pro") == true
+String.includes("programmer.dat", "xyz") == false
+```
+*/
+@send
+external includes: (string, string) => bool = "includes"
+
+/**
+`includesFrom(str, searchValue, start)` returns `true` if `searchValue` is found
+anywhere within `str` starting at character number `start` (where 0 is the
+first character), `false` otherwise.
+See [`String.includes`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes) on MDN.
+
+## Examples
+
+```rescript
+String.includesFrom("programmer", "gram", 1) == true
+String.includesFrom("programmer", "gram", 4) == false
+String.includesFrom(`대한민국`, `한`, 1) == true
+```
+*/
+@send
+external includesFrom: (string, string, int) => bool = "includes"
+
+/**
+`indexOf(str, searchValue)` returns the position at which `searchValue` was
+first found within `str`, or `-1` if `searchValue` is not in `str`.
+See [`String.indexOf`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf) on MDN.
+
+## Examples
+
+```rescript
+String.indexOf("bookseller", "ok") == 2
+String.indexOf("bookseller", "sell") == 4
+String.indexOf("beekeeper", "ee") == 1
+String.indexOf("bookseller", "xyz") == -1
+```
+*/
+@send
+external indexOf: (string, string) => int = "indexOf"
+
+/**
+`indexOfOpt(str, searchValue)`. Like `indexOf`, but return an `option<int>`.
+
+## Examples
+
+```rescript
+String.indexOfOpt("bookseller", "ok") == Some(2)
+String.indexOfOpt("bookseller", "xyz") == None
+```
+*/
+let indexOfOpt: (string, string) => option<int>
+
+/**
+`indexOfFrom(str, searchValue, start)` returns the position at which
+`searchValue` was found within `str` starting at character position `start`, or
+`-1` if `searchValue` is not found in that portion of `str`. The return value is
+relative to the beginning of the string, no matter where the search started
+from.
+See [`String.indexOf`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf) on MDN.
+
+## Examples
+
+```rescript
+String.indexOfFrom("bookseller", "ok", 1) == 2
+String.indexOfFrom("bookseller", "sell", 2) == 4
+String.indexOfFrom("bookseller", "sell", 5) == -1
+```
+*/
+@send
+external indexOfFrom: (string, string, int) => int = "indexOf"
+
+/**
+`lastIndexOf(str, searchValue)` returns the position of the last occurrence of
+`searchValue` within `str`, searching backwards from the end of the string.
+Returns `-1` if `searchValue` is not in `str`. The return value is always
+relative to the beginning of the string.
+See [`String.lastIndexOf`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/lastIndexOf) on MDN.
+
+## Examples
+
+```rescript
+String.lastIndexOf("bookseller", "ok") == 2
+String.lastIndexOf("beekeeper", "ee") == 4
+String.lastIndexOf("abcdefg", "xyz") == -1
+```
+*/
+@send
+external lastIndexOf: (string, string) => int = "lastIndexOf"
+
+/**
+`lastIndexOfOpt(str, searchValue)`. Like `lastIndexOfOpt`, but return an
+`option<int>`.
+
+## Examples
+
+```rescript
+String.lastIndexOfOpt("bookseller", "ok") == Some(2)
+String.lastIndexOfOpt("beekeeper", "ee") == Some(4)
+String.lastIndexOfOpt("abcdefg", "xyz") == None
+```
+*/
+let lastIndexOfOpt: (string, string) => option<int>
+
+/**
+`lastIndexOfFrom(str, searchValue, start)` returns the position of the last
+occurrence of `searchValue` within `str`, searching backwards from the given
+start position. Returns `-1` if `searchValue` is not in `str`. The return value
+is always relative to the beginning of the string.
+See [`String.lastIndexOf`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/lastIndexOf) on MDN.
+
+## Examples
+
+```rescript
+String.lastIndexOfFrom("bookseller", "ok", 6) == 2
+String.lastIndexOfFrom("beekeeper", "ee", 8) == 4
+String.lastIndexOfFrom("beekeeper", "ee", 3) == 1
+String.lastIndexOfFrom("abcdefg", "xyz", 4) == -1
+```
+*/
+@send
+external lastIndexOfFrom: (string, string, int) => int = "lastIndexOf"
+
+/**
+`match(str, regexp)` matches a `string` against the given `regexp`. If there is
+no match, it returns `None`. For regular expressions without the g modifier, if
+there is a match, the return value is `Some(array)` where the array contains:
+- The entire matched string
+- Any capture groups if the regexp had parentheses
+For regular expressions with the g modifier, a matched expression returns
+`Some(array)` with all the matched substrings and no capture groups.
+See [`String.match`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/match) on MDN.
+
+## Examples
+
+```rescript
+String.match("The better bats", %re("/b[aeiou]t/")) == Some([Some("bet")])
+String.match("The better bats", %re("/b[aeiou]t/g")) == Some([Some("bet"), Some("bat")])
+String.match("Today is 2018-04-05.", %re("/(\d+)-(\d+)-(\d+)/")) ==
+  Some([Some("2018-04-05"), Some("2018"), Some("04"), Some("05")])
+String.match("The optional example", %re("/(foo)?(example)/")) == Some([Some("example"), None, Some("example")])
+String.match("The large container.", %re("/b[aeiou]g/")) == None
+```
+*/
+@return(nullable)
+@send
+external match: (string, RegExp.t) => option<RegExp.Result.t> = "match"
+
+/**
+`normalize(str)` returns the normalized Unicode string using Normalization Form
+Canonical (NFC) Composition. Consider the character ã, which can be represented
+as the single codepoint \u00e3 or the combination of a lower case letter A
+\u0061 and a combining tilde \u0303. Normalization ensures that both can be
+stored in an equivalent binary representation.
+See [`String.normalize`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/normalize) on MDN.
+See also [Unicode technical report #15](https://unicode.org/reports/tr15/) for details.
+
+## Examples
+
+```rescript
+let string1 = "\uFB00"
+let string2 = "\u0066\u0066"
+Console.log(string1 === string2) // false
+
+let normalizeString1 = String.normalize(string1)
+let normalizeString2 = String.normalize(string2)
+assert(normalizeString1 === normalizeString2)
+```
+*/
+@send
+external normalize: string => string = "normalize"
+
+/**
+`normalizeByForm(str, form)` returns the normalized Unicode string using the
+specified form of normalization, which may be one of:
+- "NFC" — Normalization Form Canonical Composition.
+- "NFD" — Normalization Form Canonical Decomposition.
+- "NFKC" — Normalization Form Compatibility Composition.
+- "NFKD" — Normalization Form Compatibility Decomposition.
+See [`String.normalize`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/normalize) on MDN.
+See also [Unicode technical report #15](https://unicode.org/reports/tr15/) for
+details.
+
+## Examples
+
+```rescript
+let string1 = "\uFB00"
+let string2 = "\u0066\u0066"
+Console.log(string1 == string2) // false
+
+let normalizeString1 = String.normalizeByForm(string1, #NFKD)
+let normalizeString2 = String.normalizeByForm(string2, #NFKD)
+Console.log(normalizeString1 == normalizeString2) // true
+```
+*/
+type normalizeForm = [#NFC | #NFD | #NFKC | #NFKD]
+@send
+external normalizeByForm: (string, normalizeForm) => string = "normalize"
+
+/**
+`repeat(str, n)` returns a `string` that consists of `n` repetitions of `str`.
+See [`String.repeat`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat) on MDN.
+
+## Examples
+
+```rescript
+String.repeat("ha", 3) == "hahaha"
+String.repeat("empty", 0) == ""
+```
+
+## Exceptions
+
+- `RangeError`: if `n` is negative.
+*/
+@send
+external repeat: (string, int) => string = "repeat"
+
+/**
+`replace(str, substr, newSubstr)` returns a new `string` which is
+identical to `str` except with the first matching instance of `substr` replaced
+by `newSubstr`. `substr` is treated as a verbatim string to match, not a
+regular expression.
+See [`String.replace`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace) on MDN.
+
+## Examples
+
+```rescript
+String.replace("old string", "old", "new") == "new string"
+String.replace("the cat and the dog", "the", "this") == "this cat and the dog"
+```
+*/
+@send
+external replace: (string, string, string) => string = "replace"
+
+/**
+`replaceRegExp(str, regex, replacement)` returns a new `string` where
+occurrences matching regex have been replaced by `replacement`.
+See [`String.replace`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace) on MDN.
+
+## Examples
+
+```rescript
+String.replaceRegExp("vowels be gone", %re("/[aeiou]/g"), "x") == "vxwxls bx gxnx"
+String.replaceRegExp("Juan Fulano", %re("/(\w+) (\w+)/"), "$2, $1") == "Fulano, Juan"
+```
+*/
+@send
+external replaceRegExp: (string, RegExp.t, string) => string = "replace"
+
+/**
+`replaceAll(str, substr, newSubstr)` returns a new `string` which is
+identical to `str` except with all matching instances of `substr` replaced
+by `newSubstr`. `substr` is treated as a verbatim string to match, not a
+regular expression.
+See [`String.replaceAll`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll) on MDN.
+
+## Examples
+
+```rescript
+String.replaceAll("old old string", "old", "new") == "new new string"
+String.replaceAll("the cat and the dog", "the", "this") == "this cat and this dog"
+```
+*/
+@send
+external replaceAll: (string, string, string) => string = "replaceAll"
+
+/**
+`replaceAllRegExp(str, regex, replacement)` returns a new `string` where
+all occurrences matching regex have been replaced by `replacement`.
+The pattern must include the global (`g`) flag or a runtime TypeError will be thrown.
+See [`String.replaceAll`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll) on MDN.
+
+## Examples
+
+```rescript
+String.replaceAllRegExp("vowels be gone", %re("/[aeiou]/g"), "x") == "vxwxls bx gxnx"
+String.replaceAllRegExp("aabbcc", %re("/b/g"), ".") == "aa..cc"
+```
+*/
+@send
+external replaceAllRegExp: (string, RegExp.t, string) => string = "replaceAll"
+
+/**
+`unsafeReplaceRegExpBy0(str, regex, f)` returns a new `string` with some or all
+matches of a pattern with no capturing parentheses replaced by the value
+returned from the given function. The function receives as its parameters the
+matched string, the offset at which the match begins, and the whole string being
+matched.
+See [`String.replace`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace) on MDN.
+
+## Examples
+
+```rescript
+let str = "beautiful vowels"
+let re = %re("/[aeiou]/g")
+let matchFn = (~match, ~offset as _, ~input as _) => String.toUpperCase(match)
+String.unsafeReplaceRegExpBy0(str, re, matchFn) == "bEAUtIfUl vOwEls"
+```
+*/
+@send
+external unsafeReplaceRegExpBy0: (
+  string,
+  RegExp.t,
+  (~match: string, ~offset: int, ~input: string) => string,
+) => string = "replace"
+
+/**
+`unsafeReplaceRegExpBy1(str, regexp, f)`. Like `unsafeReplaceRegExpBy0`, but `f`
+has `group1` parameter.
+See [`String.replace`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace) on MDN.
+
+## Examples
+
+```rescript
+let str = "Jony is 40"
+let re = %re("/(Jony is )\d+/g")
+let matchFn = (~match as _, ~group1, ~offset as _, ~input as _) => {
+  group1 ++ "41"
+}
+String.unsafeReplaceRegExpBy1(str, re, matchFn) == "Jony is 41"
+```
+*/
+@send
+external unsafeReplaceRegExpBy1: (
+  string,
+  RegExp.t,
+  (~match: string, ~group1: string, ~offset: int, ~input: string) => string,
+) => string = "replace"
+
+/**
+`unsafeReplaceRegExpBy2(str, regexp, f)`. Like `unsafeReplaceRegExpBy1`, but `f`
+has two group parameters.
+See [`String.replace`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace) on MDN.
+
+## Examples
+
+```rescript
+let str = "7 times 6"
+let re = %re("/(\d+) times (\d+)/")
+let matchFn = (~match as _, ~group1, ~group2, ~offset as _, ~input as _) => {
+  switch (Int.fromString(group1), Int.fromString(group2)) {
+  | (Some(x), Some(y)) => Int.toString(x * y)
+  | _ => "???"
+  }
+}
+String.unsafeReplaceRegExpBy2(str, re, matchFn) == "42"
+```
+*/
+@send
+external unsafeReplaceRegExpBy2: (
+  string,
+  RegExp.t,
+  (~match: string, ~group1: string, ~group2: string, ~offset: int, ~input: string) => string,
+) => string = "replace"
+
+/**
+`unsafeReplaceRegExpBy3(str, regexp, f)`. Like `unsafeReplaceRegExpBy1`, but `f`
+has three group parameters.
+See [`String.replace`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace) on MDN.
+*/
+@send
+external unsafeReplaceRegExpBy3: (
+  string,
+  RegExp.t,
+  (
+    ~match: string,
+    ~group1: string,
+    ~group2: string,
+    ~group3: string,
+    ~offset: int,
+    ~input: string,
+  ) => string,
+) => string = "replace"
+
+/**
+`search(str, regexp)` returns the starting position of the first match of
+`regexp` in the given `str`, or -1 if there is no match.
+See [`String.search`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/search) on MDN.
+
+## Examples
+
+```rescript
+String.search("testing 1 2 3", %re("/\d+/")) == 8
+String.search("no numbers", %re("/\d+/")) == -1
+```
+*/
+@send
+external search: (string, RegExp.t) => int = "search"
+
+/**
+`searchOpt(str, regexp)`. Like `search`, but return an `option<int>`.
+
+## Examples
+
+```rescript
+String.searchOpt("testing 1 2 3", %re("/\d+/")) == Some(8)
+String.searchOpt("no numbers", %re("/\d+/")) == None
+```
+*/
+let searchOpt: (string, RegExp.t) => option<int>
+
+/**
+`slice(str, ~start, ~end)` returns the substring of `str` starting at
+character `start` up to but not including `end`.
+- If either `start` or `end` is negative, then it is evaluated as
+`length(str - start)` or `length(str - end)`.
+- If `end` is greater than the length of `str`, then it is treated as
+`length(str)`.
+- If `start` is greater than `end`, slice returns the empty string.
+See [`String.slice`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/slice) on MDN.
+
+## Examples
+
+```rescript
+String.slice("abcdefg", ~start=2, ~end=5) == "cde"
+String.slice("abcdefg", ~start=2, ~end=9) == "cdefg"
+String.slice("abcdefg", ~start=-4, ~end=-2) == "de"
+String.slice("abcdefg", ~start=5, ~end=1) == ""
+```
+*/
+@send
+external slice: (string, ~start: int, ~end: int) => string = "slice"
+
+/**
+`sliceToEnd(str, ~start)` returns the substring of `str` starting at character
+`start` to the end of the string.
+- If `start` is negative, then it is evaluated as `length(str - start)`.
+- If `start` is greater than the length of `str`, then sliceToEnd returns the empty string.
+See [`String.slice`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/slice) on MDN.
+
+## Examples
+
+```rescript
+String.sliceToEnd("abcdefg", ~start=4) == "efg"
+String.sliceToEnd("abcdefg", ~start=-2) == "fg"
+String.sliceToEnd("abcdefg", ~start=7) == ""
+```
+*/
+@send
+external sliceToEnd: (string, ~start: int) => string = "slice"
+
+/**
+`split(str, delimiter)` splits the given `str` at every occurrence of
+`delimiter` and returns an array of the resulting substrings.
+See [`String.split`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split) on MDN.
+
+## Examples
+
+```rescript
+String.split("2018-01-02", "-") == ["2018", "01", "02"]
+String.split("a,b,,c", ",") == ["a", "b", "", "c"]
+String.split("good::bad as great::awful", "::") == ["good", "bad as great", "awful"]
+String.split("has-no-delimiter", ";") == ["has-no-delimiter"]
+```
+*/
+@send
+external split: (string, string) => array<string> = "split"
+
+/**
+`splitAtMost(str, delimiter, ~limit)` splits the given `str` at every
+occurrence of `delimiter` and returns an array of the first `limit` resulting
+substrings. If `limit` is negative or greater than the number of substrings,
+the array will contain all the substrings.
+
+## Examples
+
+```rescript
+String.splitAtMost("ant/bee/cat/dog/elk", "/", ~limit=3) == ["ant", "bee", "cat"]
+String.splitAtMost("ant/bee/cat/dog/elk", "/", ~limit=0) == []
+String.splitAtMost("ant/bee/cat/dog/elk", "/", ~limit=9) == ["ant", "bee", "cat", "dog", "elk"]
+```
+*/
+@send
+external splitAtMost: (string, string, ~limit: int) => array<string> = "split"
+
+/**
+`splitByRegExp(str, regexp)` splits the given `str` at every occurrence of
+`regexp` and returns an array of the resulting substrings.
+See [`String.split`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split) on MDN.
+
+## Examples
+
+```rescript
+String.splitByRegExp("Jan,Feb,Mar", %re("/,/")) == [Some("Jan"), Some("Feb"), Some("Mar")]
+```
+*/
+@send
+external splitByRegExp: (string, RegExp.t) => array<option<string>> = "split"
+
+/**
+`splitByRegExpAtMost(str, regexp, ~limit)` splits the given `str` at every
+occurrence of `regexp` and returns an array of the first `limit` resulting
+substrings. If `limit` is negative or greater than the number of substrings, the
+array will contain all the substrings.
+See [`String.split`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split) on MDN.
+
+## Examples
+
+```rescript
+String.splitByRegExpAtMost("Hello World. How are you doing?", %re("/ /"), ~limit=3) == [
+  Some("Hello"),
+  Some("World."),
+  Some("How"),
+]
+```
+*/
+@send
+external splitByRegExpAtMost: (string, RegExp.t, ~limit: int) => array<option<string>> = "split"
+
+/**
+`startsWith(str, substr)` returns `true` if the `str` starts with `substr`,
+`false` otherwise.
+See [`String.startsWith`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith) on MDN.
+
+## Examples
+
+```rescript
+String.startsWith("BuckleScript", "Buckle") == true
+String.startsWith("BuckleScript", "") == true
+String.startsWith("JavaScript", "Buckle") == false
+```
+*/
+@send
+external startsWith: (string, string) => bool = "startsWith"
+
+/**
+`startsWithFrom(str, substr, n)` returns `true` if the `str` starts
+with `substr` starting at position `n`, `false` otherwise. If `n` is negative,
+the search starts at the beginning of `str`.
+See [`String.startsWith`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith) on MDN.
+
+## Examples
+
+```rescript
+String.startsWithFrom("BuckleScript", "kle", 3) == true
+String.startsWithFrom("BuckleScript", "", 3) == true
+String.startsWithFrom("JavaScript", "Buckle", 2) == false
+```
+*/
+@send
+external startsWithFrom: (string, string, int) => bool = "startsWith"
+
+/**
+`substring(str, ~start, ~end)` returns characters `start` up to but not
+including end from `str`.
+- If `start` is less than zero, it is treated as zero.
+- If `end` is zero or negative, the empty string is returned.
+- If `start` is greater than `end`, the `start` and `end` points are swapped.
+See [`String.substring`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substring) on MDN.
+
+## Examples
+
+```rescript
+String.substring("playground", ~start=3, ~end=6) == "ygr"
+String.substring("playground", ~start=6, ~end=3) == "ygr"
+String.substring("playground", ~start=4, ~end=12) == "ground"
+```
+*/
+@send
+external substring: (string, ~start: int, ~end: int) => string = "substring"
+
+/**
+`substringToEnd(str, ~start)` returns the substring of `str` from position
+`start` to the end.
+- If `start` is less than or equal to zero, the entire string is returned.
+- If `start` is greater than or equal to the length of `str`, the empty string
+is returned.
+See [`String.substring`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substring) on MDN.
+
+## Examples
+
+```rescript
+String.substringToEnd("playground", ~start=4) == "ground"
+String.substringToEnd("playground", ~start=-3) == "playground"
+String.substringToEnd("playground", ~start=12) == ""
+```
+*/
+@send
+external substringToEnd: (string, ~start: int) => string = "substring"
+
+/**
+`toLowerCase(str)` converts `str` to lower case using the locale-insensitive
+case mappings in the Unicode Character Database. Notice that the conversion can
+give different results depending upon context, for example with the Greek
+letter sigma, which has two different lower case forms, one when it is the last
+character in a string and another when it is not.
+See [`String.toLowerCase`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toLowerCase) on MDN.
+
+## Examples
+
+```rescript
+String.toLowerCase("ABC") == "abc"
+String.toLowerCase(`ΣΠ`) == `σπ`
+String.toLowerCase(`ΠΣ`) == `πς`
+```
+*/
+@send
+external toLowerCase: string => string = "toLowerCase"
+
+/**
+`toLocaleLowerCase(str)` converts `str` to lower case using the current locale.
+See [`String.toLocaleLowerCase`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toLocaleLowerCase) on MDN.
+*/
+@send
+external toLocaleLowerCase: string => string = "toLocaleLowerCase"
+
+/**
+`toUpperCase(str)` converts `str` to upper case using the locale-insensitive
+case mappings in the Unicode Character Database. Notice that the conversion can
+expand the number of letters in the result, for example the German ß
+capitalizes to two Ses in a row.
+See [`String.toUpperCase`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toUpperCase) on MDN.
+
+## Examples
+
+```rescript
+String.toUpperCase("abc") == "ABC"
+String.toUpperCase(`Straße`) == `STRASSE`
+String.toUpperCase(`πς`) == `ΠΣ`
+```
+*/
+@send
+external toUpperCase: string => string = "toUpperCase"
+
+/**
+`toLocaleUpperCase(str)` converts `str` to upper case using the current locale.
+See [`String.toLocaleUpperCase`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toLocaleUpperCase) on MDN.
+*/
+@send
+external toLocaleUpperCase: string => string = "toLocaleUpperCase"
+
+/**
+`trim(str)` returns a string that is `str` with whitespace stripped from both
+ends. Internal whitespace is not removed.
+See [`String.trim`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trim) on MDN.
+
+## Examples
+
+```rescript
+String.trim("   abc def   ") == "abc def"
+String.trim("\n\r\t abc def \n\n\t\r ") == "abc def"
+```
+*/
 @send
 external trim: string => string = "trim"
 
-/** Return a copy of the argument, with special characters
-    represented by escape sequences, following the lexical
-    conventions of OCaml.
-    All characters outside the ASCII printable range (32..126) are
-    escaped, as well as backslash and double-quote.
+/**
+`trimStart(str)` returns a string that is `str` with whitespace stripped from
+the beginning of a string. Internal whitespace is not removed.
+See [`String.trimStart`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimStart) on MDN.
+
+## Examples
+
+```rescript
+String.trimStart("   Hello world!   ") == "Hello world!   "
+String.trimStart("   Hello   world!   ") == "Hello   world!   "
+```
+*/
+@send
+external trimStart: string => string = "trimStart"
+
+/**
+`trinEnd(str)` returns a string that is `str` with whitespace stripped from the
+end of a string. Internal whitespace is not removed.
+See [`String.trimEnd`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimEnd) on MDN.
+
+## Examples
 
-    If there is no special character in the argument that needs
-    escaping, return the original string itself, not a copy.
- */
-@deprecated("Use Core instead. This will be removed in v13")
-let escaped: string => string
-
-/** [String.index s c] returns the index of the first
-   occurrence of character [c] in string [s].
-
-   Raise [Not_found] if [c] does not occur in [s]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let index: (string, char) => int
-
-/** [String.index_opt s c] returns the index of the first
-    occurrence of character [c] in string [s], or
-    [None] if [c] does not occur in [s].
-    @since 4.05 */
-@deprecated("Use Core instead. This will be removed in v13")
-let index_opt: (string, char) => option<int>
-
-/** [String.rindex s c] returns the index of the last
-   occurrence of character [c] in string [s].
-
-   Raise [Not_found] if [c] does not occur in [s]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let rindex: (string, char) => int
-
-/** [String.rindex_opt s c] returns the index of the last occurrence
-    of character [c] in string [s], or [None] if [c] does not occur in
-    [s].
-    @since 4.05 */
-@deprecated("Use Core instead. This will be removed in v13")
-let rindex_opt: (string, char) => option<int>
-
-/** [String.index_from s i c] returns the index of the
-   first occurrence of character [c] in string [s] after position [i].
-   [String.index s c] is equivalent to [String.index_from s 0 c].
-
-   Raise [Invalid_argument] if [i] is not a valid position in [s].
-   Raise [Not_found] if [c] does not occur in [s] after position [i]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let index_from: (string, int, char) => int
-
-/** [String.index_from_opt s i c] returns the index of the
-    first occurrence of character [c] in string [s] after position [i]
-    or [None] if [c] does not occur in [s] after position [i].
-
-    [String.index_opt s c] is equivalent to [String.index_from_opt s 0 c].
-    Raise [Invalid_argument] if [i] is not a valid position in [s].
-
-    @since 4.05
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let index_from_opt: (string, int, char) => option<int>
-
-/** [String.rindex_from s i c] returns the index of the
-   last occurrence of character [c] in string [s] before position [i+1].
-   [String.rindex s c] is equivalent to
-   [String.rindex_from s (String.length s - 1) c].
-
-   Raise [Invalid_argument] if [i+1] is not a valid position in [s].
-   Raise [Not_found] if [c] does not occur in [s] before position [i+1]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let rindex_from: (string, int, char) => int
-
-/** [String.rindex_from_opt s i c] returns the index of the
-   last occurrence of character [c] in string [s] before position [i+1]
-   or [None] if [c] does not occur in [s] before position [i+1].
-
-   [String.rindex_opt s c] is equivalent to
-   [String.rindex_from_opt s (String.length s - 1) c].
-
-   Raise [Invalid_argument] if [i+1] is not a valid position in [s].
-
-    @since 4.05
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let rindex_from_opt: (string, int, char) => option<int>
-
-/** [String.contains s c] tests if character [c]
-   appears in the string [s]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let contains: (string, char) => bool
-
-/** [String.contains_from s start c] tests if character [c]
-   appears in [s] after position [start].
-   [String.contains s c] is equivalent to
-   [String.contains_from s 0 c].
-
-   Raise [Invalid_argument] if [start] is not a valid position in [s]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let contains_from: (string, int, char) => bool
-
-/** [String.rcontains_from s stop c] tests if character [c]
-   appears in [s] before position [stop+1].
-
-   Raise [Invalid_argument] if [stop < 0] or [stop+1] is not a valid
-   position in [s]. */
-@deprecated("Use Core instead. This will be removed in v13")
-let rcontains_from: (string, int, char) => bool
-
-/** Return a copy of the argument, with all lowercase letters
-   translated to uppercase, using the US-ASCII character set.
-   @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let uppercase_ascii: string => string
-
-/** Return a copy of the argument, with all uppercase letters
-   translated to lowercase, using the US-ASCII character set.
-   @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let lowercase_ascii: string => string
-
-/** Return a copy of the argument, with the first character set to uppercase,
-   using the US-ASCII character set.
-   @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let capitalize_ascii: string => string
-
-/** Return a copy of the argument, with the first character set to lowercase,
-   using the US-ASCII character set.
-   @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-let uncapitalize_ascii: string => string
-
-/** An alias for the type of strings. */
-@deprecated("Use `string` instead. This will be removed in v13")
-type t = string
-
-/** The comparison function for strings, with the same specification as
-    {!Pervasives.compare}.  Along with the type [t], this function [compare]
-    allows the module [String] to be passed as argument to the functors
-    {!Set.Make} and {!Map.Make}. */
-@deprecated("Use Core instead. This will be removed in v13")
-external compare: (t, t) => int = "%compare"
-
-/** The equal function for strings.
-    @since 4.03.0 */
-@deprecated("Use Core instead. This will be removed in v13")
-external equal: (t, t) => bool = "%equal"
-
-/** [String.split_on_char sep s] returns the list of all (possibly empty)
-    substrings of [s] that are delimited by the [sep] character.
-
-    The function's output is specified by the following invariants:
+```rescript
+String.trimEnd("   Hello world!   ") == "   Hello world!"
+String.trimEnd("   Hello   world!   ") == "   Hello   world!"
+```
+*/
+@send
+external trimEnd: string => string = "trimEnd"
+
+/**
+`padStart(str, n, padStr)` returns a string that has been padded with `padStr`
+(multiple times, if needed) until the resulting string reaches the given `n`
+length. The padding is applied from the start of the current string.
+See [`String.padStart`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart) on MDN.
+
+## Examples
+
+```rescript
+String.padStart("abc", 5, " ") == "  abc"
+String.padStart("abc", 6, "123465") == "123abc"
+```
+*/
+@send
+external padStart: (string, int, string) => string = "padStart"
+
+/**
+`padEnd(str, n, padStr)` returns a string that has been padded with `padStr`
+(multiple times, if needed) until the resulting string reaches the given `n`
+length. The padding is applied from the end of the current string.
+See [`String.padEnd`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padEnd) on MDN.
+
+## Examples
 
-    - The list is not empty.
-    - Concatenating its elements using [sep] as a separator returns a
-      string equal to the input ([String.concat (String.make 1 sep)
-      (String.split_on_char sep s) = s]).
-    - No string in the result contains the [sep] character.
-
-    @since 4.04.0
-*/
-@deprecated("Use Core instead. This will be removed in v13")
-let split_on_char: (char, string) => list<string>
-
-/* The following is for system use only. Do not call directly. */
-@deprecated("Use Core instead. This will be removed in v13") @send
-external unsafe_get: (string, int) => char = "codePointAt"
+```rescript
+String.padEnd("Hello", 10, ".") == "Hello....."
+String.padEnd("abc", 1, "") == "abc"
+```
+*/
+@send
+external padEnd: (string, int, string) => string = "padEnd"
+
+// TODO: add docs
+@get_index external getSymbol: (string, Symbol.t) => option<'a> = ""
+@get_index external getSymbolUnsafe: (string, Symbol.t) => 'a = ""
+@set_index external setSymbol: (string, Symbol.t, 'a) => unit = ""
+
+/**
+`localeCompare(referenceStr, compareStr)` returns a float than indicatings
+whether a reference string comes before or after, or is the same as the given
+string in sort order. If `referenceStr` occurs before `compareStr` positive if
+the `referenceStr` occurs after `compareStr`, `0` if they are equivalent.
+Do not rely on exact return values of `-1` or `1`
+See [`String.localeCompare`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/localeCompare) on MDN.
+
+## Examples
+
+```rescript
+String.localeCompare("a", "c") < 0.0 == true
+String.localeCompare("a", "a") == 0.0
+```
+*/
+@send
+external localeCompare: (string, string) => float = "localeCompare"
diff --git a/runtime/Symbol.res b/runtime/Symbol.res
new file mode 100644
index 0000000000..8b4c1b218d
--- /dev/null
+++ b/runtime/Symbol.res
@@ -0,0 +1,19 @@
+type t = Js.Types.symbol
+
+@val external make: string => t = "Symbol"
+@val external getFor: string => t = "Symbol.for"
+@val external keyFor: t => option<string> = "Symbol.keyFor"
+
+@val external asyncIterator: t = "Symbol.asyncIterator"
+@val external hasInstance: t = "Symbol.hasInstance"
+@val external isConcatSpreadable: t = "Symbol.isConcatSpreadable"
+@val external iterator: t = "Symbol.iterator"
+@val external match: t = "Symbol.match"
+@val external matchAll: t = "Symbol.matchAll"
+@val external replace: t = "Symbol.replace"
+@val external search: t = "Symbol.search"
+@val external species: t = "Symbol.species"
+@val external split: t = "Symbol.split"
+@val external toPrimitive: t = "Symbol.toPrimitive"
+@val external toStringTag: t = "Symbol.toStringTag"
+@val external unscopables: t = "Symbol.unscopables"
diff --git a/runtime/Type.res b/runtime/Type.res
new file mode 100644
index 0000000000..d29bb28c78
--- /dev/null
+++ b/runtime/Type.res
@@ -0,0 +1,45 @@
+type t = [#undefined | #object | #boolean | #number | #bigint | #string | #symbol | #function]
+
+external typeof: 'a => t = "#typeof"
+
+module Classify = {
+  type function = Js.Types.function_val
+  type object = Js.Types.obj_val
+
+  type t =
+    | Bool(bool)
+    | Null
+    | Undefined
+    | String(string)
+    | Number(float)
+    | Object(object)
+    | Function(function)
+    | Symbol(Symbol.t)
+    | BigInt(bigint)
+
+  @val external _internalClass: 'a => string = "Object.prototype.toString.call"
+  external _asBool: 'a => bool = "%identity"
+  external _asString: 'a => string = "%identity"
+  external _asFloat: 'a => float = "%identity"
+  external _asObject: 'a => object = "%identity"
+  external _asFunction: 'a => function = "%identity"
+  external _asSymbol: 'a => Symbol.t = "%identity"
+  external _asBigInt: 'a => bigint = "%identity"
+
+  let classify = value => {
+    switch _internalClass(value) {
+    | "[object Boolean]" => Bool(_asBool(value))
+    | "[object Null]" => Null
+    | "[object Undefined]" => Undefined
+    | "[object String]" => String(_asString(value))
+    | "[object Number]" => Number(_asFloat(value))
+    | "[object Function]"
+    | "[object GeneratorFunction]"
+    | "[object AsyncFunction]" =>
+      Function(_asFunction(value))
+    | "[object Symbol]" => Symbol(_asSymbol(value))
+    | "[object BigInt]" => BigInt(_asBigInt(value))
+    | _ => Object(_asObject(value))
+    }
+  }
+}
diff --git a/runtime/Type.resi b/runtime/Type.resi
new file mode 100644
index 0000000000..ee6519b653
--- /dev/null
+++ b/runtime/Type.resi
@@ -0,0 +1,77 @@
+/***
+Utilities for classifying the type of JavaScript values at runtime.
+*/
+
+/**
+The possible types of JavaScript values.
+*/
+type t = [#undefined | #object | #boolean | #number | #bigint | #string | #symbol | #function]
+
+/**
+`typeof(someValue)`
+
+Returns the underlying JavaScript type of any runtime value.
+
+See [`typeof`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/typeof) on MDN.
+
+## Examples
+```rescript
+Console.log(Type.typeof("Hello")) // Logs "string" to the console.
+
+let someVariable = true
+
+switch someVariable->Type.typeof {
+| #boolean => Console.log("This is a bool, yay!")
+| _ => Console.log("Oh, not a bool sadly...")
+}
+```
+*/
+external typeof: 'a => t = "#typeof"
+
+module Classify: {
+  /***
+  Classifies JavaScript runtime values.
+  */
+
+  /**
+  An abstract type representing a JavaScript function.
+
+  See [`function`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function) on MDN.
+  */
+  type function
+
+  /**
+  An abstract type representing a JavaScript object.
+
+  See [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) on MDN.
+  */
+  type object
+
+  /**
+  The type representing a classified JavaScript value.
+  */
+  type t =
+    | Bool(bool)
+    | Null
+    | Undefined
+    | String(string)
+    | Number(float)
+    | Object(object)
+    | Function(function)
+    | Symbol(Symbol.t)
+    | BigInt(bigint)
+
+  /**
+`classify(anyValue)`
+Classifies a JavaScript value.
+
+## Examples
+```rescript
+switch %raw(`null`)->Type.Classify.classify {
+| Null => Console.log("Yup, that's null.")
+| _ => Console.log("This doesn't actually appear to be null...")
+}
+```
+*/
+  let classify: 'a => t
+}
diff --git a/runtime/TypedArray.res b/runtime/TypedArray.res
new file mode 100644
index 0000000000..35ccbc4fa3
--- /dev/null
+++ b/runtime/TypedArray.res
@@ -0,0 +1,77 @@
+type t<'a>
+
+@get_index external get: (t<'a>, int) => option<'a> = ""
+@set_index external set: (t<'a>, int, 'a) => unit = ""
+
+@get external buffer: t<'a> => ArrayBuffer.t = "buffer"
+@get external byteLength: t<'a> => int = "byteLength"
+@get external byteOffset: t<'a> => int = "byteOffset"
+
+@send external setArray: (t<'a>, array<'a>) => unit = "set"
+@send external setArrayFrom: (t<'a>, array<'a>, int) => unit = "set"
+
+@get external length: t<'a> => int = "length"
+
+@send external copyAllWithin: (t<'a>, ~target: int) => array<'a> = "copyWithin"
+@send external copyWithinToEnd: (t<'a>, ~target: int, ~start: int) => array<'a> = "copyWithin"
+@send
+external copyWithin: (t<'a>, ~target: int, ~start: int, ~end: int) => array<'a> = "copyWithin"
+
+@send external fillAll: (t<'a>, 'a) => t<'a> = "fill"
+@send external fillToEnd: (t<'a>, 'a, ~start: int) => t<'a> = "fill"
+@send external fill: (t<'a>, 'a, ~start: int, ~end: int) => t<'a> = "fill"
+
+@send external reverse: t<'a> => unit = "reverse"
+@send external toReversed: t<'a> => t<'a> = "toReversed"
+
+@send external sort: (t<'a>, ('a, 'a) => Ordering.t) => unit = "sort"
+@send external toSorted: (t<'a>, ('a, 'a) => Ordering.t) => t<'a> = "toSorted"
+
+@send external with: (t<'a>, int, 'a) => t<'a> = "with"
+
+@send external includes: (t<'a>, 'a) => bool = "includes"
+
+@send external indexOf: (t<'a>, 'a) => int = "indexOf"
+@send external indexOfFrom: (t<'a>, 'a, int) => int = "indexOf"
+
+@send external joinWith: (t<'a>, string) => string = "join"
+
+@send external lastIndexOf: (t<'a>, 'a) => int = "lastIndexOf"
+@send external lastIndexOfFrom: (t<'a>, 'a, int) => int = "lastIndexOf"
+
+@send external slice: (t<'a>, ~start: int, ~end: int) => t<'a> = "slice"
+@send external sliceToEnd: (t<'a>, ~start: int) => t<'a> = "slice"
+@send external copy: t<'a> => t<'a> = "slice"
+
+@send external subarray: (t<'a>, ~start: int, ~end: int) => t<'a> = "subarray"
+@send external subarrayToEnd: (t<'a>, ~start: int) => t<'a> = "subarray"
+
+@send external toString: t<'a> => string = "toString"
+@send external toLocaleString: t<'a> => string = "toLocaleString"
+
+@send external every: (t<'a>, 'a => bool) => bool = "every"
+@send external everyWithIndex: (t<'a>, ('a, int) => bool) => bool = "every"
+
+@send external filter: (t<'a>, 'a => bool) => t<'a> = "filter"
+@send external filterWithIndex: (t<'a>, ('a, int) => bool) => t<'a> = "filter"
+
+@send external find: (t<'a>, 'a => bool) => option<'a> = "find"
+@send external findWithIndex: (t<'a>, ('a, int) => bool) => option<'a> = "find"
+
+@send external findIndex: (t<'a>, 'a => bool) => int = "findIndex"
+@send external findIndexWithIndex: (t<'a>, ('a, int) => bool) => int = "findIndex"
+
+@send external forEach: (t<'a>, 'a => unit) => unit = "forEach"
+@send external forEachWithIndex: (t<'a>, ('a, int) => unit) => unit = "forEach"
+
+@send external map: (t<'a>, 'a => 'b) => t<'b> = "map"
+@send external mapWithIndex: (t<'a>, ('a, int) => 'b) => t<'b> = "map"
+
+@send external reduce: (t<'a>, ('b, 'a) => 'b, 'b) => 'b = "reduce"
+@send external reduceWithIndex: (t<'a>, ('b, 'a, int) => 'b, 'b) => 'b = "reduce"
+
+@send external reduceRight: (t<'a>, ('b, 'a) => 'b, 'b) => 'b = "reduceRight"
+@send external reduceRightWithIndex: (t<'a>, ('b, 'a, int) => 'b, 'b) => 'b = "reduceRight"
+
+@send external some: (t<'a>, 'a => bool) => bool = "some"
+@send external someWithIndex: (t<'a>, ('a, int) => bool) => bool = "some"
diff --git a/runtime/Uint16Array.res b/runtime/Uint16Array.res
new file mode 100644
index 0000000000..115caf8a2f
--- /dev/null
+++ b/runtime/Uint16Array.res
@@ -0,0 +1,53 @@
+/** The `Uint16Array` typed array represents an array of 16-bit unsigned integers in platform byte order. See [Uint16Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array)
+*/
+type t = TypedArray.t<int>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "Uint16Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `Uint16Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array/Uint16Array)
+*/
+@new
+external fromArray: array<int> => t = "Uint16Array"
+
+/** `fromBuffer` creates a `Uint16Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array/Uint16Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "Uint16Array"
+
+/** `fromBufferToEnd` creates a `Uint16Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array/Uint16Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "Uint16Array"
+
+/** `fromBufferWithRange` creates a `Uint16Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array/Uint16Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "Uint16Array"
+
+/** `fromLength` creates a zero-initialized `Uint16Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array/Uint16Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "Uint16Array"
+
+/** `fromArrayLikeOrIterable` creates a `Uint16Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "Uint16Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `Uint16Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => int) => t = "Uint16Array.from"
diff --git a/runtime/Uint32Array.res b/runtime/Uint32Array.res
new file mode 100644
index 0000000000..ba6693054a
--- /dev/null
+++ b/runtime/Uint32Array.res
@@ -0,0 +1,53 @@
+/** The `Uint32Array` typed array represents an array of 32-bit unsigned integers in platform byte order. See [Uint32Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array)
+*/
+type t = TypedArray.t<int>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "Uint32Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `Uint32Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array/Uint32Array)
+*/
+@new
+external fromArray: array<int> => t = "Uint32Array"
+
+/** `fromBuffer` creates a `Uint32Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array/Uint32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "Uint32Array"
+
+/** `fromBufferToEnd` creates a `Uint32Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array/Uint32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "Uint32Array"
+
+/** `fromBufferWithRange` creates a `Uint32Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array/Uint32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "Uint32Array"
+
+/** `fromLength` creates a zero-initialized `Uint32Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array/Uint32Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "Uint32Array"
+
+/** `fromArrayLikeOrIterable` creates a `Uint32Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "Uint32Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `Uint32Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => int) => t = "Uint32Array.from"
diff --git a/runtime/Uint8Array.res b/runtime/Uint8Array.res
new file mode 100644
index 0000000000..2233a039b3
--- /dev/null
+++ b/runtime/Uint8Array.res
@@ -0,0 +1,53 @@
+/** The `Uint8Array` typed array represents an array of 8-bit unsigned integers. See [Uint8Array on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array)
+*/
+type t = TypedArray.t<int>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "Uint8Array.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `Uint8Array` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/Uint8Array)
+*/
+@new
+external fromArray: array<int> => t = "Uint8Array"
+
+/** `fromBuffer` creates a `Uint8Array` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/Uint8Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "Uint8Array"
+
+/** `fromBufferToEnd` creates a `Uint8Array` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/Uint8Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "Uint8Array"
+
+/** `fromBufferWithRange` creates a `Uint8Array` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/Uint8Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t = "Uint8Array"
+
+/** `fromLength` creates a zero-initialized `Uint8Array` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/Uint8Array)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "Uint8Array"
+
+/** `fromArrayLikeOrIterable` creates a `Uint8Array` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "Uint8Array.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `Uint8Array` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => int) => t = "Uint8Array.from"
diff --git a/runtime/Uint8ClampedArray.res b/runtime/Uint8ClampedArray.res
new file mode 100644
index 0000000000..633dd4ca18
--- /dev/null
+++ b/runtime/Uint8ClampedArray.res
@@ -0,0 +1,54 @@
+/** The `Uint8ClampedArray` typed array represents an array of 8-bit unsigned integers clamped to 0-255. See [Uint8ClampedArray on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray)
+*/
+type t = TypedArray.t<int>
+
+module Constants = {
+  /**`bytesPerElement` returns the element size. See [BYTES_PER_ELEMENT on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/BYTES_PER_ELEMENT)
+  */
+  @val
+  external bytesPerElement: int = "Uint8ClampedArray.BYTES_PER_ELEMENT"
+}
+
+/** `fromArray` creates a `Uint8ClampedArray` from an array of values. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray/Uint8ClampedArray)
+*/
+@new
+external fromArray: array<int> => t = "Uint8ClampedArray"
+
+/** `fromBuffer` creates a `Uint8ClampedArray` from an `ArrayBuffer.t`. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray/Uint8ClampedArray)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBuffer: ArrayBuffer.t => t = "Uint8ClampedArray"
+
+/** `fromBufferToEnd` creates a `Uint8ClampedArray` from an `ArrayBuffer.t`, starting at a particular offset and continuing through to the end. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray/Uint8ClampedArray)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferToEnd: (ArrayBuffer.t, ~byteOffset: int) => t = "Uint8ClampedArray"
+
+/** `fromBufferWithRange` creates a `Uint8ClampedArray` from an `ArrayBuffer.t`, starting at a particular offset and consuming `length` **bytes**. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray/Uint8ClampedArray)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromBufferWithRange: (ArrayBuffer.t, ~byteOffset: int, ~length: int) => t =
+  "Uint8ClampedArray"
+
+/** `fromLength` creates a zero-initialized `Uint8ClampedArray` to hold the specified count of numbers; this is **not** a byte length. See [TypedArray constructor on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray/Uint8ClampedArray)
+
+**Note:** This is a potentially unsafe operation. Ensure the buffer is large enough and only accessed within its bounds. 
+*/
+@new
+external fromLength: int => t = "Uint8ClampedArray"
+
+/** `fromArrayLikeOrIterable` creates a `Uint8ClampedArray` from an array-like or iterable object. See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterable: 'a => t = "Uint8ClampedArray.from"
+
+/** `fromArrayLikeOrIterableWithMap` creates a `Uint8ClampedArray` from an array-like or iterable object and applies the mapping function to each item. The mapping function expects (value, index). See [TypedArray.from on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from)
+*/
+@val
+external fromArrayLikeOrIterableWithMap: ('a, ('b, int) => int) => t = "Uint8ClampedArray.from"
diff --git a/runtime/WeakMap.res b/runtime/WeakMap.res
new file mode 100644
index 0000000000..4bc91810da
--- /dev/null
+++ b/runtime/WeakMap.res
@@ -0,0 +1,8 @@
+type t<'k, 'v> = Js.WeakMap.t<'k, 'v>
+
+@new external make: unit => t<'k, 'v> = "WeakMap"
+
+@send external get: (t<'k, 'v>, 'k) => option<'v> = "get"
+@send external has: (t<'k, 'v>, 'k) => bool = "has"
+@send external set: (t<'k, 'v>, 'k, 'v) => t<'k, 'v> = "set"
+@send external delete: (t<'k, 'v>, 'k) => bool = "delete"
diff --git a/runtime/WeakSet.res b/runtime/WeakSet.res
new file mode 100644
index 0000000000..851329c80d
--- /dev/null
+++ b/runtime/WeakSet.res
@@ -0,0 +1,7 @@
+type t<'a> = Js.WeakSet.t<'a>
+
+@new external make: unit => t<'a> = "WeakSet"
+
+@send external add: (t<'a>, 'a) => t<'a> = "add"
+@send external delete: (t<'a>, 'a) => bool = "delete"
+@send external has: (t<'a>, 'a) => bool = "has"
diff --git a/runtime/rescript.json b/runtime/rescript.json
index 2ec055d9db..abb683bc73 100644
--- a/runtime/rescript.json
+++ b/runtime/rescript.json
@@ -9,7 +9,7 @@
     "-make-runtime",
     "-nostdlib",
     "-nopervasives",
-    "-open Pervasives",
+    "-open Pervasives_mini",
     "-no-keep-locs",
     "-no-alias-deps",
     "-bs-no-version-header",
diff --git a/scripts/buildRuntime.sh b/scripts/buildRuntime.sh
index 17ab6f13dc..8cf8ad5e92 100755
--- a/scripts/buildRuntime.sh
+++ b/scripts/buildRuntime.sh
@@ -2,14 +2,16 @@
 set -e
 shopt -s extglob
 
+(cd runtime && ../cli/rescript clean)
+
 rm -f lib/es6/*.js lib/js/*.js lib/ocaml/*
 mkdir -p lib/es6 lib/js lib/ocaml
 mkdir -p runtime/lib/es6 runtime/lib/js
 
 (cd runtime && ../cli/rescript build)
 
-cp runtime/lib/es6/*.js lib/es6
-cp runtime/lib/js/*.js lib/js
-cp runtime/lib/bs/!(belt_internal*).cmi lib/ocaml/
-cp runtime/lib/bs/*.@(cmj|cmt|cmti) lib/ocaml/
-cp runtime/*.@(res|resi) lib/ocaml/
+cp runtime/lib/es6/!(Pervasives_mini).js lib/es6
+cp runtime/lib/js/!(Pervasives_mini).js lib/js
+cp runtime/lib/bs/!(Pervasives_mini|Belt_internal*).cmi lib/ocaml/
+cp runtime/lib/bs/!(Pervasives_mini).@(cmi|cmj|cmt|cmti) lib/ocaml/
+cp runtime/!(Pervasives_mini).@(res|resi) lib/ocaml/
diff --git a/tests/tests/src/UntaggedVariants.js b/tests/tests/src/UntaggedVariants.js
index f464f089b0..c819b5b3c7 100644
--- a/tests/tests/src/UntaggedVariants.js
+++ b/tests/tests/src/UntaggedVariants.js
@@ -600,6 +600,8 @@ let MergeCases = {
   can_merge: can_merge
 };
 
+let $$Array;
+
 let i = 42;
 
 let i2 = 42.5;
@@ -613,6 +615,7 @@ let w = {
   y: ""
 };
 
+exports.$$Array = $$Array;
 exports.i = i;
 exports.i2 = i2;
 exports.s = s;
diff --git a/tests/tests/src/UntaggedVariants.res b/tests/tests/src/UntaggedVariants.res
index 3972053a72..2644c010d6 100644
--- a/tests/tests/src/UntaggedVariants.res
+++ b/tests/tests/src/UntaggedVariants.res
@@ -1,3 +1,5 @@
+module Array = Ocaml_Array
+
 @unboxed
 type t = A | I(int) | S(string)
 @unboxed
diff --git a/tests/tests/src/alias_test.res b/tests/tests/src/alias_test.res
index d72b52c547..40b333461e 100644
--- a/tests/tests/src/alias_test.res
+++ b/tests/tests/src/alias_test.res
@@ -1,3 +1,5 @@
+module String = Ocaml_String
+
 let a0 = "hello "
 
 let a1 = a0
diff --git a/tests/tests/src/array_safe_get.js b/tests/tests/src/array_safe_get.js
index 0ba0e474b1..1f08bf078c 100644
--- a/tests/tests/src/array_safe_get.js
+++ b/tests/tests/src/array_safe_get.js
@@ -23,6 +23,9 @@ try {
   }
 }
 
+let $$Array;
+
+exports.$$Array = $$Array;
 exports.x = x;
 exports.y = y;
 /* y Not a pure module */
diff --git a/tests/tests/src/array_safe_get.res b/tests/tests/src/array_safe_get.res
index 436efebb50..50113f5b9d 100644
--- a/tests/tests/src/array_safe_get.res
+++ b/tests/tests/src/array_safe_get.res
@@ -1,3 +1,5 @@
+module Array = Ocaml_Array
+
 let x = [1, 2]
 let y = try x[3] catch {
 | Invalid_argument(msg) =>
diff --git a/tests/tests/src/array_subtle_test.js b/tests/tests/src/array_subtle_test.js
index 2046a8ac88..c8d11befb2 100644
--- a/tests/tests/src/array_subtle_test.js
+++ b/tests/tests/src/array_subtle_test.js
@@ -36,34 +36,34 @@ let v = [
   3
 ];
 
-eq("File \"array_subtle_test.res\", line 14, characters 12-19", [
+eq("File \"array_subtle_test.res\", line 16, characters 12-19", [
   4,
   v.length
 ]);
 
-eq("File \"array_subtle_test.res\", line 17, characters 5-12", [
+eq("File \"array_subtle_test.res\", line 19, characters 5-12", [
   5,
   v.push(3)
 ]);
 
-eq("File \"array_subtle_test.res\", line 18, characters 5-12", [
+eq("File \"array_subtle_test.res\", line 20, characters 5-12", [
   5,
   v.length
 ]);
 
-eq("File \"array_subtle_test.res\", line 19, characters 5-12", [
+eq("File \"array_subtle_test.res\", line 21, characters 5-12", [
   5,
   v.length
 ]);
 
-eq("File \"array_subtle_test.res\", line 23, characters 5-12", [
+eq("File \"array_subtle_test.res\", line 25, characters 5-12", [
   3,
   Primitive_array.get(v, 2)
 ]);
 
 Primitive_array.set(v, 2, 4);
 
-eq("File \"array_subtle_test.res\", line 25, characters 5-12", [
+eq("File \"array_subtle_test.res\", line 27, characters 5-12", [
   4,
   Primitive_array.get(v, 2)
 ]);
@@ -72,7 +72,7 @@ while (v.length > 0) {
   v.pop();
 };
 
-eq("File \"array_subtle_test.res\", line 32, characters 5-12", [
+eq("File \"array_subtle_test.res\", line 34, characters 5-12", [
   0,
   v.length
 ]);
@@ -111,23 +111,26 @@ function fff4(x) {
   }
 }
 
-eq("File \"array_subtle_test.res\", line 64, characters 3-10", [
+eq("File \"array_subtle_test.res\", line 66, characters 3-10", [
   fff3([]),
   1
 ]);
 
-eq("File \"array_subtle_test.res\", line 65, characters 3-10", [
+eq("File \"array_subtle_test.res\", line 67, characters 3-10", [
   fff4([]),
   2
 ]);
 
-eq("File \"array_subtle_test.res\", line 66, characters 3-10", [
+eq("File \"array_subtle_test.res\", line 68, characters 3-10", [
   fff4([1]),
   1
 ]);
 
 Mt.from_pair_suites("Array_subtle_test", suites.contents);
 
+let $$Array;
+
+exports.$$Array = $$Array;
 exports.suites = suites;
 exports.test_id = test_id;
 exports.eq = eq;
diff --git a/tests/tests/src/array_subtle_test.res b/tests/tests/src/array_subtle_test.res
index a24b8a460e..eccff87e3f 100644
--- a/tests/tests/src/array_subtle_test.res
+++ b/tests/tests/src/array_subtle_test.res
@@ -1,3 +1,5 @@
+module Array = Ocaml_Array
+
 let suites: ref<Mt.pair_suites> = ref(list{})
 let test_id = ref(0)
 let eq = (loc, (x, y)) => {
diff --git a/tests/tests/src/async_await.js b/tests/tests/src/async_await.js
index 6bc2c04245..670f6a7869 100644
--- a/tests/tests/src/async_await.js
+++ b/tests/tests/src/async_await.js
@@ -1,7 +1,6 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 'use strict';
 
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 function next(n) {
   return n + 1 | 0;
@@ -30,7 +29,7 @@ let arr = [
 
 let toplevelAwait = await topFoo();
 
-let toplevelAwait2 = Primitive_array.get(arr, await topFoo());
+let toplevelAwait2 = arr[await topFoo()];
 
 async function f(value) {
   return await Promise.resolve(1);
diff --git a/tests/tests/src/bdd.js b/tests/tests/src/bdd.js
index b09df2a166..60d94b46e7 100644
--- a/tests/tests/src/bdd.js
+++ b/tests/tests/src/bdd.js
@@ -72,7 +72,7 @@ function resize(newSize) {
             RE_EXN_ID: "Assert_failure",
             _1: [
               "bdd.res",
-              60,
+              62,
               13
             ],
             Error: new Error()
@@ -82,7 +82,7 @@ function resize(newSize) {
           RE_EXN_ID: "Assert_failure",
           _1: [
             "bdd.res",
-            60,
+            62,
             13
           ],
           Error: new Error()
@@ -148,7 +148,7 @@ function mkNode(low, v, high) {
             RE_EXN_ID: "Assert_failure",
             _1: [
               "bdd.res",
-              121,
+              123,
               15
             ],
             Error: new Error()
@@ -158,7 +158,7 @@ function mkNode(low, v, high) {
           RE_EXN_ID: "Assert_failure",
           _1: [
             "bdd.res",
-            121,
+            123,
             15
           ],
           Error: new Error()
@@ -403,7 +403,7 @@ function main() {
     RE_EXN_ID: "Assert_failure",
     _1: [
       "bdd.res",
-      302,
+      304,
       2
     ],
     Error: new Error()
@@ -412,6 +412,8 @@ function main() {
 
 main();
 
+let $$Array;
+
 let initSize_1 = 8191;
 
 let zero = "Zero";
@@ -420,6 +422,7 @@ let one = "One";
 
 let cacheSize = 1999;
 
+exports.$$Array = $$Array;
 exports.$$eval = $$eval;
 exports.getId = getId;
 exports.initSize_1 = initSize_1;
diff --git a/tests/tests/src/bdd.res b/tests/tests/src/bdd.res
index 3b22084a5e..e956cf2050 100644
--- a/tests/tests/src/bdd.res
+++ b/tests/tests/src/bdd.res
@@ -15,6 +15,8 @@
 /* Translated to Caml by Xavier Leroy */
 /* Original code written in SML by ... */
 
+module Array = Ocaml_Array
+
 type rec bdd = One | Zero | Node(bdd, int, int, bdd)
 
 let rec eval = (bdd, vars) =>
diff --git a/tests/tests/src/belt_hashmap_test.js b/tests/tests/src/belt_hashmap_test.js
index 1352ab03ec..7feb63329e 100644
--- a/tests/tests/src/belt_hashmap_test.js
+++ b/tests/tests/src/belt_hashmap_test.js
@@ -3,10 +3,10 @@
 
 let Mocha = require("mocha");
 let Belt_Id = require("rescript/lib/js/Belt_Id.js");
-let Hashtbl = require("rescript/lib/js/Hashtbl.js");
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
 let Test_utils = require("./test_utils.js");
 let Belt_HashMap = require("rescript/lib/js/Belt_HashMap.js");
+let Ocaml_Hashtbl = require("./ocaml_compat/Ocaml_Hashtbl.js");
 let Primitive_int = require("rescript/lib/js/Primitive_int.js");
 let Belt_SortArray = require("rescript/lib/js/Belt_SortArray.js");
 let Array_data_util = require("./array_data_util.js");
@@ -15,7 +15,7 @@ function intEq(x, y) {
   return x === y;
 }
 
-let intHash = Hashtbl.hash;
+let intHash = Ocaml_Hashtbl.hash;
 
 let cmp = Primitive_int.compare;
 
@@ -28,8 +28,8 @@ Mocha.describe("Belt_hashmap_test", () => {
     let u = Belt_Array.concat(Array_data_util.randomRange(30, 100), Array_data_util.randomRange(40, 120));
     let v = Belt_Array.zip(u, u);
     let xx = Belt_HashMap.fromArray(v, Y);
-    Test_utils.eq("File \"belt_hashmap_test.res\", line 21, characters 7-14", Belt_HashMap.size(xx), 91);
-    Test_utils.eq("File \"belt_hashmap_test.res\", line 22, characters 7-14", Belt_SortArray.stableSortBy(Belt_HashMap.keysToArray(xx), cmp), Array_data_util.range(30, 120));
+    Test_utils.eq("File \"belt_hashmap_test.res\", line 22, characters 7-14", Belt_HashMap.size(xx), 91);
+    Test_utils.eq("File \"belt_hashmap_test.res\", line 23, characters 7-14", Belt_SortArray.stableSortBy(Belt_HashMap.keysToArray(xx), cmp), Array_data_util.range(30, 120));
   });
   Mocha.test("mergeMany", () => {
     Belt_HashMap.mergeMany(empty, [
@@ -50,26 +50,28 @@ Mocha.describe("Belt_hashmap_test", () => {
         2
       ]
     ]);
-    Test_utils.eq("File \"belt_hashmap_test.res\", line 27, characters 7-14", Belt_HashMap.get(empty, 2), 2);
-    Test_utils.eq("File \"belt_hashmap_test.res\", line 28, characters 7-14", Belt_HashMap.size(empty), 3);
+    Test_utils.eq("File \"belt_hashmap_test.res\", line 28, characters 7-14", Belt_HashMap.get(empty, 2), 2);
+    Test_utils.eq("File \"belt_hashmap_test.res\", line 29, characters 7-14", Belt_HashMap.size(empty), 3);
   });
   Mocha.test("remove", () => {
     let u = Belt_Array.concat(Array_data_util.randomRange(0, 100000), Array_data_util.randomRange(0, 100));
     let v = Belt_HashMap.make(40, Y);
     Belt_HashMap.mergeMany(v, Belt_Array.zip(u, u));
-    Test_utils.eq("File \"belt_hashmap_test.res\", line 35, characters 7-14", Belt_HashMap.size(v), 100001);
+    Test_utils.eq("File \"belt_hashmap_test.res\", line 36, characters 7-14", Belt_HashMap.size(v), 100001);
     for (let i = 0; i <= 1000; ++i) {
       Belt_HashMap.remove(v, i);
     }
-    Test_utils.eq("File \"belt_hashmap_test.res\", line 39, characters 7-14", Belt_HashMap.size(v), 99000);
+    Test_utils.eq("File \"belt_hashmap_test.res\", line 40, characters 7-14", Belt_HashMap.size(v), 99000);
     for (let i$1 = 0; i$1 <= 2000; ++i$1) {
       Belt_HashMap.remove(v, i$1);
     }
-    Test_utils.eq("File \"belt_hashmap_test.res\", line 43, characters 7-14", Belt_HashMap.size(v), 98000);
-    Test_utils.ok("File \"belt_hashmap_test.res\", line 44, characters 7-14", Belt_Array.every(Array_data_util.range(2001, 100000), x => Belt_HashMap.has(v, x)));
+    Test_utils.eq("File \"belt_hashmap_test.res\", line 44, characters 7-14", Belt_HashMap.size(v), 98000);
+    Test_utils.ok("File \"belt_hashmap_test.res\", line 45, characters 7-14", Belt_Array.every(Array_data_util.range(2001, 100000), x => Belt_HashMap.has(v, x)));
   });
 });
 
+let Hashtbl;
+
 let N;
 
 let S;
@@ -80,6 +82,7 @@ let A;
 
 let So;
 
+exports.Hashtbl = Hashtbl;
 exports.N = N;
 exports.S = S;
 exports.I = I;
diff --git a/tests/tests/src/belt_hashmap_test.res b/tests/tests/src/belt_hashmap_test.res
index fe53ee54ed..d9253f3f46 100644
--- a/tests/tests/src/belt_hashmap_test.res
+++ b/tests/tests/src/belt_hashmap_test.res
@@ -1,6 +1,7 @@
 open Mocha
 open Test_utils
 
+module Hashtbl = Ocaml_Hashtbl
 module N = Belt.HashMap
 module S = Belt.Map.Int
 module I = Array_data_util
diff --git a/tests/tests/src/bs_mutable_set_test.js b/tests/tests/src/bs_mutable_set_test.js
index b895202553..68c62db52d 100644
--- a/tests/tests/src/bs_mutable_set_test.js
+++ b/tests/tests/src/bs_mutable_set_test.js
@@ -27,21 +27,21 @@ function b(loc, x) {
 
 let u = Belt_MutableSetInt.fromArray(Array_data_util.range(0, 30));
 
-b("File \"bs_mutable_set_test.res\", line 21, characters 8-15", Belt_MutableSetInt.removeCheck(u, 0));
+b("File \"bs_mutable_set_test.res\", line 22, characters 8-15", Belt_MutableSetInt.removeCheck(u, 0));
 
-b("File \"bs_mutable_set_test.res\", line 22, characters 8-15", !Belt_MutableSetInt.removeCheck(u, 0));
+b("File \"bs_mutable_set_test.res\", line 23, characters 8-15", !Belt_MutableSetInt.removeCheck(u, 0));
 
-b("File \"bs_mutable_set_test.res\", line 23, characters 8-15", Belt_MutableSetInt.removeCheck(u, 30));
+b("File \"bs_mutable_set_test.res\", line 24, characters 8-15", Belt_MutableSetInt.removeCheck(u, 30));
 
-b("File \"bs_mutable_set_test.res\", line 24, characters 8-15", Belt_MutableSetInt.removeCheck(u, 20));
+b("File \"bs_mutable_set_test.res\", line 25, characters 8-15", Belt_MutableSetInt.removeCheck(u, 20));
 
-eq("File \"bs_mutable_set_test.res\", line 25, characters 9-16", Belt_MutableSetInt.size(u), 28);
+eq("File \"bs_mutable_set_test.res\", line 26, characters 9-16", Belt_MutableSetInt.size(u), 28);
 
 let r = Array_data_util.randomRange(0, 30);
 
-b("File \"bs_mutable_set_test.res\", line 27, characters 8-15", 29 === Belt_MutableSetInt.maxUndefined(u));
+b("File \"bs_mutable_set_test.res\", line 28, characters 8-15", 29 === Belt_MutableSetInt.maxUndefined(u));
 
-b("File \"bs_mutable_set_test.res\", line 28, characters 8-15", 1 === Belt_MutableSetInt.minUndefined(u));
+b("File \"bs_mutable_set_test.res\", line 29, characters 8-15", 1 === Belt_MutableSetInt.minUndefined(u));
 
 Belt_MutableSetInt.add(u, 3);
 
@@ -49,7 +49,7 @@ for (let i = 0, i_finish = r.length; i < i_finish; ++i) {
   Belt_MutableSetInt.remove(u, r[i]);
 }
 
-b("File \"bs_mutable_set_test.res\", line 33, characters 8-15", Belt_MutableSetInt.isEmpty(u));
+b("File \"bs_mutable_set_test.res\", line 34, characters 8-15", Belt_MutableSetInt.isEmpty(u));
 
 Belt_MutableSetInt.add(u, 0);
 
@@ -59,47 +59,47 @@ Belt_MutableSetInt.add(u, 2);
 
 Belt_MutableSetInt.add(u, 0);
 
-eq("File \"bs_mutable_set_test.res\", line 38, characters 9-16", Belt_MutableSetInt.size(u), 3);
+eq("File \"bs_mutable_set_test.res\", line 39, characters 9-16", Belt_MutableSetInt.size(u), 3);
 
-b("File \"bs_mutable_set_test.res\", line 39, characters 8-15", !Belt_MutableSetInt.isEmpty(u));
+b("File \"bs_mutable_set_test.res\", line 40, characters 8-15", !Belt_MutableSetInt.isEmpty(u));
 
 for (let i$1 = 0; i$1 <= 3; ++i$1) {
   Belt_MutableSetInt.remove(u, i$1);
 }
 
-b("File \"bs_mutable_set_test.res\", line 43, characters 8-15", Belt_MutableSetInt.isEmpty(u));
+b("File \"bs_mutable_set_test.res\", line 44, characters 8-15", Belt_MutableSetInt.isEmpty(u));
 
 Belt_MutableSetInt.mergeMany(u, Array_data_util.randomRange(0, 20000));
 
 Belt_MutableSetInt.mergeMany(u, Array_data_util.randomRange(0, 200));
 
-eq("File \"bs_mutable_set_test.res\", line 46, characters 9-16", Belt_MutableSetInt.size(u), 20001);
+eq("File \"bs_mutable_set_test.res\", line 47, characters 9-16", Belt_MutableSetInt.size(u), 20001);
 
 Belt_MutableSetInt.removeMany(u, Array_data_util.randomRange(0, 200));
 
-eq("File \"bs_mutable_set_test.res\", line 48, characters 9-16", Belt_MutableSetInt.size(u), 19800);
+eq("File \"bs_mutable_set_test.res\", line 49, characters 9-16", Belt_MutableSetInt.size(u), 19800);
 
 Belt_MutableSetInt.removeMany(u, Array_data_util.randomRange(0, 1000));
 
-eq("File \"bs_mutable_set_test.res\", line 50, characters 9-16", Belt_MutableSetInt.size(u), 19000);
+eq("File \"bs_mutable_set_test.res\", line 51, characters 9-16", Belt_MutableSetInt.size(u), 19000);
 
 Belt_MutableSetInt.removeMany(u, Array_data_util.randomRange(0, 1000));
 
-eq("File \"bs_mutable_set_test.res\", line 52, characters 9-16", Belt_MutableSetInt.size(u), 19000);
+eq("File \"bs_mutable_set_test.res\", line 53, characters 9-16", Belt_MutableSetInt.size(u), 19000);
 
 Belt_MutableSetInt.removeMany(u, Array_data_util.randomRange(1000, 10000));
 
-eq("File \"bs_mutable_set_test.res\", line 54, characters 9-16", Belt_MutableSetInt.size(u), 10000);
+eq("File \"bs_mutable_set_test.res\", line 55, characters 9-16", Belt_MutableSetInt.size(u), 10000);
 
 Belt_MutableSetInt.removeMany(u, Array_data_util.randomRange(10000, 19999));
 
-eq("File \"bs_mutable_set_test.res\", line 56, characters 9-16", Belt_MutableSetInt.size(u), 1);
+eq("File \"bs_mutable_set_test.res\", line 57, characters 9-16", Belt_MutableSetInt.size(u), 1);
 
-b("File \"bs_mutable_set_test.res\", line 57, characters 8-15", Belt_MutableSetInt.has(u, 20000));
+b("File \"bs_mutable_set_test.res\", line 58, characters 8-15", Belt_MutableSetInt.has(u, 20000));
 
 Belt_MutableSetInt.removeMany(u, Array_data_util.randomRange(10000, 30000));
 
-b("File \"bs_mutable_set_test.res\", line 59, characters 8-15", Belt_MutableSetInt.isEmpty(u));
+b("File \"bs_mutable_set_test.res\", line 60, characters 8-15", Belt_MutableSetInt.isEmpty(u));
 
 let v = Belt_MutableSetInt.fromArray(Array_data_util.randomRange(1000, 2000));
 
@@ -113,9 +113,9 @@ let indeedRemoved = Belt_Array.reduce(bs, 0, (acc, x) => {
   }
 });
 
-eq("File \"bs_mutable_set_test.res\", line 72, characters 9-16", indeedRemoved, 500);
+eq("File \"bs_mutable_set_test.res\", line 73, characters 9-16", indeedRemoved, 500);
 
-eq("File \"bs_mutable_set_test.res\", line 73, characters 9-16", Belt_MutableSetInt.size(v), 501);
+eq("File \"bs_mutable_set_test.res\", line 74, characters 9-16", Belt_MutableSetInt.size(v), 501);
 
 let cs = Belt_Array.map(Array_data_util.randomRange(500, 2000), x => Belt_MutableSetInt.addCheck(v, x));
 
@@ -127,31 +127,31 @@ let indeedAded = Belt_Array.reduce(cs, 0, (acc, x) => {
   }
 });
 
-eq("File \"bs_mutable_set_test.res\", line 82, characters 9-16", indeedAded, 1000);
+eq("File \"bs_mutable_set_test.res\", line 83, characters 9-16", indeedAded, 1000);
 
-eq("File \"bs_mutable_set_test.res\", line 83, characters 9-16", Belt_MutableSetInt.size(v), 1501);
+eq("File \"bs_mutable_set_test.res\", line 84, characters 9-16", Belt_MutableSetInt.size(v), 1501);
 
-b("File \"bs_mutable_set_test.res\", line 84, characters 8-15", Belt_MutableSetInt.isEmpty(Belt_MutableSetInt.make()));
+b("File \"bs_mutable_set_test.res\", line 85, characters 8-15", Belt_MutableSetInt.isEmpty(Belt_MutableSetInt.make()));
 
-eq("File \"bs_mutable_set_test.res\", line 85, characters 9-16", Belt_MutableSetInt.minimum(v), 500);
+eq("File \"bs_mutable_set_test.res\", line 86, characters 9-16", Belt_MutableSetInt.minimum(v), 500);
 
-eq("File \"bs_mutable_set_test.res\", line 86, characters 9-16", Belt_MutableSetInt.maximum(v), 2000);
+eq("File \"bs_mutable_set_test.res\", line 87, characters 9-16", Belt_MutableSetInt.maximum(v), 2000);
 
-eq("File \"bs_mutable_set_test.res\", line 87, characters 9-16", Belt_MutableSetInt.minUndefined(v), 500);
+eq("File \"bs_mutable_set_test.res\", line 88, characters 9-16", Belt_MutableSetInt.minUndefined(v), 500);
 
-eq("File \"bs_mutable_set_test.res\", line 88, characters 9-16", Belt_MutableSetInt.maxUndefined(v), 2000);
+eq("File \"bs_mutable_set_test.res\", line 89, characters 9-16", Belt_MutableSetInt.maxUndefined(v), 2000);
 
-eq("File \"bs_mutable_set_test.res\", line 89, characters 9-16", Belt_MutableSetInt.reduce(v, 0, (x, y) => x + y | 0), 1876250);
+eq("File \"bs_mutable_set_test.res\", line 90, characters 9-16", Belt_MutableSetInt.reduce(v, 0, (x, y) => x + y | 0), 1876250);
 
-b("File \"bs_mutable_set_test.res\", line 90, characters 8-15", Belt_List.eq(Belt_MutableSetInt.toList(v), Belt_List.makeBy(1501, i => i + 500 | 0), (x, y) => x === y));
+b("File \"bs_mutable_set_test.res\", line 91, characters 8-15", Belt_List.eq(Belt_MutableSetInt.toList(v), Belt_List.makeBy(1501, i => i + 500 | 0), (x, y) => x === y));
 
-eq("File \"bs_mutable_set_test.res\", line 91, characters 9-16", Belt_MutableSetInt.toArray(v), Array_data_util.range(500, 2000));
+eq("File \"bs_mutable_set_test.res\", line 92, characters 9-16", Belt_MutableSetInt.toArray(v), Array_data_util.range(500, 2000));
 
 Belt_MutableSetInt.checkInvariantInternal(v);
 
-eq("File \"bs_mutable_set_test.res\", line 93, characters 9-16", Belt_MutableSetInt.get(v, 3), undefined);
+eq("File \"bs_mutable_set_test.res\", line 94, characters 9-16", Belt_MutableSetInt.get(v, 3), undefined);
 
-eq("File \"bs_mutable_set_test.res\", line 94, characters 9-16", Belt_MutableSetInt.get(v, 1200), 1200);
+eq("File \"bs_mutable_set_test.res\", line 95, characters 9-16", Belt_MutableSetInt.get(v, 1200), 1200);
 
 let match = Belt_MutableSetInt.split(v, 1000);
 
@@ -161,21 +161,21 @@ let bb = match$1[1];
 
 let aa = match$1[0];
 
-b("File \"bs_mutable_set_test.res\", line 96, characters 8-15", match[1]);
+b("File \"bs_mutable_set_test.res\", line 97, characters 8-15", match[1]);
 
-b("File \"bs_mutable_set_test.res\", line 97, characters 8-15", Belt_Array.eq(Belt_MutableSetInt.toArray(aa), Array_data_util.range(500, 999), (x, y) => x === y));
+b("File \"bs_mutable_set_test.res\", line 98, characters 8-15", Belt_Array.eq(Belt_MutableSetInt.toArray(aa), Array_data_util.range(500, 999), (x, y) => x === y));
 
-b("File \"bs_mutable_set_test.res\", line 98, characters 8-15", Belt_Array.eq(Belt_MutableSetInt.toArray(bb), Array_data_util.range(1001, 2000), (prim0, prim1) => prim0 === prim1));
+b("File \"bs_mutable_set_test.res\", line 99, characters 8-15", Belt_Array.eq(Belt_MutableSetInt.toArray(bb), Array_data_util.range(1001, 2000), (prim0, prim1) => prim0 === prim1));
 
-b("File \"bs_mutable_set_test.res\", line 99, characters 8-15", Belt_MutableSetInt.subset(aa, v));
+b("File \"bs_mutable_set_test.res\", line 100, characters 8-15", Belt_MutableSetInt.subset(aa, v));
 
-b("File \"bs_mutable_set_test.res\", line 100, characters 8-15", Belt_MutableSetInt.subset(bb, v));
+b("File \"bs_mutable_set_test.res\", line 101, characters 8-15", Belt_MutableSetInt.subset(bb, v));
 
-b("File \"bs_mutable_set_test.res\", line 101, characters 8-15", Belt_MutableSetInt.isEmpty(Belt_MutableSetInt.intersect(aa, bb)));
+b("File \"bs_mutable_set_test.res\", line 102, characters 8-15", Belt_MutableSetInt.isEmpty(Belt_MutableSetInt.intersect(aa, bb)));
 
 let c = Belt_MutableSetInt.removeCheck(v, 1000);
 
-b("File \"bs_mutable_set_test.res\", line 103, characters 8-15", c);
+b("File \"bs_mutable_set_test.res\", line 104, characters 8-15", c);
 
 let match$2 = Belt_MutableSetInt.split(v, 1000);
 
@@ -185,17 +185,17 @@ let bb$1 = match$3[1];
 
 let aa$1 = match$3[0];
 
-b("File \"bs_mutable_set_test.res\", line 105, characters 8-15", !match$2[1]);
+b("File \"bs_mutable_set_test.res\", line 106, characters 8-15", !match$2[1]);
 
-b("File \"bs_mutable_set_test.res\", line 106, characters 8-15", Belt_Array.eq(Belt_MutableSetInt.toArray(aa$1), Array_data_util.range(500, 999), (prim0, prim1) => prim0 === prim1));
+b("File \"bs_mutable_set_test.res\", line 107, characters 8-15", Belt_Array.eq(Belt_MutableSetInt.toArray(aa$1), Array_data_util.range(500, 999), (prim0, prim1) => prim0 === prim1));
 
-b("File \"bs_mutable_set_test.res\", line 107, characters 8-15", Belt_Array.eq(Belt_MutableSetInt.toArray(bb$1), Array_data_util.range(1001, 2000), (prim0, prim1) => prim0 === prim1));
+b("File \"bs_mutable_set_test.res\", line 108, characters 8-15", Belt_Array.eq(Belt_MutableSetInt.toArray(bb$1), Array_data_util.range(1001, 2000), (prim0, prim1) => prim0 === prim1));
 
-b("File \"bs_mutable_set_test.res\", line 108, characters 8-15", Belt_MutableSetInt.subset(aa$1, v));
+b("File \"bs_mutable_set_test.res\", line 109, characters 8-15", Belt_MutableSetInt.subset(aa$1, v));
 
-b("File \"bs_mutable_set_test.res\", line 109, characters 8-15", Belt_MutableSetInt.subset(bb$1, v));
+b("File \"bs_mutable_set_test.res\", line 110, characters 8-15", Belt_MutableSetInt.subset(bb$1, v));
 
-b("File \"bs_mutable_set_test.res\", line 110, characters 8-15", Belt_MutableSetInt.isEmpty(Belt_MutableSetInt.intersect(aa$1, bb$1)));
+b("File \"bs_mutable_set_test.res\", line 111, characters 8-15", Belt_MutableSetInt.isEmpty(Belt_MutableSetInt.intersect(aa$1, bb$1)));
 
 let aa$2 = Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 100));
 
@@ -203,19 +203,19 @@ let bb$2 = Belt_MutableSetInt.fromArray(Array_data_util.randomRange(40, 120));
 
 let cc = Belt_MutableSetInt.union(aa$2, bb$2);
 
-b("File \"bs_mutable_set_test.res\", line 120, characters 8-15", Belt_MutableSetInt.eq(cc, Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 120))));
+b("File \"bs_mutable_set_test.res\", line 121, characters 8-15", Belt_MutableSetInt.eq(cc, Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 120))));
 
-b("File \"bs_mutable_set_test.res\", line 123, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.union(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 40))));
+b("File \"bs_mutable_set_test.res\", line 124, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.union(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 40))));
 
 let dd = Belt_MutableSetInt.intersect(aa$2, bb$2);
 
-b("File \"bs_mutable_set_test.res\", line 127, characters 8-15", Belt_MutableSetInt.eq(dd, Belt_MutableSetInt.fromArray(Array_data_util.randomRange(40, 100))));
+b("File \"bs_mutable_set_test.res\", line 128, characters 8-15", Belt_MutableSetInt.eq(dd, Belt_MutableSetInt.fromArray(Array_data_util.randomRange(40, 100))));
 
-b("File \"bs_mutable_set_test.res\", line 129, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.make()));
+b("File \"bs_mutable_set_test.res\", line 130, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.make()));
 
-b("File \"bs_mutable_set_test.res\", line 136, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))), Belt_MutableSetInt.make()));
+b("File \"bs_mutable_set_test.res\", line 137, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))), Belt_MutableSetInt.make()));
 
-b("File \"bs_mutable_set_test.res\", line 142, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray([
+b("File \"bs_mutable_set_test.res\", line 143, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray([
   1,
   3,
   4,
@@ -234,15 +234,15 @@ b("File \"bs_mutable_set_test.res\", line 142, characters 8-15", Belt_MutableSet
   5
 ])));
 
-b("File \"bs_mutable_set_test.res\", line 143, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(aa$2, bb$2), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 39))));
+b("File \"bs_mutable_set_test.res\", line 144, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(aa$2, bb$2), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 39))));
 
-b("File \"bs_mutable_set_test.res\", line 144, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(bb$2, aa$2), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(101, 120))));
+b("File \"bs_mutable_set_test.res\", line 145, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(bb$2, aa$2), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(101, 120))));
 
-b("File \"bs_mutable_set_test.res\", line 146, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))));
+b("File \"bs_mutable_set_test.res\", line 147, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))));
 
-b("File \"bs_mutable_set_test.res\", line 153, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))));
+b("File \"bs_mutable_set_test.res\", line 154, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))));
 
-b("File \"bs_mutable_set_test.res\", line 161, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, -1))));
+b("File \"bs_mutable_set_test.res\", line 162, characters 8-15", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, -1))));
 
 let a0 = Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 1000));
 
@@ -256,9 +256,9 @@ let a4 = match$4[1];
 
 let a3 = match$4[0];
 
-b("File \"bs_mutable_set_test.res\", line 173, characters 8-15", Belt_MutableSetInt.eq(a1, a3));
+b("File \"bs_mutable_set_test.res\", line 174, characters 8-15", Belt_MutableSetInt.eq(a1, a3));
 
-b("File \"bs_mutable_set_test.res\", line 174, characters 8-15", Belt_MutableSetInt.eq(a2, a4));
+b("File \"bs_mutable_set_test.res\", line 175, characters 8-15", Belt_MutableSetInt.eq(a2, a4));
 
 Belt_List.forEach({
   hd: a0,
@@ -285,9 +285,9 @@ for (let i$2 = 0; i$2 <= 100000; ++i$2) {
 
 Belt_MutableSetInt.checkInvariantInternal(v$1);
 
-b("File \"bs_mutable_set_test.res\", line 188, characters 10-17", Belt_Range.every(0, 100000, i => Belt_MutableSetInt.has(v$1, i)));
+b("File \"bs_mutable_set_test.res\", line 189, characters 10-17", Belt_Range.every(0, 100000, i => Belt_MutableSetInt.has(v$1, i)));
 
-eq("File \"bs_mutable_set_test.res\", line 189, characters 5-12", Belt_MutableSetInt.size(v$1), 100001);
+eq("File \"bs_mutable_set_test.res\", line 190, characters 5-12", Belt_MutableSetInt.size(v$1), 100001);
 
 let u$1 = Belt_Array.concat(Array_data_util.randomRange(30, 100), Array_data_util.randomRange(40, 120));
 
@@ -295,15 +295,15 @@ let v$2 = Belt_MutableSetInt.make();
 
 Belt_MutableSetInt.mergeMany(v$2, u$1);
 
-eq("File \"bs_mutable_set_test.res\", line 196, characters 5-12", Belt_MutableSetInt.size(v$2), 91);
+eq("File \"bs_mutable_set_test.res\", line 197, characters 5-12", Belt_MutableSetInt.size(v$2), 91);
 
-eq("File \"bs_mutable_set_test.res\", line 197, characters 5-12", Belt_MutableSetInt.toArray(v$2), Array_data_util.range(30, 120));
+eq("File \"bs_mutable_set_test.res\", line 198, characters 5-12", Belt_MutableSetInt.toArray(v$2), Array_data_util.range(30, 120));
 
 let u$2 = Belt_Array.concat(Array_data_util.randomRange(0, 100000), Array_data_util.randomRange(0, 100));
 
 let v$3 = Belt_MutableSetInt.fromArray(u$2);
 
-eq("File \"bs_mutable_set_test.res\", line 203, characters 5-12", Belt_MutableSetInt.size(v$3), 100001);
+eq("File \"bs_mutable_set_test.res\", line 204, characters 5-12", Belt_MutableSetInt.size(v$3), 100001);
 
 let u$3 = Array_data_util.randomRange(50000, 80000);
 
@@ -311,7 +311,7 @@ for (let i$3 = 0, i_finish$1 = u$3.length; i$3 < i_finish$1; ++i$3) {
   Belt_MutableSetInt.remove(v$3, i$3);
 }
 
-eq("File \"bs_mutable_set_test.res\", line 210, characters 5-12", Belt_MutableSetInt.size(v$3), 70000);
+eq("File \"bs_mutable_set_test.res\", line 211, characters 5-12", Belt_MutableSetInt.size(v$3), 70000);
 
 let vv = Array_data_util.randomRange(0, 100000);
 
@@ -319,9 +319,9 @@ for (let i$4 = 0, i_finish$2 = vv.length; i$4 < i_finish$2; ++i$4) {
   Belt_MutableSetInt.remove(v$3, Primitive_array.get(vv, i$4));
 }
 
-eq("File \"bs_mutable_set_test.res\", line 216, characters 5-12", Belt_MutableSetInt.size(v$3), 0);
+eq("File \"bs_mutable_set_test.res\", line 217, characters 5-12", Belt_MutableSetInt.size(v$3), 0);
 
-b("File \"bs_mutable_set_test.res\", line 217, characters 4-11", Belt_MutableSetInt.isEmpty(v$3));
+b("File \"bs_mutable_set_test.res\", line 218, characters 4-11", Belt_MutableSetInt.isEmpty(v$3));
 
 let v$4 = Belt_MutableSetInt.fromArray(Belt_Array.makeBy(30, i => i));
 
@@ -329,13 +329,13 @@ Belt_MutableSetInt.remove(v$4, 30);
 
 Belt_MutableSetInt.remove(v$4, 29);
 
-b("File \"bs_mutable_set_test.res\", line 224, characters 4-11", 28 === Belt_MutableSetInt.maxUndefined(v$4));
+b("File \"bs_mutable_set_test.res\", line 225, characters 4-11", 28 === Belt_MutableSetInt.maxUndefined(v$4));
 
 Belt_MutableSetInt.remove(v$4, 0);
 
-b("File \"bs_mutable_set_test.res\", line 226, characters 4-11", 1 === Belt_MutableSetInt.minUndefined(v$4));
+b("File \"bs_mutable_set_test.res\", line 227, characters 4-11", 1 === Belt_MutableSetInt.minUndefined(v$4));
 
-eq("File \"bs_mutable_set_test.res\", line 227, characters 5-12", Belt_MutableSetInt.size(v$4), 28);
+eq("File \"bs_mutable_set_test.res\", line 228, characters 5-12", Belt_MutableSetInt.size(v$4), 28);
 
 let vv$1 = Array_data_util.randomRange(1, 28);
 
@@ -343,7 +343,7 @@ for (let i$5 = 0, i_finish$3 = vv$1.length; i$5 < i_finish$3; ++i$5) {
   Belt_MutableSetInt.remove(v$4, Primitive_array.get(vv$1, i$5));
 }
 
-eq("File \"bs_mutable_set_test.res\", line 232, characters 5-12", Belt_MutableSetInt.size(v$4), 0);
+eq("File \"bs_mutable_set_test.res\", line 233, characters 5-12", Belt_MutableSetInt.size(v$4), 0);
 
 function id(loc, x) {
   let u = Belt_MutableSetInt.fromSortedArrayUnsafe(x);
@@ -351,29 +351,29 @@ function id(loc, x) {
   b(loc, Belt_Array.every2(Belt_MutableSetInt.toArray(u), x, (prim0, prim1) => prim0 === prim1));
 }
 
-id("File \"bs_mutable_set_test.res\", line 242, characters 5-12", []);
+id("File \"bs_mutable_set_test.res\", line 243, characters 5-12", []);
 
-id("File \"bs_mutable_set_test.res\", line 243, characters 5-12", [0]);
+id("File \"bs_mutable_set_test.res\", line 244, characters 5-12", [0]);
 
-id("File \"bs_mutable_set_test.res\", line 244, characters 5-12", [
+id("File \"bs_mutable_set_test.res\", line 245, characters 5-12", [
   0,
   1
 ]);
 
-id("File \"bs_mutable_set_test.res\", line 245, characters 5-12", [
+id("File \"bs_mutable_set_test.res\", line 246, characters 5-12", [
   0,
   1,
   2
 ]);
 
-id("File \"bs_mutable_set_test.res\", line 246, characters 5-12", [
+id("File \"bs_mutable_set_test.res\", line 247, characters 5-12", [
   0,
   1,
   2,
   3
 ]);
 
-id("File \"bs_mutable_set_test.res\", line 247, characters 5-12", [
+id("File \"bs_mutable_set_test.res\", line 248, characters 5-12", [
   0,
   1,
   2,
@@ -381,7 +381,7 @@ id("File \"bs_mutable_set_test.res\", line 247, characters 5-12", [
   4
 ]);
 
-id("File \"bs_mutable_set_test.res\", line 248, characters 5-12", [
+id("File \"bs_mutable_set_test.res\", line 249, characters 5-12", [
   0,
   1,
   2,
@@ -390,7 +390,7 @@ id("File \"bs_mutable_set_test.res\", line 248, characters 5-12", [
   5
 ]);
 
-id("File \"bs_mutable_set_test.res\", line 249, characters 5-12", [
+id("File \"bs_mutable_set_test.res\", line 250, characters 5-12", [
   0,
   1,
   2,
@@ -399,7 +399,7 @@ id("File \"bs_mutable_set_test.res\", line 249, characters 5-12", [
   6
 ]);
 
-id("File \"bs_mutable_set_test.res\", line 250, characters 5-12", [
+id("File \"bs_mutable_set_test.res\", line 251, characters 5-12", [
   0,
   1,
   2,
@@ -409,7 +409,7 @@ id("File \"bs_mutable_set_test.res\", line 250, characters 5-12", [
   7
 ]);
 
-id("File \"bs_mutable_set_test.res\", line 251, characters 5-12", [
+id("File \"bs_mutable_set_test.res\", line 252, characters 5-12", [
   0,
   1,
   2,
@@ -420,7 +420,7 @@ id("File \"bs_mutable_set_test.res\", line 251, characters 5-12", [
   8
 ]);
 
-id("File \"bs_mutable_set_test.res\", line 252, characters 5-12", [
+id("File \"bs_mutable_set_test.res\", line 253, characters 5-12", [
   0,
   1,
   2,
@@ -432,7 +432,7 @@ id("File \"bs_mutable_set_test.res\", line 252, characters 5-12", [
   9
 ]);
 
-id("File \"bs_mutable_set_test.res\", line 253, characters 5-12", Array_data_util.range(0, 1000));
+id("File \"bs_mutable_set_test.res\", line 254, characters 5-12", Array_data_util.range(0, 1000));
 
 let v$5 = Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 1000));
 
@@ -446,15 +446,15 @@ for (let i$6 = 0; i$6 <= 200; ++i$6) {
   Belt_MutableSetInt.remove(v$5, i$6);
 }
 
-eq("File \"bs_mutable_set_test.res\", line 264, characters 5-12", Belt_MutableSetInt.size(copyV), 126);
+eq("File \"bs_mutable_set_test.res\", line 265, characters 5-12", Belt_MutableSetInt.size(copyV), 126);
 
-eq("File \"bs_mutable_set_test.res\", line 265, characters 5-12", Belt_MutableSetInt.toArray(copyV), Belt_Array.makeBy(126, i => (i << 3)));
+eq("File \"bs_mutable_set_test.res\", line 266, characters 5-12", Belt_MutableSetInt.toArray(copyV), Belt_Array.makeBy(126, i => (i << 3)));
 
-eq("File \"bs_mutable_set_test.res\", line 266, characters 5-12", Belt_MutableSetInt.size(v$5), 800);
+eq("File \"bs_mutable_set_test.res\", line 267, characters 5-12", Belt_MutableSetInt.size(v$5), 800);
 
-b("File \"bs_mutable_set_test.res\", line 267, characters 4-11", Belt_MutableSetInt.eq(copyV, match$5[0]));
+b("File \"bs_mutable_set_test.res\", line 268, characters 4-11", Belt_MutableSetInt.eq(copyV, match$5[0]));
 
-b("File \"bs_mutable_set_test.res\", line 268, characters 4-11", Belt_MutableSetInt.eq(cc$1, match$5[1]));
+b("File \"bs_mutable_set_test.res\", line 269, characters 4-11", Belt_MutableSetInt.eq(cc$1, match$5[1]));
 
 let v$6 = Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 1000));
 
@@ -462,9 +462,9 @@ let match$6 = Belt_MutableSetInt.split(v$6, 400);
 
 let match$7 = match$6[0];
 
-b("File \"bs_mutable_set_test.res\", line 274, characters 4-11", Belt_MutableSetInt.eq(match$7[0], Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 399))));
+b("File \"bs_mutable_set_test.res\", line 275, characters 4-11", Belt_MutableSetInt.eq(match$7[0], Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 399))));
 
-b("File \"bs_mutable_set_test.res\", line 275, characters 4-11", Belt_MutableSetInt.eq(match$7[1], Belt_MutableSetInt.fromArray(Array_data_util.randomRange(401, 1000))));
+b("File \"bs_mutable_set_test.res\", line 276, characters 4-11", Belt_MutableSetInt.eq(match$7[1], Belt_MutableSetInt.fromArray(Array_data_util.randomRange(401, 1000))));
 
 let d = Belt_MutableSetInt.fromArray(Belt_Array.map(Array_data_util.randomRange(0, 1000), x => (x << 1)));
 
@@ -472,9 +472,9 @@ let match$8 = Belt_MutableSetInt.split(d, 1001);
 
 let match$9 = match$8[0];
 
-b("File \"bs_mutable_set_test.res\", line 278, characters 4-11", Belt_MutableSetInt.eq(match$9[0], Belt_MutableSetInt.fromArray(Belt_Array.makeBy(501, x => (x << 1)))));
+b("File \"bs_mutable_set_test.res\", line 279, characters 4-11", Belt_MutableSetInt.eq(match$9[0], Belt_MutableSetInt.fromArray(Belt_Array.makeBy(501, x => (x << 1)))));
 
-b("File \"bs_mutable_set_test.res\", line 279, characters 4-11", Belt_MutableSetInt.eq(match$9[1], Belt_MutableSetInt.fromArray(Belt_Array.makeBy(500, x => 1002 + (x << 1) | 0))));
+b("File \"bs_mutable_set_test.res\", line 280, characters 4-11", Belt_MutableSetInt.eq(match$9[1], Belt_MutableSetInt.fromArray(Belt_Array.makeBy(500, x => 1002 + (x << 1) | 0))));
 
 let aa$3 = Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 100));
 
@@ -482,19 +482,19 @@ let bb$3 = Belt_MutableSetInt.fromArray(Array_data_util.randomRange(40, 120));
 
 let cc$2 = Belt_MutableSetInt.union(aa$3, bb$3);
 
-b("File \"bs_mutable_set_test.res\", line 289, characters 4-11", Belt_MutableSetInt.eq(cc$2, Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 120))));
+b("File \"bs_mutable_set_test.res\", line 290, characters 4-11", Belt_MutableSetInt.eq(cc$2, Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 120))));
 
-b("File \"bs_mutable_set_test.res\", line 292, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.union(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 40))));
+b("File \"bs_mutable_set_test.res\", line 293, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.union(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 40))));
 
 let dd$1 = Belt_MutableSetInt.intersect(aa$3, bb$3);
 
-b("File \"bs_mutable_set_test.res\", line 296, characters 4-11", Belt_MutableSetInt.eq(dd$1, Belt_MutableSetInt.fromArray(Array_data_util.randomRange(40, 100))));
+b("File \"bs_mutable_set_test.res\", line 297, characters 4-11", Belt_MutableSetInt.eq(dd$1, Belt_MutableSetInt.fromArray(Array_data_util.randomRange(40, 100))));
 
-b("File \"bs_mutable_set_test.res\", line 298, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.make()));
+b("File \"bs_mutable_set_test.res\", line 299, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.make()));
 
-b("File \"bs_mutable_set_test.res\", line 302, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))), Belt_MutableSetInt.make()));
+b("File \"bs_mutable_set_test.res\", line 303, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))), Belt_MutableSetInt.make()));
 
-b("File \"bs_mutable_set_test.res\", line 305, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray([
+b("File \"bs_mutable_set_test.res\", line 306, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.intersect(Belt_MutableSetInt.fromArray([
   1,
   3,
   4,
@@ -513,20 +513,22 @@ b("File \"bs_mutable_set_test.res\", line 305, characters 4-11", Belt_MutableSet
   5
 ])));
 
-b("File \"bs_mutable_set_test.res\", line 306, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(aa$3, bb$3), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 39))));
+b("File \"bs_mutable_set_test.res\", line 307, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(aa$3, bb$3), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 39))));
 
-b("File \"bs_mutable_set_test.res\", line 307, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(bb$3, aa$3), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(101, 120))));
+b("File \"bs_mutable_set_test.res\", line 308, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(bb$3, aa$3), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(101, 120))));
 
-b("File \"bs_mutable_set_test.res\", line 309, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))));
+b("File \"bs_mutable_set_test.res\", line 310, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))));
 
-b("File \"bs_mutable_set_test.res\", line 316, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))));
+b("File \"bs_mutable_set_test.res\", line 317, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(21, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20))));
 
-b("File \"bs_mutable_set_test.res\", line 324, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, -1))));
+b("File \"bs_mutable_set_test.res\", line 325, characters 4-11", Belt_MutableSetInt.eq(Belt_MutableSetInt.diff(Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 20)), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, 40))), Belt_MutableSetInt.fromArray(Array_data_util.randomRange(0, -1))));
 
 Mt.from_pair_suites("Bs_mutable_set_test", suites.contents);
 
 let N;
 
+let $$Array;
+
 let I;
 
 let R;
@@ -550,6 +552,7 @@ exports.test_id = test_id;
 exports.eq = eq;
 exports.b = b;
 exports.N = N;
+exports.$$Array = $$Array;
 exports.I = I;
 exports.R = R;
 exports.A = A;
diff --git a/tests/tests/src/bs_mutable_set_test.res b/tests/tests/src/bs_mutable_set_test.res
index 0c89a357d4..bfab257666 100644
--- a/tests/tests/src/bs_mutable_set_test.res
+++ b/tests/tests/src/bs_mutable_set_test.res
@@ -4,6 +4,7 @@ let eq = (loc, x, y) => Mt.eq_suites(~test_id, ~suites, loc, x, y)
 let b = (loc, x) => Mt.bool_suites(~test_id, ~suites, loc, x)
 
 module N = Belt.MutableSet.Int
+module Array = Ocaml_Array
 
 module I = Array_data_util
 module R = Belt.Range
diff --git a/tests/tests/src/chn_test.js b/tests/tests/src/chn_test.js
index ac33b6aabe..97e5f6699e 100644
--- a/tests/tests/src/chn_test.js
+++ b/tests/tests/src/chn_test.js
@@ -41,7 +41,7 @@ function convert(s) {
       RE_EXN_ID: "Assert_failure",
       _1: [
         "chn_test.res",
-        23,
+        24,
         16
       ],
       Error: new Error()
@@ -49,9 +49,9 @@ function convert(s) {
   }));
 }
 
-eq("File \"chn_test.res\", line 31, characters 4-11", "你好，\n世界", "你好，\n世界");
+eq("File \"chn_test.res\", line 32, characters 4-11", "你好，\n世界", "你好，\n世界");
 
-eq("File \"chn_test.res\", line 37, characters 4-11", convert("汉字是世界上最美丽的character"), {
+eq("File \"chn_test.res\", line 38, characters 4-11", convert("汉字是世界上最美丽的character"), {
   hd: 27721,
   tl: {
     hd: 23383,
@@ -110,7 +110,7 @@ eq("File \"chn_test.res\", line 37, characters 4-11", convert("汉字是世界
   }
 });
 
-eq("File \"chn_test.res\", line 61, characters 5-12", convert("\x3f\x3fa"), {
+eq("File \"chn_test.res\", line 62, characters 5-12", convert("\x3f\x3fa"), {
   hd: 63,
   tl: {
     hd: 63,
@@ -121,7 +121,7 @@ eq("File \"chn_test.res\", line 61, characters 5-12", convert("\x3f\x3fa"), {
   }
 });
 
-eq("File \"chn_test.res\", line 62, characters 5-12", convert("??a"), {
+eq("File \"chn_test.res\", line 63, characters 5-12", convert("??a"), {
   hd: 63,
   tl: {
     hd: 63,
@@ -132,7 +132,7 @@ eq("File \"chn_test.res\", line 62, characters 5-12", convert("??a"), {
   }
 });
 
-eq("File \"chn_test.res\", line 63, characters 5-12", convert("\u003f\x3fa"), {
+eq("File \"chn_test.res\", line 64, characters 5-12", convert("\u003f\x3fa"), {
   hd: 63,
   tl: {
     hd: 63,
@@ -143,7 +143,7 @@ eq("File \"chn_test.res\", line 63, characters 5-12", convert("\u003f\x3fa"), {
   }
 });
 
-eq("File \"chn_test.res\", line 64, characters 5-12", convert("🚀🚀a"), {
+eq("File \"chn_test.res\", line 65, characters 5-12", convert("🚀🚀a"), {
   hd: 128640,
   tl: {
     hd: 128640,
@@ -154,7 +154,7 @@ eq("File \"chn_test.res\", line 64, characters 5-12", convert("🚀🚀a"), {
   }
 });
 
-eq("File \"chn_test.res\", line 65, characters 5-12", convert("\uD83D\uDE80a"), {
+eq("File \"chn_test.res\", line 66, characters 5-12", convert("\uD83D\uDE80a"), {
   hd: 128640,
   tl: {
     hd: 97,
@@ -162,7 +162,7 @@ eq("File \"chn_test.res\", line 65, characters 5-12", convert("\uD83D\uDE80a"),
   }
 });
 
-eq("File \"chn_test.res\", line 66, characters 5-12", convert("\uD83D\uDE80\x3f"), {
+eq("File \"chn_test.res\", line 67, characters 5-12", convert("\uD83D\uDE80\x3f"), {
   hd: 128640,
   tl: {
     hd: 63,
@@ -170,7 +170,7 @@ eq("File \"chn_test.res\", line 66, characters 5-12", convert("\uD83D\uDE80\x3f"
   }
 });
 
-eq("File \"chn_test.res\", line 70, characters 5-12", convert("\uD83D\uDE80\uD83D\uDE80a"), {
+eq("File \"chn_test.res\", line 71, characters 5-12", convert("\uD83D\uDE80\uD83D\uDE80a"), {
   hd: 128640,
   tl: {
     hd: 128640,
@@ -183,16 +183,16 @@ eq("File \"chn_test.res\", line 70, characters 5-12", convert("\uD83D\uDE80\uD83
 
 eq("No inline string length", "\uD83D\uDE80\0".length, 3);
 
-eq("File \"chn_test.res\", line 77, characters 4-11", "\uD83D\uDE80\0".codePointAt(0), 128640);
+eq("File \"chn_test.res\", line 78, characters 4-11", "\uD83D\uDE80\0".codePointAt(0), 128640);
 
-eq("File \"chn_test.res\", line 82, characters 5-12", "🚀".codePointAt(0), 128640);
+eq("File \"chn_test.res\", line 83, characters 5-12", "🚀".codePointAt(0), 128640);
 
-eq("File \"chn_test.res\", line 87, characters 5-12", convert("\uD83D\uDE80"), {
+eq("File \"chn_test.res\", line 88, characters 5-12", convert("\uD83D\uDE80"), {
   hd: 128640,
   tl: /* [] */0
 });
 
-eq("File \"chn_test.res\", line 88, characters 5-12", convert("\uD83D\uDE80\uD83D\uDE80"), {
+eq("File \"chn_test.res\", line 89, characters 5-12", convert("\uD83D\uDE80\uD83D\uDE80"), {
   hd: 128640,
   tl: {
     hd: 128640,
@@ -200,7 +200,7 @@ eq("File \"chn_test.res\", line 88, characters 5-12", convert("\uD83D\uDE80\uD83
   }
 });
 
-eq("File \"chn_test.res\", line 89, characters 5-12", convert(" \b\t\n\v\f\ra"), {
+eq("File \"chn_test.res\", line 90, characters 5-12", convert(" \b\t\n\v\f\ra"), {
   hd: 32,
   tl: {
     hd: 8,
@@ -226,7 +226,7 @@ eq("File \"chn_test.res\", line 89, characters 5-12", convert(" \b\t\n\v\f\ra"),
   }
 });
 
-eq("File \"chn_test.res\", line 95, characters 5-12", convert(" \b\t\n\v\f\r\"'\\\0a"), {
+eq("File \"chn_test.res\", line 96, characters 5-12", convert(" \b\t\n\v\f\r\"'\\\0a"), {
   hd: 32,
   tl: {
     hd: 8,
@@ -266,6 +266,9 @@ eq("File \"chn_test.res\", line 95, characters 5-12", convert(" \b\t\n\v\f\r\"'\
 
 Mt.from_pair_suites("Chn_test", suites.contents);
 
+let $$String;
+
+exports.$$String = $$String;
 exports.suites = suites;
 exports.test_id = test_id;
 exports.eq = eq;
diff --git a/tests/tests/src/chn_test.res b/tests/tests/src/chn_test.res
index 9e9b743245..cb11cdaabd 100644
--- a/tests/tests/src/chn_test.res
+++ b/tests/tests/src/chn_test.res
@@ -1,4 +1,5 @@
 open Belt
+module String = Ocaml_String
 
 let suites: ref<Mt.pair_suites> = ref(list{})
 let test_id = ref(0)
diff --git a/tests/tests/src/const_block_test.res b/tests/tests/src/const_block_test.res
index 7d6b9fc1cf..d28cfe5a08 100644
--- a/tests/tests/src/const_block_test.res
+++ b/tests/tests/src/const_block_test.res
@@ -1,3 +1,5 @@
+module Array = Ocaml_Array
+
 let a = [0., 1., 2.]
 let b = [0, 1, 2]
 let c = [0, 1, 2, 3, 4, 5]
diff --git a/tests/tests/src/cps_test.js b/tests/tests/src/cps_test.js
index 888da302e1..6136c08066 100644
--- a/tests/tests/src/cps_test.js
+++ b/tests/tests/src/cps_test.js
@@ -3,7 +3,6 @@
 
 let Mt = require("./mt.js");
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 function test() {
   let v = {
@@ -34,7 +33,7 @@ function test_closure() {
   };
   let arr = Belt_Array.make(6, x => x);
   for (let i = 0; i <= 5; ++i) {
-    Primitive_array.set(arr, i, param => i);
+    arr[i] = param => i;
   }
   Belt_Array.forEach(arr, i => {
     v.contents = v.contents + i(0) | 0;
@@ -49,7 +48,7 @@ function test_closure2() {
   let arr = Belt_Array.make(6, x => x);
   for (let i = 0; i <= 5; ++i) {
     let j = i + i | 0;
-    Primitive_array.set(arr, i, param => j);
+    arr[i] = param => j;
   }
   Belt_Array.forEach(arr, i => {
     v.contents = v.contents + i(0) | 0;
diff --git a/tests/tests/src/custom_error_test.js b/tests/tests/src/custom_error_test.js
index 37400226b7..12e8246a47 100644
--- a/tests/tests/src/custom_error_test.js
+++ b/tests/tests/src/custom_error_test.js
@@ -1,7 +1,7 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 'use strict';
 
-let Js_exn = require("rescript/lib/js/Js_exn.js");
+let Exn = require("rescript/lib/js/Exn.js");
 let Primitive_exceptions = require("rescript/lib/js/Primitive_exceptions.js");
 
 function test_js_error() {
@@ -10,7 +10,7 @@ function test_js_error() {
     e = JSON.parse(" {\"x\" : }");
   } catch (raw_err) {
     let err = Primitive_exceptions.internalToException(raw_err);
-    if (err.RE_EXN_ID === Js_exn.$$Error) {
+    if (err.RE_EXN_ID === Exn.$$Error) {
       console.log(err._1.stack);
       return;
     }
@@ -24,7 +24,7 @@ function test_js_error2() {
     return JSON.parse(" {\"x\" : }");
   } catch (raw_e) {
     let e = Primitive_exceptions.internalToException(raw_e);
-    if (e.RE_EXN_ID === Js_exn.$$Error) {
+    if (e.RE_EXN_ID === Exn.$$Error) {
       console.log(e._1.stack);
       throw e;
     }
@@ -38,7 +38,7 @@ function example1() {
     v = JSON.parse(" {\"x\"  }");
   } catch (raw_err) {
     let err = Primitive_exceptions.internalToException(raw_err);
-    if (err.RE_EXN_ID === Js_exn.$$Error) {
+    if (err.RE_EXN_ID === Exn.$$Error) {
       console.log(err._1.stack);
       return;
     }
@@ -52,7 +52,7 @@ function example2() {
     return JSON.parse(" {\"x\"}");
   } catch (raw_exn) {
     let exn = Primitive_exceptions.internalToException(raw_exn);
-    if (exn.RE_EXN_ID === Js_exn.$$Error) {
+    if (exn.RE_EXN_ID === Exn.$$Error) {
       return;
     }
     throw exn;
diff --git a/tests/tests/src/equal_exception_test.js b/tests/tests/src/equal_exception_test.js
index 5f17e0185b..4179bf287a 100644
--- a/tests/tests/src/equal_exception_test.js
+++ b/tests/tests/src/equal_exception_test.js
@@ -15,7 +15,7 @@ function is_equal() {
     RE_EXN_ID: "Assert_failure",
     _1: [
       "equal_exception_test.res",
-      4,
+      6,
       2
     ],
     Error: new Error()
@@ -116,7 +116,7 @@ if (Primitive_object.equal(e, {
     RE_EXN_ID: "Assert_failure",
     _1: [
       "equal_exception_test.res",
-      45,
+      47,
       0
     ],
     Error: new Error()
@@ -128,7 +128,7 @@ if (Not_found === "Not_found" !== false) {
     RE_EXN_ID: "Assert_failure",
     _1: [
       "equal_exception_test.res",
-      46,
+      48,
       0
     ],
     Error: new Error()
@@ -137,6 +137,9 @@ if (Not_found === "Not_found" !== false) {
 
 Mt.from_suites("exception", suites);
 
+let $$String;
+
+exports.$$String = $$String;
 exports.v = v;
 exports.is_equal = is_equal;
 exports.is_exception = is_exception;
diff --git a/tests/tests/src/equal_exception_test.res b/tests/tests/src/equal_exception_test.res
index dd7d77e301..5b673bf1fc 100644
--- a/tests/tests/src/equal_exception_test.res
+++ b/tests/tests/src/equal_exception_test.res
@@ -1,3 +1,5 @@
+module String = Ocaml_String
+
 let v = "gso"
 
 let is_equal = () => {
diff --git a/tests/tests/src/exception_raise_test.js b/tests/tests/src/exception_raise_test.js
index 622bf8e091..4b7f7b2fba 100644
--- a/tests/tests/src/exception_raise_test.js
+++ b/tests/tests/src/exception_raise_test.js
@@ -2,7 +2,7 @@
 'use strict';
 
 let Mt = require("./mt.js");
-let Js_exn = require("rescript/lib/js/Js_exn.js");
+let Exn = require("rescript/lib/js/Exn.js");
 let Belt_List = require("rescript/lib/js/Belt_List.js");
 let Primitive_exceptions = require("rescript/lib/js/Primitive_exceptions.js");
 
@@ -90,7 +90,7 @@ try {
   a0 = (function (){throw 2} ());
 } catch (raw_x$3) {
   let x$3 = Primitive_exceptions.internalToException(raw_x$3);
-  if (x$3.RE_EXN_ID === A || x$3.RE_EXN_ID === Js_exn.$$Error) {
+  if (x$3.RE_EXN_ID === A || x$3.RE_EXN_ID === Exn.$$Error) {
     a0 = x$3._1;
   } else {
     throw {
@@ -145,7 +145,7 @@ let suites = {
       hd: [
         "File \"exception_raise_test.res\", line 123, characters 6-13",
         () => {
-          if (a1.RE_EXN_ID === Js_exn.$$Error) {
+          if (a1.RE_EXN_ID === Exn.$$Error) {
             return {
               TAG: "Eq",
               _0: a1._1,
@@ -180,7 +180,7 @@ try {
   ((()=>{throw 2})());
 } catch (raw_e$2) {
   let e = Primitive_exceptions.internalToException(raw_e$2);
-  eq("File \"exception_raise_test.res\", line 137, characters 10-17", Js_exn.asJsExn(e) !== undefined, true);
+  eq("File \"exception_raise_test.res\", line 137, characters 10-17", Exn.asJsExn(e) !== undefined, true);
 }
 
 try {
@@ -190,7 +190,7 @@ try {
   };
 } catch (raw_e$3) {
   let e$1 = Primitive_exceptions.internalToException(raw_e$3);
-  eq("File \"exception_raise_test.res\", line 141, characters 10-17", Js_exn.asJsExn(e$1) !== undefined, false);
+  eq("File \"exception_raise_test.res\", line 141, characters 10-17", Exn.asJsExn(e$1) !== undefined, false);
 }
 
 function fff0(x, g) {
diff --git a/tests/tests/src/exception_value_test.js b/tests/tests/src/exception_value_test.js
index d84820c514..dccedce368 100644
--- a/tests/tests/src/exception_value_test.js
+++ b/tests/tests/src/exception_value_test.js
@@ -1,7 +1,7 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 'use strict';
 
-let Js_exn = require("rescript/lib/js/Js_exn.js");
+let Exn = require("rescript/lib/js/Exn.js");
 let Primitive_exceptions = require("rescript/lib/js/Primitive_exceptions.js");
 
 function f() {
@@ -61,7 +61,7 @@ function test_js_error2() {
     return JSON.parse(" {\"x\" : }");
   } catch (raw_e) {
     let e = Primitive_exceptions.internalToException(raw_e);
-    if (e.RE_EXN_ID === Js_exn.$$Error) {
+    if (e.RE_EXN_ID === Exn.$$Error) {
       console.log(e._1.stack);
       throw e;
     }
diff --git a/tests/tests/src/ext_pervasives_test.res b/tests/tests/src/ext_pervasives_test.res
index daea9db334..a70b890a87 100644
--- a/tests/tests/src/ext_pervasives_test.res
+++ b/tests/tests/src/ext_pervasives_test.res
@@ -22,6 +22,8 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
 
+module String = Ocaml_String
+
 external reraise: exn => 'a = "%raise"
 
 let finally = (v, action, f) =>
diff --git a/tests/tests/src/flexible_array_test.js b/tests/tests/src/flexible_array_test.js
index d8a611d854..34b52f9366 100644
--- a/tests/tests/src/flexible_array_test.js
+++ b/tests/tests/src/flexible_array_test.js
@@ -145,7 +145,7 @@ function lorem(tr) {
     RE_EXN_ID: "Assert_failure",
     _1: [
       "flexible_array_test.res",
-      80,
+      82,
       9
     ],
     Error: new Error()
@@ -303,7 +303,7 @@ if (!$eq$tilde(sort(u), [
     RE_EXN_ID: "Assert_failure",
     _1: [
       "flexible_array_test.res",
-      184,
+      186,
       2
     ],
     Error: new Error()
@@ -314,6 +314,9 @@ let v = Belt_Array.init(500, i => 500 - i | 0);
 
 $eq$tilde(sort(of_array(v)), Belt_Array.init(500, i => i + 1 | 0));
 
+let $$Array;
+
+exports.$$Array = $$Array;
 exports.sub = sub;
 exports.update = update;
 exports.$$delete = $$delete;
diff --git a/tests/tests/src/flexible_array_test.res b/tests/tests/src/flexible_array_test.res
index 5508abf8bd..0704e270a8 100644
--- a/tests/tests/src/flexible_array_test.res
+++ b/tests/tests/src/flexible_array_test.res
@@ -1,3 +1,5 @@
+module Array = Ocaml_Array
+
 type rec tree<'a> =
   | Lf
   | Br('a, tree<'a>, tree<'a>)
diff --git a/tests/tests/src/for_loop_test.js b/tests/tests/src/for_loop_test.js
index ddf65b2f77..4dfe8ec842 100644
--- a/tests/tests/src/for_loop_test.js
+++ b/tests/tests/src/for_loop_test.js
@@ -3,7 +3,6 @@
 
 let Belt_List = require("rescript/lib/js/Belt_List.js");
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 function for_3(x) {
   let v = {
@@ -12,9 +11,9 @@ function for_3(x) {
   let arr = Belt_Array.map(x, param => (() => {}));
   for (let i = 0, i_finish = x.length; i < i_finish; ++i) {
     let j = (i << 1);
-    Primitive_array.set(arr, i, () => {
+    arr[i] = () => {
       v.contents = v.contents + j | 0;
-    });
+    };
   }
   Belt_Array.forEach(arr, x => x());
   return v.contents;
@@ -28,9 +27,9 @@ function for_4(x) {
   for (let i = 0, i_finish = x.length; i < i_finish; ++i) {
     let j = (i << 1);
     let k = (j << 1);
-    Primitive_array.set(arr, i, () => {
+    arr[i] = () => {
       v.contents = v.contents + k | 0;
-    });
+    };
   }
   Belt_Array.forEach(arr, x => x());
   return v.contents;
@@ -43,9 +42,9 @@ function for_5(x, u) {
   let arr = Belt_Array.map(x, param => (() => {}));
   for (let i = 0, i_finish = x.length; i < i_finish; ++i) {
     let k = Math.imul((u << 1), u);
-    Primitive_array.set(arr, i, () => {
+    arr[i] = () => {
       v.contents = v.contents + k | 0;
-    });
+    };
   }
   Belt_Array.forEach(arr, x => x());
   return v.contents;
@@ -73,9 +72,9 @@ function for_6(x, u) {
       let k = Math.imul((u << 1), u);
       let h = (v5.contents << 1);
       v2.contents = v2.contents + 1 | 0;
-      Primitive_array.set(arr, i, () => {
+      arr[i] = () => {
         v.contents = (((((v.contents + k | 0) + v2.contents | 0) + v4.contents | 0) + v5.contents | 0) + h | 0) + u | 0;
-      });
+      };
     }
     inspect_3 = v2.contents;
   }
@@ -95,9 +94,9 @@ function for_7() {
   let arr = Belt_Array.make(21, () => {});
   for (let i = 0; i <= 6; ++i) {
     for (let j = 0; j <= 2; ++j) {
-      Primitive_array.set(arr, Math.imul(i, 3) + j | 0, () => {
+      arr[Math.imul(i, 3) + j | 0] = () => {
         v.contents = (v.contents + i | 0) + j | 0;
-      });
+      };
     }
   }
   Belt_Array.forEach(arr, f => f());
@@ -113,9 +112,9 @@ function for_8() {
     let k = (i << 1);
     for (let j = 0; j <= 2; ++j) {
       let h = i + j | 0;
-      Primitive_array.set(arr, Math.imul(i, 3) + j | 0, () => {
+      arr[Math.imul(i, 3) + j | 0] = () => {
         v.contents = (((v.contents + i | 0) + j | 0) + h | 0) + k | 0;
-      });
+      };
     }
   }
   Belt_Array.forEach(arr, f => f());
@@ -148,13 +147,13 @@ function for_9() {
     for (let j = 0; j <= 1; ++j) {
       v$1.contents = v$1.contents + 1 | 0;
       collect(v$1.contents);
-      Primitive_array.set(arr, (i << 1) + j | 0, () => {
+      arr[(i << 1) + j | 0] = () => {
         vv.contents = vv.contents + v$1.contents | 0;
-      });
+      };
     }
-    Primitive_array.set(arr2, i, () => {
+    arr2[i] = () => {
       vv2.contents = vv2.contents + v$1.contents | 0;
-    });
+    };
   }
   Belt_Array.forEach(arr, f => f());
   Belt_Array.forEach(arr2, f => f());
diff --git a/tests/tests/src/hash_test.js b/tests/tests/src/hash_test.js
index 49dcf1992b..d0573d3860 100644
--- a/tests/tests/src/hash_test.js
+++ b/tests/tests/src/hash_test.js
@@ -2,9 +2,9 @@
 'use strict';
 
 let Mt = require("./mt.js");
-let Hashtbl = require("rescript/lib/js/Hashtbl.js");
 let Mt_global = require("./mt_global.js");
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
+let Ocaml_Hashtbl = require("./ocaml_compat/Ocaml_Hashtbl.js");
 
 let suites = {
   contents: /* [] */0
@@ -60,19 +60,22 @@ function normalize(x) {
 }
 
 function caml_hash(x) {
-  return Hashtbl.hash(x) & 1073741823;
+  return Ocaml_Hashtbl.hash(x) & 1073741823;
 }
 
-eq("File \"hash_test.res\", line 46, characters 12-19", Belt_Array.map(test_strings, caml_hash), test_strings_hash_results);
+eq("File \"hash_test.res\", line 48, characters 12-19", Belt_Array.map(test_strings, caml_hash), test_strings_hash_results);
 
-eq("File \"hash_test.res\", line 48, characters 12-19", Hashtbl.hash(0) & 1073741823, 129913994);
+eq("File \"hash_test.res\", line 50, characters 12-19", Ocaml_Hashtbl.hash(0) & 1073741823, 129913994);
 
-eq("File \"hash_test.res\", line 50, characters 12-19", Hashtbl.hash("x") & 1073741823, 780510073);
+eq("File \"hash_test.res\", line 52, characters 12-19", Ocaml_Hashtbl.hash("x") & 1073741823, 780510073);
 
-eq("File \"hash_test.res\", line 52, characters 12-19", Hashtbl.hash("xy") & 1073741823, 194127723);
+eq("File \"hash_test.res\", line 54, characters 12-19", Ocaml_Hashtbl.hash("xy") & 1073741823, 194127723);
 
 Mt.from_pair_suites("Hash_test", suites.contents);
 
+let Hashtbl;
+
+exports.Hashtbl = Hashtbl;
 exports.suites = suites;
 exports.test_id = test_id;
 exports.eq = eq;
diff --git a/tests/tests/src/hash_test.res b/tests/tests/src/hash_test.res
index ba578bbb28..86a1150475 100644
--- a/tests/tests/src/hash_test.res
+++ b/tests/tests/src/hash_test.res
@@ -1,5 +1,7 @@
 open Belt
 
+module Hashtbl = Ocaml_Hashtbl
+
 let suites: ref<Mt.pair_suites> = ref(list{})
 let test_id = ref(0)
 let eq = (f, x, y) => Mt_global.collect_eq(test_id, suites, f, x, y)
diff --git a/tests/tests/src/inline_regression_test.js b/tests/tests/src/inline_regression_test.js
index 60abed5b40..ca32d92e24 100644
--- a/tests/tests/src/inline_regression_test.js
+++ b/tests/tests/src/inline_regression_test.js
@@ -54,6 +54,9 @@ let suites = {
 
 Mt.from_pair_suites("Inline_regression_test", suites);
 
+let $$String;
+
+exports.$$String = $$String;
 exports.generic_basename = generic_basename;
 exports.basename = basename;
 exports.suites = suites;
diff --git a/tests/tests/src/inline_regression_test.res b/tests/tests/src/inline_regression_test.res
index 4b197bf34b..ce53ef4958 100644
--- a/tests/tests/src/inline_regression_test.res
+++ b/tests/tests/src/inline_regression_test.res
@@ -1,3 +1,5 @@
+module String = Ocaml_String
+
 let generic_basename = (is_dir_sep, current_dir_name, name) => {
   let rec find_end = n =>
     if n < 0 {
diff --git a/tests/tests/src/int_overflow_test.js b/tests/tests/src/int_overflow_test.js
index 68ae7452db..b484e987bd 100644
--- a/tests/tests/src/int_overflow_test.js
+++ b/tests/tests/src/int_overflow_test.js
@@ -92,7 +92,7 @@ Mt.from_pair_suites("Int_overflow_test", {
             ],
             tl: {
               hd: [
-                "File \"int_overflow_test.res\", line 72, characters 5-12",
+                "File \"int_overflow_test.res\", line 74, characters 5-12",
                 () => ({
                   TAG: "Eq",
                   _0: hash_variant2("xxyyzzuuxxzzyy00112233"),
@@ -101,7 +101,7 @@ Mt.from_pair_suites("Int_overflow_test", {
               ],
               tl: {
                 hd: [
-                  "File \"int_overflow_test.res\", line 73, characters 5-12",
+                  "File \"int_overflow_test.res\", line 75, characters 5-12",
                   () => ({
                     TAG: "Eq",
                     _0: hash_variant2("xxyyzxzzyy"),
@@ -128,7 +128,7 @@ Mt.from_pair_suites("Int_overflow_test", {
                     ],
                     tl: {
                       hd: [
-                        "File \"int_overflow_test.res\", line 76, characters 5-12",
+                        "File \"int_overflow_test.res\", line 78, characters 5-12",
                         () => ({
                           TAG: "Eq",
                           _0: Number("3") | 0,
@@ -137,7 +137,7 @@ Mt.from_pair_suites("Int_overflow_test", {
                       ],
                       tl: {
                         hd: [
-                          "File \"int_overflow_test.res\", line 78, characters 5-12",
+                          "File \"int_overflow_test.res\", line 80, characters 5-12",
                           () => ({
                             TAG: "Eq",
                             _0: Number("3.2") | 0,
@@ -158,10 +158,13 @@ Mt.from_pair_suites("Int_overflow_test", {
   }
 });
 
+let $$String;
+
 let max_int = 2147483647;
 
 let min_int = -2147483648;
 
+exports.$$String = $$String;
 exports.max_int = max_int;
 exports.min_int = min_int;
 exports.hash_variant = hash_variant;
diff --git a/tests/tests/src/int_overflow_test.res b/tests/tests/src/int_overflow_test.res
index 018a004720..8a949d089f 100644
--- a/tests/tests/src/int_overflow_test.res
+++ b/tests/tests/src/int_overflow_test.res
@@ -1,5 +1,7 @@
 @@warning("-107")
 
+module String = Ocaml_String
+
 let max_int = 2147483647 // 0x80000000
 let min_int = -2147483648 // 0x7FFFFFFF
 
diff --git a/tests/tests/src/js_exception_catch_test.js b/tests/tests/src/js_exception_catch_test.js
index 54f13628b4..60a773a8a0 100644
--- a/tests/tests/src/js_exception_catch_test.js
+++ b/tests/tests/src/js_exception_catch_test.js
@@ -2,7 +2,7 @@
 'use strict';
 
 let Mt = require("./mt.js");
-let Js_exn = require("rescript/lib/js/Js_exn.js");
+let Exn = require("rescript/lib/js/Exn.js");
 let Pervasives = require("rescript/lib/js/Pervasives.js");
 let Primitive_exceptions = require("rescript/lib/js/Primitive_exceptions.js");
 
@@ -57,7 +57,7 @@ try {
   exit = 1;
 } catch (raw_x) {
   let x = Primitive_exceptions.internalToException(raw_x);
-  if (x.RE_EXN_ID === Js_exn.$$Error) {
+  if (x.RE_EXN_ID === Exn.$$Error) {
     add_test("File \"js_exception_catch_test.res\", line 18, characters 37-44", () => ({
       TAG: "Ok",
       _0: true
@@ -108,7 +108,7 @@ function test(f) {
       } else {
         return "C";
       }
-    } else if (e.RE_EXN_ID === Js_exn.$$Error) {
+    } else if (e.RE_EXN_ID === Exn.$$Error) {
       return "Js_error";
     } else {
       return "Any";
@@ -170,7 +170,7 @@ eq("File \"js_exception_catch_test.res\", line 52, characters 5-12", test(() =>
   };
 }), "C_any");
 
-eq("File \"js_exception_catch_test.res\", line 53, characters 5-12", test(() => Js_exn.raiseError("x")), "Js_error");
+eq("File \"js_exception_catch_test.res\", line 53, characters 5-12", test(() => Exn.raiseError("x")), "Js_error");
 
 eq("File \"js_exception_catch_test.res\", line 54, characters 5-12", test(() => Pervasives.failwith("x")), "Any");
 
diff --git a/tests/tests/src/js_json_test.js b/tests/tests/src/js_json_test.js
index 26c369b56b..c4ca3be08c 100644
--- a/tests/tests/src/js_json_test.js
+++ b/tests/tests/src/js_json_test.js
@@ -53,7 +53,7 @@ function true_(loc) {
 
 let v = JSON.parse(" { \"x\" : [1, 2, 3 ] } ");
 
-add_test("File \"js_json_test.res\", line 22, characters 11-18", () => {
+add_test("File \"js_json_test.res\", line 23, characters 11-18", () => {
   let ty = Js_json.classify(v);
   if (typeof ty !== "object") {
     return {
@@ -94,7 +94,7 @@ add_test("File \"js_json_test.res\", line 22, characters 11-18", () => {
         RE_EXN_ID: "Assert_failure",
         _1: [
           "js_json_test.res",
-          38,
+          39,
           21
         ],
         Error: new Error()
@@ -107,7 +107,7 @@ add_test("File \"js_json_test.res\", line 22, characters 11-18", () => {
       RE_EXN_ID: "Assert_failure",
       _1: [
         "js_json_test.res",
-        38,
+        39,
         21
       ],
       Error: new Error()
@@ -119,7 +119,7 @@ add_test("File \"js_json_test.res\", line 22, characters 11-18", () => {
   };
 });
 
-eq("File \"js_json_test.res\", line 50, characters 5-12", Js_json.test(v, "Object"), true);
+eq("File \"js_json_test.res\", line 51, characters 5-12", Js_json.test(v, "Object"), true);
 
 let json = JSON.parse(JSON.stringify(null));
 
@@ -127,20 +127,20 @@ let ty = Js_json.classify(json);
 
 if (typeof ty !== "object") {
   if (ty === "JSONNull") {
-    add_test("File \"js_json_test.res\", line 57, characters 24-31", () => ({
+    add_test("File \"js_json_test.res\", line 58, characters 24-31", () => ({
       TAG: "Ok",
       _0: true
     }));
   } else {
     console.log(ty);
-    add_test("File \"js_json_test.res\", line 60, characters 11-18", () => ({
+    add_test("File \"js_json_test.res\", line 61, characters 11-18", () => ({
       TAG: "Ok",
       _0: false
     }));
   }
 } else {
   console.log(ty);
-  add_test("File \"js_json_test.res\", line 60, characters 11-18", () => ({
+  add_test("File \"js_json_test.res\", line 61, characters 11-18", () => ({
     TAG: "Ok",
     _0: false
   }));
@@ -151,14 +151,14 @@ let json$1 = JSON.parse(JSON.stringify("test string"));
 let ty$1 = Js_json.classify(json$1);
 
 if (typeof ty$1 !== "object") {
-  add_test("File \"js_json_test.res\", line 70, characters 16-23", () => ({
+  add_test("File \"js_json_test.res\", line 71, characters 16-23", () => ({
     TAG: "Ok",
     _0: false
   }));
 } else if (ty$1.TAG === "JSONString") {
-  eq("File \"js_json_test.res\", line 69, characters 26-33", ty$1._0, "test string");
+  eq("File \"js_json_test.res\", line 70, characters 26-33", ty$1._0, "test string");
 } else {
-  add_test("File \"js_json_test.res\", line 70, characters 16-23", () => ({
+  add_test("File \"js_json_test.res\", line 71, characters 16-23", () => ({
     TAG: "Ok",
     _0: false
   }));
@@ -173,11 +173,11 @@ let exit = 0;
 if (typeof ty$2 !== "object" || ty$2.TAG !== "JSONNumber") {
   exit = 1;
 } else {
-  eq("File \"js_json_test.res\", line 79, characters 26-33", ty$2._0, 1.23456789);
+  eq("File \"js_json_test.res\", line 80, characters 26-33", ty$2._0, 1.23456789);
 }
 
 if (exit === 1) {
-  add_test("File \"js_json_test.res\", line 80, characters 18-25", () => ({
+  add_test("File \"js_json_test.res\", line 81, characters 18-25", () => ({
     TAG: "Ok",
     _0: false
   }));
@@ -192,11 +192,11 @@ let exit$1 = 0;
 if (typeof ty$3 !== "object" || ty$3.TAG !== "JSONNumber") {
   exit$1 = 1;
 } else {
-  eq("File \"js_json_test.res\", line 89, characters 26-33", ty$3._0 | 0, -1347440721);
+  eq("File \"js_json_test.res\", line 90, characters 26-33", ty$3._0 | 0, -1347440721);
 }
 
 if (exit$1 === 1) {
-  add_test("File \"js_json_test.res\", line 90, characters 18-25", () => ({
+  add_test("File \"js_json_test.res\", line 91, characters 18-25", () => ({
     TAG: "Ok",
     _0: false
   }));
@@ -206,18 +206,18 @@ function test(v) {
   let json = JSON.parse(JSON.stringify(v));
   let ty = Js_json.classify(json);
   if (typeof ty === "object") {
-    return add_test("File \"js_json_test.res\", line 102, characters 18-25", () => ({
+    return add_test("File \"js_json_test.res\", line 103, characters 18-25", () => ({
       TAG: "Ok",
       _0: false
     }));
   }
   switch (ty) {
     case "JSONFalse" :
-      return eq("File \"js_json_test.res\", line 101, characters 24-31", false, v);
+      return eq("File \"js_json_test.res\", line 102, characters 24-31", false, v);
     case "JSONTrue" :
-      return eq("File \"js_json_test.res\", line 100, characters 23-30", true, v);
+      return eq("File \"js_json_test.res\", line 101, characters 23-30", true, v);
     default:
-      return add_test("File \"js_json_test.res\", line 102, characters 18-25", () => ({
+      return add_test("File \"js_json_test.res\", line 103, characters 18-25", () => ({
         TAG: "Ok",
         _0: false
       }));
@@ -236,7 +236,7 @@ function option_get(x) {
     RE_EXN_ID: "Assert_failure",
     _1: [
       "js_json_test.res",
-      113,
+      114,
       12
     ],
     Error: new Error()
@@ -254,7 +254,7 @@ let json$4 = JSON.parse(JSON.stringify(dict));
 let ty$4 = Js_json.classify(json$4);
 
 if (typeof ty$4 !== "object") {
-  add_test("File \"js_json_test.res\", line 144, characters 16-23", () => ({
+  add_test("File \"js_json_test.res\", line 145, characters 16-23", () => ({
     TAG: "Ok",
     _0: false
   }));
@@ -262,45 +262,45 @@ if (typeof ty$4 !== "object") {
   let x = ty$4._0;
   let ta = Js_json.classify(option_get(Js_dict.get(x, "a")));
   if (typeof ta !== "object") {
-    add_test("File \"js_json_test.res\", line 142, characters 18-25", () => ({
+    add_test("File \"js_json_test.res\", line 143, characters 18-25", () => ({
       TAG: "Ok",
       _0: false
     }));
   } else if (ta.TAG === "JSONString") {
     if (ta._0 !== "test string") {
-      add_test("File \"js_json_test.res\", line 133, characters 15-22", () => ({
+      add_test("File \"js_json_test.res\", line 134, characters 15-22", () => ({
         TAG: "Ok",
         _0: false
       }));
     } else {
       let ty$5 = Js_json.classify(option_get(Js_dict.get(x, "b")));
       if (typeof ty$5 !== "object") {
-        add_test("File \"js_json_test.res\", line 139, characters 22-29", () => ({
+        add_test("File \"js_json_test.res\", line 140, characters 22-29", () => ({
           TAG: "Ok",
           _0: false
         }));
       } else if (ty$5.TAG === "JSONNumber") {
         let b = ty$5._0;
-        add_test("File \"js_json_test.res\", line 138, characters 38-45", () => ({
+        add_test("File \"js_json_test.res\", line 139, characters 38-45", () => ({
           TAG: "Approx",
           _0: 123.0,
           _1: b
         }));
       } else {
-        add_test("File \"js_json_test.res\", line 139, characters 22-29", () => ({
+        add_test("File \"js_json_test.res\", line 140, characters 22-29", () => ({
           TAG: "Ok",
           _0: false
         }));
       }
     }
   } else {
-    add_test("File \"js_json_test.res\", line 142, characters 18-25", () => ({
+    add_test("File \"js_json_test.res\", line 143, characters 18-25", () => ({
       TAG: "Ok",
       _0: false
     }));
   }
 } else {
-  add_test("File \"js_json_test.res\", line 144, characters 16-23", () => ({
+  add_test("File \"js_json_test.res\", line 145, characters 16-23", () => ({
     TAG: "Ok",
     _0: false
   }));
@@ -424,11 +424,11 @@ let json$5 = JSON.parse(JSON.stringify(Belt_Array.map([
   "string 2"
 ], prim => prim)));
 
-eq_at_i("File \"js_json_test.res\", line 198, characters 10-17", json$5, 0, "String", "string 0");
+eq_at_i("File \"js_json_test.res\", line 199, characters 10-17", json$5, 0, "String", "string 0");
 
-eq_at_i("File \"js_json_test.res\", line 199, characters 10-17", json$5, 1, "String", "string 1");
+eq_at_i("File \"js_json_test.res\", line 200, characters 10-17", json$5, 1, "String", "string 1");
 
-eq_at_i("File \"js_json_test.res\", line 200, characters 10-17", json$5, 2, "String", "string 2");
+eq_at_i("File \"js_json_test.res\", line 201, characters 10-17", json$5, 2, "String", "string 2");
 
 let json$6 = JSON.parse(JSON.stringify([
   "string 0",
@@ -436,11 +436,11 @@ let json$6 = JSON.parse(JSON.stringify([
   "string 2"
 ]));
 
-eq_at_i("File \"js_json_test.res\", line 207, characters 10-17", json$6, 0, "String", "string 0");
+eq_at_i("File \"js_json_test.res\", line 208, characters 10-17", json$6, 0, "String", "string 0");
 
-eq_at_i("File \"js_json_test.res\", line 208, characters 10-17", json$6, 1, "String", "string 1");
+eq_at_i("File \"js_json_test.res\", line 209, characters 10-17", json$6, 1, "String", "string 1");
 
-eq_at_i("File \"js_json_test.res\", line 209, characters 10-17", json$6, 2, "String", "string 2");
+eq_at_i("File \"js_json_test.res\", line 210, characters 10-17", json$6, 2, "String", "string 2");
 
 let a = [
   1.0000001,
@@ -450,11 +450,11 @@ let a = [
 
 let json$7 = JSON.parse(JSON.stringify(a));
 
-eq_at_i("File \"js_json_test.res\", line 218, characters 10-17", json$7, 0, "Number", Primitive_array.get(a, 0));
+eq_at_i("File \"js_json_test.res\", line 219, characters 10-17", json$7, 0, "Number", Primitive_array.get(a, 0));
 
-eq_at_i("File \"js_json_test.res\", line 219, characters 10-17", json$7, 1, "Number", Primitive_array.get(a, 1));
+eq_at_i("File \"js_json_test.res\", line 220, characters 10-17", json$7, 1, "Number", Primitive_array.get(a, 1));
 
-eq_at_i("File \"js_json_test.res\", line 220, characters 10-17", json$7, 2, "Number", Primitive_array.get(a, 2));
+eq_at_i("File \"js_json_test.res\", line 221, characters 10-17", json$7, 2, "Number", Primitive_array.get(a, 2));
 
 let a$1 = [
   0,
@@ -464,11 +464,11 @@ let a$1 = [
 
 let json$8 = JSON.parse(JSON.stringify(Belt_Array.map(a$1, prim => prim)));
 
-eq_at_i("File \"js_json_test.res\", line 229, characters 10-17", json$8, 0, "Number", Primitive_array.get(a$1, 0));
+eq_at_i("File \"js_json_test.res\", line 230, characters 10-17", json$8, 0, "Number", Primitive_array.get(a$1, 0));
 
-eq_at_i("File \"js_json_test.res\", line 230, characters 10-17", json$8, 1, "Number", Primitive_array.get(a$1, 1));
+eq_at_i("File \"js_json_test.res\", line 231, characters 10-17", json$8, 1, "Number", Primitive_array.get(a$1, 1));
 
-eq_at_i("File \"js_json_test.res\", line 231, characters 10-17", json$8, 2, "Number", Primitive_array.get(a$1, 2));
+eq_at_i("File \"js_json_test.res\", line 232, characters 10-17", json$8, 2, "Number", Primitive_array.get(a$1, 2));
 
 let a$2 = [
   true,
@@ -478,11 +478,11 @@ let a$2 = [
 
 let json$9 = JSON.parse(JSON.stringify(a$2));
 
-eq_at_i("File \"js_json_test.res\", line 240, characters 10-17", json$9, 0, "Boolean", Primitive_array.get(a$2, 0));
+eq_at_i("File \"js_json_test.res\", line 241, characters 10-17", json$9, 0, "Boolean", Primitive_array.get(a$2, 0));
 
-eq_at_i("File \"js_json_test.res\", line 241, characters 10-17", json$9, 1, "Boolean", Primitive_array.get(a$2, 1));
+eq_at_i("File \"js_json_test.res\", line 242, characters 10-17", json$9, 1, "Boolean", Primitive_array.get(a$2, 1));
 
-eq_at_i("File \"js_json_test.res\", line 242, characters 10-17", json$9, 2, "Boolean", Primitive_array.get(a$2, 2));
+eq_at_i("File \"js_json_test.res\", line 243, characters 10-17", json$9, 2, "Boolean", Primitive_array.get(a$2, 2));
 
 function make_d(s, i) {
   let d = {};
@@ -501,40 +501,40 @@ let json$10 = JSON.parse(JSON.stringify(a$3));
 let ty$6 = Js_json.classify(json$10);
 
 if (typeof ty$6 !== "object") {
-  add_test("File \"js_json_test.res\", line 270, characters 16-23", () => ({
+  add_test("File \"js_json_test.res\", line 271, characters 16-23", () => ({
     TAG: "Ok",
     _0: false
   }));
 } else if (ty$6.TAG === "JSONArray") {
   let ty$7 = Js_json.classify(Primitive_array.get(ty$6._0, 1));
   if (typeof ty$7 !== "object") {
-    add_test("File \"js_json_test.res\", line 268, characters 18-25", () => ({
+    add_test("File \"js_json_test.res\", line 269, characters 18-25", () => ({
       TAG: "Ok",
       _0: false
     }));
   } else if (ty$7.TAG === "JSONObject") {
     let ty$8 = Js_json.classify(option_get(Js_dict.get(ty$7._0, "a")));
     if (typeof ty$8 !== "object") {
-      add_test("File \"js_json_test.res\", line 266, characters 20-27", () => ({
+      add_test("File \"js_json_test.res\", line 267, characters 20-27", () => ({
         TAG: "Ok",
         _0: false
       }));
     } else if (ty$8.TAG === "JSONString") {
-      eq("File \"js_json_test.res\", line 265, characters 35-42", ty$8._0, "bbb");
+      eq("File \"js_json_test.res\", line 266, characters 35-42", ty$8._0, "bbb");
     } else {
-      add_test("File \"js_json_test.res\", line 266, characters 20-27", () => ({
+      add_test("File \"js_json_test.res\", line 267, characters 20-27", () => ({
         TAG: "Ok",
         _0: false
       }));
     }
   } else {
-    add_test("File \"js_json_test.res\", line 268, characters 18-25", () => ({
+    add_test("File \"js_json_test.res\", line 269, characters 18-25", () => ({
       TAG: "Ok",
       _0: false
     }));
   }
 } else {
-  add_test("File \"js_json_test.res\", line 270, characters 16-23", () => ({
+  add_test("File \"js_json_test.res\", line 271, characters 16-23", () => ({
     TAG: "Ok",
     _0: false
   }));
@@ -542,24 +542,24 @@ if (typeof ty$6 !== "object") {
 
 try {
   JSON.parse("{{ A}");
-  add_test("File \"js_json_test.res\", line 278, characters 11-18", () => ({
+  add_test("File \"js_json_test.res\", line 279, characters 11-18", () => ({
     TAG: "Ok",
     _0: false
   }));
 } catch (exn) {
-  add_test("File \"js_json_test.res\", line 280, characters 17-24", () => ({
+  add_test("File \"js_json_test.res\", line 281, characters 17-24", () => ({
     TAG: "Ok",
     _0: true
   }));
 }
 
-eq("File \"js_json_test.res\", line 286, characters 12-19", JSON.stringify([
+eq("File \"js_json_test.res\", line 287, characters 12-19", JSON.stringify([
   1,
   2,
   3
 ]), "[1,2,3]");
 
-eq("File \"js_json_test.res\", line 289, characters 2-9", JSON.stringify({
+eq("File \"js_json_test.res\", line 290, characters 2-9", JSON.stringify({
   foo: 1,
   bar: "hello",
   baz: {
@@ -567,88 +567,88 @@ eq("File \"js_json_test.res\", line 289, characters 2-9", JSON.stringify({
   }
 }), "{\"foo\":1,\"bar\":\"hello\",\"baz\":{\"baaz\":10}}");
 
-eq("File \"js_json_test.res\", line 294, characters 12-19", JSON.stringify(null), "null");
+eq("File \"js_json_test.res\", line 295, characters 12-19", JSON.stringify(null), "null");
 
-eq("File \"js_json_test.res\", line 296, characters 12-19", JSON.stringify(undefined), undefined);
+eq("File \"js_json_test.res\", line 297, characters 12-19", JSON.stringify(undefined), undefined);
 
-eq("File \"js_json_test.res\", line 299, characters 5-12", Js_json.decodeString("test"), "test");
+eq("File \"js_json_test.res\", line 300, characters 5-12", Js_json.decodeString("test"), "test");
 
-eq("File \"js_json_test.res\", line 300, characters 5-12", Js_json.decodeString(true), undefined);
+eq("File \"js_json_test.res\", line 301, characters 5-12", Js_json.decodeString(true), undefined);
 
-eq("File \"js_json_test.res\", line 301, characters 5-12", Js_json.decodeString([]), undefined);
+eq("File \"js_json_test.res\", line 302, characters 5-12", Js_json.decodeString([]), undefined);
 
-eq("File \"js_json_test.res\", line 302, characters 5-12", Js_json.decodeString(null), undefined);
+eq("File \"js_json_test.res\", line 303, characters 5-12", Js_json.decodeString(null), undefined);
 
-eq("File \"js_json_test.res\", line 303, characters 5-12", Js_json.decodeString({}), undefined);
+eq("File \"js_json_test.res\", line 304, characters 5-12", Js_json.decodeString({}), undefined);
 
-eq("File \"js_json_test.res\", line 304, characters 5-12", Js_json.decodeString(1.23), undefined);
+eq("File \"js_json_test.res\", line 305, characters 5-12", Js_json.decodeString(1.23), undefined);
 
-eq("File \"js_json_test.res\", line 308, characters 5-12", Js_json.decodeNumber("test"), undefined);
+eq("File \"js_json_test.res\", line 309, characters 5-12", Js_json.decodeNumber("test"), undefined);
 
-eq("File \"js_json_test.res\", line 309, characters 5-12", Js_json.decodeNumber(true), undefined);
+eq("File \"js_json_test.res\", line 310, characters 5-12", Js_json.decodeNumber(true), undefined);
 
-eq("File \"js_json_test.res\", line 310, characters 5-12", Js_json.decodeNumber([]), undefined);
+eq("File \"js_json_test.res\", line 311, characters 5-12", Js_json.decodeNumber([]), undefined);
 
-eq("File \"js_json_test.res\", line 311, characters 5-12", Js_json.decodeNumber(null), undefined);
+eq("File \"js_json_test.res\", line 312, characters 5-12", Js_json.decodeNumber(null), undefined);
 
-eq("File \"js_json_test.res\", line 312, characters 5-12", Js_json.decodeNumber({}), undefined);
+eq("File \"js_json_test.res\", line 313, characters 5-12", Js_json.decodeNumber({}), undefined);
 
-eq("File \"js_json_test.res\", line 313, characters 5-12", Js_json.decodeNumber(1.23), 1.23);
+eq("File \"js_json_test.res\", line 314, characters 5-12", Js_json.decodeNumber(1.23), 1.23);
 
-eq("File \"js_json_test.res\", line 317, characters 5-12", Js_json.decodeObject("test"), undefined);
+eq("File \"js_json_test.res\", line 318, characters 5-12", Js_json.decodeObject("test"), undefined);
 
-eq("File \"js_json_test.res\", line 318, characters 5-12", Js_json.decodeObject(true), undefined);
+eq("File \"js_json_test.res\", line 319, characters 5-12", Js_json.decodeObject(true), undefined);
 
-eq("File \"js_json_test.res\", line 319, characters 5-12", Js_json.decodeObject([]), undefined);
+eq("File \"js_json_test.res\", line 320, characters 5-12", Js_json.decodeObject([]), undefined);
 
-eq("File \"js_json_test.res\", line 320, characters 5-12", Js_json.decodeObject(null), undefined);
+eq("File \"js_json_test.res\", line 321, characters 5-12", Js_json.decodeObject(null), undefined);
 
-eq("File \"js_json_test.res\", line 321, characters 5-12", Js_json.decodeObject({}), {});
+eq("File \"js_json_test.res\", line 322, characters 5-12", Js_json.decodeObject({}), {});
 
-eq("File \"js_json_test.res\", line 322, characters 5-12", Js_json.decodeObject(1.23), undefined);
+eq("File \"js_json_test.res\", line 323, characters 5-12", Js_json.decodeObject(1.23), undefined);
 
-eq("File \"js_json_test.res\", line 326, characters 5-12", Js_json.decodeArray("test"), undefined);
+eq("File \"js_json_test.res\", line 327, characters 5-12", Js_json.decodeArray("test"), undefined);
 
-eq("File \"js_json_test.res\", line 327, characters 5-12", Js_json.decodeArray(true), undefined);
+eq("File \"js_json_test.res\", line 328, characters 5-12", Js_json.decodeArray(true), undefined);
 
-eq("File \"js_json_test.res\", line 328, characters 5-12", Js_json.decodeArray([]), []);
+eq("File \"js_json_test.res\", line 329, characters 5-12", Js_json.decodeArray([]), []);
 
-eq("File \"js_json_test.res\", line 329, characters 5-12", Js_json.decodeArray(null), undefined);
+eq("File \"js_json_test.res\", line 330, characters 5-12", Js_json.decodeArray(null), undefined);
 
-eq("File \"js_json_test.res\", line 330, characters 5-12", Js_json.decodeArray({}), undefined);
+eq("File \"js_json_test.res\", line 331, characters 5-12", Js_json.decodeArray({}), undefined);
 
-eq("File \"js_json_test.res\", line 331, characters 5-12", Js_json.decodeArray(1.23), undefined);
+eq("File \"js_json_test.res\", line 332, characters 5-12", Js_json.decodeArray(1.23), undefined);
 
-eq("File \"js_json_test.res\", line 335, characters 5-12", Js_json.decodeBoolean("test"), undefined);
+eq("File \"js_json_test.res\", line 336, characters 5-12", Js_json.decodeBoolean("test"), undefined);
 
-eq("File \"js_json_test.res\", line 336, characters 5-12", Js_json.decodeBoolean(true), true);
+eq("File \"js_json_test.res\", line 337, characters 5-12", Js_json.decodeBoolean(true), true);
 
-eq("File \"js_json_test.res\", line 337, characters 5-12", Js_json.decodeBoolean([]), undefined);
+eq("File \"js_json_test.res\", line 338, characters 5-12", Js_json.decodeBoolean([]), undefined);
 
-eq("File \"js_json_test.res\", line 338, characters 5-12", Js_json.decodeBoolean(null), undefined);
+eq("File \"js_json_test.res\", line 339, characters 5-12", Js_json.decodeBoolean(null), undefined);
 
-eq("File \"js_json_test.res\", line 339, characters 5-12", Js_json.decodeBoolean({}), undefined);
+eq("File \"js_json_test.res\", line 340, characters 5-12", Js_json.decodeBoolean({}), undefined);
 
-eq("File \"js_json_test.res\", line 340, characters 5-12", Js_json.decodeBoolean(1.23), undefined);
+eq("File \"js_json_test.res\", line 341, characters 5-12", Js_json.decodeBoolean(1.23), undefined);
 
-eq("File \"js_json_test.res\", line 344, characters 5-12", Js_json.decodeNull("test"), undefined);
+eq("File \"js_json_test.res\", line 345, characters 5-12", Js_json.decodeNull("test"), undefined);
 
-eq("File \"js_json_test.res\", line 345, characters 5-12", Js_json.decodeNull(true), undefined);
+eq("File \"js_json_test.res\", line 346, characters 5-12", Js_json.decodeNull(true), undefined);
 
-eq("File \"js_json_test.res\", line 346, characters 5-12", Js_json.decodeNull([]), undefined);
+eq("File \"js_json_test.res\", line 347, characters 5-12", Js_json.decodeNull([]), undefined);
 
-eq("File \"js_json_test.res\", line 347, characters 5-12", Js_json.decodeNull(null), null);
+eq("File \"js_json_test.res\", line 348, characters 5-12", Js_json.decodeNull(null), null);
 
-eq("File \"js_json_test.res\", line 348, characters 5-12", Js_json.decodeNull({}), undefined);
+eq("File \"js_json_test.res\", line 349, characters 5-12", Js_json.decodeNull({}), undefined);
 
-eq("File \"js_json_test.res\", line 349, characters 5-12", Js_json.decodeNull(1.23), undefined);
+eq("File \"js_json_test.res\", line 350, characters 5-12", Js_json.decodeNull(1.23), undefined);
 
 function id(obj) {
   return Js_json.deserializeUnsafe(Js_json.serializeExn(obj));
 }
 
 function idtest(obj) {
-  eq("File \"js_json_test.res\", line 354, characters 23-30", obj, Js_json.deserializeUnsafe(Js_json.serializeExn(obj)));
+  eq("File \"js_json_test.res\", line 355, characters 23-30", obj, Js_json.deserializeUnsafe(Js_json.serializeExn(obj)));
 }
 
 idtest(undefined);
@@ -682,8 +682,11 @@ Mt.from_pair_suites("Js_json_test", suites.contents);
 
 let J;
 
+let $$Array;
+
 exports.suites = suites;
 exports.J = J;
+exports.$$Array = $$Array;
 exports.add_test = add_test;
 exports.eq = eq;
 exports.false_ = false_;
diff --git a/tests/tests/src/js_json_test.res b/tests/tests/src/js_json_test.res
index 58e03d5e80..15558f9aeb 100644
--- a/tests/tests/src/js_json_test.res
+++ b/tests/tests/src/js_json_test.res
@@ -1,5 +1,6 @@
 let suites: ref<Mt.pair_suites> = ref(list{})
 module J = Js.Json
+module Array = Ocaml_Array
 
 let add_test = {
   let counter = ref(0)
diff --git a/tests/tests/src/js_re_test.js b/tests/tests/src/js_re_test.js
index 1d84b0fc9e..c202252c06 100644
--- a/tests/tests/src/js_re_test.js
+++ b/tests/tests/src/js_re_test.js
@@ -272,5 +272,8 @@ let suites = {
 
 Mt.from_pair_suites("Js_re_test", suites);
 
+let $$Array;
+
+exports.$$Array = $$Array;
 exports.suites = suites;
 /*  Not a pure module */
diff --git a/tests/tests/src/js_re_test.res b/tests/tests/src/js_re_test.res
index 21a0e6b550..925cf2c385 100644
--- a/tests/tests/src/js_re_test.res
+++ b/tests/tests/src/js_re_test.res
@@ -1,3 +1,5 @@
+module Array = Ocaml_Array
+
 let suites = {
   open Mt
   list{
diff --git a/tests/tests/src/module_missing_conversion.js b/tests/tests/src/module_missing_conversion.js
index a581664ab4..79576d6618 100644
--- a/tests/tests/src/module_missing_conversion.js
+++ b/tests/tests/src/module_missing_conversion.js
@@ -88,7 +88,10 @@ let u = [$$String];
 
 let hh = "x".length;
 
+let $$Array;
+
+exports.$$Array = $$Array;
 exports.XX = XX;
 exports.u = u;
 exports.hh = hh;
-/* No side effect */
+/* hh Not a pure module */
diff --git a/tests/tests/src/module_missing_conversion.res b/tests/tests/src/module_missing_conversion.res
index 840637ee29..1265746701 100644
--- a/tests/tests/src/module_missing_conversion.res
+++ b/tests/tests/src/module_missing_conversion.res
@@ -1,3 +1,5 @@
+module Array = Ocaml_Array
+
 module type S = module type of String
 
 module XX = {
diff --git a/tests/tests/src/module_parameter_test.js b/tests/tests/src/module_parameter_test.js
index 029ab2d8d6..d34dbf1226 100644
--- a/tests/tests/src/module_parameter_test.js
+++ b/tests/tests/src/module_parameter_test.js
@@ -53,4 +53,4 @@ exports.N = N;
 exports.v0 = v0;
 exports.v = v;
 exports.suites = suites;
-/*  Not a pure module */
+/* v0 Not a pure module */
diff --git a/tests/tests/src/ocaml_compat/Ocaml_Array.js b/tests/tests/src/ocaml_compat/Ocaml_Array.js
new file mode 100644
index 0000000000..15cf696cd9
--- /dev/null
+++ b/tests/tests/src/ocaml_compat/Ocaml_Array.js
@@ -0,0 +1,480 @@
+// Generated by ReScript, PLEASE EDIT WITH CARE
+'use strict';
+
+let Ocaml_List = require("./Ocaml_List.js");
+let Pervasives = require("rescript/lib/js/Pervasives.js");
+let Primitive_array = require("rescript/lib/js/Primitive_array.js");
+let Primitive_exceptions = require("rescript/lib/js/Primitive_exceptions.js");
+
+let init = ((length, f) => Array.from({ length }, f));
+
+function make(len, x) {
+  return init(len, param => x);
+}
+
+function unsafe_sub(array, offset, length) {
+  return array.slice(offset, offset + length | 0);
+}
+
+function concat(list) {
+  return Ocaml_List.fold_left((arr1, arr2) => arr1.concat(arr2), [], list);
+}
+
+function create_float(len) {
+  return init(len, param => 0.0);
+}
+
+function make_matrix(sx, sy, init$1) {
+  let x = [];
+  let res = init(sx, param => x);
+  for (let x$1 = 0; x$1 < sx; ++x$1) {
+    res[x$1] = init(sy, param => init$1);
+  }
+  return res;
+}
+
+function append(a1, a2) {
+  let l1 = a1.length;
+  if (l1 === 0) {
+    return a2.slice();
+  } else if (a2.length === 0) {
+    return unsafe_sub(a1, 0, l1);
+  } else {
+    return a1.concat(a2);
+  }
+}
+
+function sub(a, ofs, len) {
+  if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
+    return Pervasives.invalid_arg("Array.sub");
+  } else {
+    return unsafe_sub(a, ofs, len);
+  }
+}
+
+function fill(a, ofs, len, v) {
+  if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
+    return Pervasives.invalid_arg("Array.fill");
+  }
+  for (let i = ofs, i_finish = ofs + len | 0; i < i_finish; ++i) {
+    a[i] = v;
+  }
+}
+
+function blit(a1, ofs1, a2, ofs2, len) {
+  if (len < 0 || ofs1 < 0 || ofs1 > (a1.length - len | 0) || ofs2 < 0 || ofs2 > (a2.length - len | 0)) {
+    return Pervasives.invalid_arg("Array.blit");
+  } else {
+    for (let i = 0; i < len; ++i) {
+      a2[ofs2 + i | 0] = a1[ofs1 + i | 0];
+    }
+    return;
+  }
+}
+
+function iter(f, a) {
+  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
+    f(a[i]);
+  }
+}
+
+function iter2(f, a, b) {
+  if (a.length !== b.length) {
+    return Pervasives.invalid_arg("Array.iter2: arrays must have the same length");
+  }
+  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
+    f(a[i], b[i]);
+  }
+}
+
+function map(f, a) {
+  let l = a.length;
+  if (l === 0) {
+    return [];
+  }
+  let x = f(a[0]);
+  let r = init(l, param => x);
+  for (let i = 1; i < l; ++i) {
+    r[i] = f(a[i]);
+  }
+  return r;
+}
+
+function map2(f, a, b) {
+  let la = a.length;
+  let lb = b.length;
+  if (la !== lb) {
+    return Pervasives.invalid_arg("Array.map2: arrays must have the same length");
+  }
+  if (la === 0) {
+    return [];
+  }
+  let x = f(a[0], b[0]);
+  let r = init(la, param => x);
+  for (let i = 1; i < la; ++i) {
+    r[i] = f(a[i], b[i]);
+  }
+  return r;
+}
+
+function iteri(f, a) {
+  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
+    f(i, a[i]);
+  }
+}
+
+function mapi(f, a) {
+  let l = a.length;
+  if (l === 0) {
+    return [];
+  }
+  let x = f(0, a[0]);
+  let r = init(l, param => x);
+  for (let i = 1; i < l; ++i) {
+    r[i] = f(i, a[i]);
+  }
+  return r;
+}
+
+function to_list(a) {
+  let _i = a.length - 1 | 0;
+  let _res = /* [] */0;
+  while (true) {
+    let res = _res;
+    let i = _i;
+    if (i < 0) {
+      return res;
+    }
+    _res = {
+      hd: a[i],
+      tl: res
+    };
+    _i = i - 1 | 0;
+    continue;
+  };
+}
+
+function list_length(_accu, _param) {
+  while (true) {
+    let param = _param;
+    let accu = _accu;
+    if (!param) {
+      return accu;
+    }
+    _param = param.tl;
+    _accu = accu + 1 | 0;
+    continue;
+  };
+}
+
+function of_list(param) {
+  if (!param) {
+    return [];
+  }
+  let hd = param.hd;
+  let len = list_length(0, param);
+  let a = init(len, param => hd);
+  let _i = 1;
+  let _param = param.tl;
+  while (true) {
+    let param$1 = _param;
+    let i = _i;
+    if (!param$1) {
+      return a;
+    }
+    a[i] = param$1.hd;
+    _param = param$1.tl;
+    _i = i + 1 | 0;
+    continue;
+  };
+}
+
+function fold_left(f, x, a) {
+  let r = x;
+  for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
+    r = f(r, a[i]);
+  }
+  return r;
+}
+
+function fold_right(f, a, x) {
+  let r = x;
+  for (let i = a.length - 1 | 0; i >= 0; --i) {
+    r = f(a[i], r);
+  }
+  return r;
+}
+
+function exists(p, a) {
+  let n = a.length;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    if (i === n) {
+      return false;
+    }
+    if (p(a[i])) {
+      return true;
+    }
+    _i = i + 1 | 0;
+    continue;
+  };
+}
+
+function for_all(p, a) {
+  let n = a.length;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    if (i === n) {
+      return true;
+    }
+    if (!p(a[i])) {
+      return false;
+    }
+    _i = i + 1 | 0;
+    continue;
+  };
+}
+
+function mem(x, a) {
+  let n = a.length;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    if (i === n) {
+      return false;
+    }
+    if (a[i] === x) {
+      return true;
+    }
+    _i = i + 1 | 0;
+    continue;
+  };
+}
+
+function memq(x, a) {
+  let n = a.length;
+  let _i = 0;
+  while (true) {
+    let i = _i;
+    if (i === n) {
+      return false;
+    }
+    if (x === a[i]) {
+      return true;
+    }
+    _i = i + 1 | 0;
+    continue;
+  };
+}
+
+let Bottom = /* @__PURE__ */Primitive_exceptions.create("Ocaml_Array.Bottom");
+
+function sort(cmp, a) {
+  let maxson = (l, i) => {
+    let i31 = ((i + i | 0) + i | 0) + 1 | 0;
+    let x = i31;
+    if ((i31 + 2 | 0) < l) {
+      if (cmp(Primitive_array.get(a, i31), Primitive_array.get(a, i31 + 1 | 0)) < 0) {
+        x = i31 + 1 | 0;
+      }
+      if (cmp(Primitive_array.get(a, x), Primitive_array.get(a, i31 + 2 | 0)) < 0) {
+        x = i31 + 2 | 0;
+      }
+      return x;
+    }
+    if ((i31 + 1 | 0) < l && cmp(Primitive_array.get(a, i31), Primitive_array.get(a, i31 + 1 | 0)) < 0) {
+      return i31 + 1 | 0;
+    }
+    if (i31 < l) {
+      return i31;
+    }
+    throw {
+      RE_EXN_ID: Bottom,
+      _1: i,
+      Error: new Error()
+    };
+  };
+  let trickle = (l, i, e) => {
+    try {
+      let _i = i;
+      while (true) {
+        let i$1 = _i;
+        let j = maxson(l, i$1);
+        if (cmp(Primitive_array.get(a, j), e) <= 0) {
+          return Primitive_array.set(a, i$1, e);
+        }
+        Primitive_array.set(a, i$1, Primitive_array.get(a, j));
+        _i = j;
+        continue;
+      };
+    } catch (raw_i) {
+      let i$2 = Primitive_exceptions.internalToException(raw_i);
+      if (i$2.RE_EXN_ID === Bottom) {
+        return Primitive_array.set(a, i$2._1, e);
+      }
+      throw i$2;
+    }
+  };
+  let bubble = (l, i) => {
+    try {
+      let _i = i;
+      while (true) {
+        let i$1 = _i;
+        let j = maxson(l, i$1);
+        Primitive_array.set(a, i$1, Primitive_array.get(a, j));
+        _i = j;
+        continue;
+      };
+    } catch (raw_i) {
+      let i$2 = Primitive_exceptions.internalToException(raw_i);
+      if (i$2.RE_EXN_ID === Bottom) {
+        return i$2._1;
+      }
+      throw i$2;
+    }
+  };
+  let trickleup = (_i, e) => {
+    while (true) {
+      let i = _i;
+      let father = (i - 1 | 0) / 3 | 0;
+      if (i === father) {
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "Ocaml_Array.res",
+            296,
+            4
+          ],
+          Error: new Error()
+        };
+      }
+      if (cmp(Primitive_array.get(a, father), e) >= 0) {
+        return Primitive_array.set(a, i, e);
+      }
+      Primitive_array.set(a, i, Primitive_array.get(a, father));
+      if (father <= 0) {
+        return Primitive_array.set(a, 0, e);
+      }
+      _i = father;
+      continue;
+    };
+  };
+  let l = a.length;
+  for (let i = ((l + 1 | 0) / 3 | 0) - 1 | 0; i >= 0; --i) {
+    trickle(l, i, Primitive_array.get(a, i));
+  }
+  for (let i$1 = l - 1 | 0; i$1 >= 2; --i$1) {
+    let e = Primitive_array.get(a, i$1);
+    Primitive_array.set(a, i$1, Primitive_array.get(a, 0));
+    trickleup(bubble(i$1, 0), e);
+  }
+  if (l <= 1) {
+    return;
+  }
+  let e$1 = Primitive_array.get(a, 1);
+  Primitive_array.set(a, 1, Primitive_array.get(a, 0));
+  Primitive_array.set(a, 0, e$1);
+}
+
+function stable_sort(cmp, a) {
+  let merge = (src1ofs, src1len, src2, src2ofs, src2len, dst, dstofs) => {
+    let src1r = src1ofs + src1len | 0;
+    let src2r = src2ofs + src2len | 0;
+    let _i1 = src1ofs;
+    let _s1 = Primitive_array.get(a, src1ofs);
+    let _i2 = src2ofs;
+    let _s2 = Primitive_array.get(src2, src2ofs);
+    let _d = dstofs;
+    while (true) {
+      let d = _d;
+      let s2 = _s2;
+      let i2 = _i2;
+      let s1 = _s1;
+      let i1 = _i1;
+      if (cmp(s1, s2) <= 0) {
+        Primitive_array.set(dst, d, s1);
+        let i1$1 = i1 + 1 | 0;
+        if (i1$1 >= src1r) {
+          return blit(src2, i2, dst, d + 1 | 0, src2r - i2 | 0);
+        }
+        _d = d + 1 | 0;
+        _s1 = Primitive_array.get(a, i1$1);
+        _i1 = i1$1;
+        continue;
+      }
+      Primitive_array.set(dst, d, s2);
+      let i2$1 = i2 + 1 | 0;
+      if (i2$1 >= src2r) {
+        return blit(a, i1, dst, d + 1 | 0, src1r - i1 | 0);
+      }
+      _d = d + 1 | 0;
+      _s2 = Primitive_array.get(src2, i2$1);
+      _i2 = i2$1;
+      continue;
+    };
+  };
+  let isortto = (srcofs, dst, dstofs, len) => {
+    for (let i = 0; i < len; ++i) {
+      let e = Primitive_array.get(a, srcofs + i | 0);
+      let j = (dstofs + i | 0) - 1 | 0;
+      while (j >= dstofs && cmp(Primitive_array.get(dst, j), e) > 0) {
+        Primitive_array.set(dst, j + 1 | 0, Primitive_array.get(dst, j));
+        j = j - 1 | 0;
+      };
+      Primitive_array.set(dst, j + 1 | 0, e);
+    }
+  };
+  let sortto = (srcofs, dst, dstofs, len) => {
+    if (len <= 5) {
+      return isortto(srcofs, dst, dstofs, len);
+    }
+    let l1 = len / 2 | 0;
+    let l2 = len - l1 | 0;
+    sortto(srcofs + l1 | 0, dst, dstofs + l1 | 0, l2);
+    sortto(srcofs, a, srcofs + l2 | 0, l1);
+    merge(srcofs + l2 | 0, l1, dst, dstofs + l1 | 0, l2, dst, dstofs);
+  };
+  let l = a.length;
+  if (l <= 5) {
+    return isortto(0, a, 0, l);
+  }
+  let l1 = l / 2 | 0;
+  let l2 = l - l1 | 0;
+  let x = Primitive_array.get(a, 0);
+  let t = init(l2, param => x);
+  sortto(l1, t, 0, l2);
+  sortto(0, a, l2, l1);
+  merge(l2, l1, t, 0, l2, a, 0);
+}
+
+let fast_sort = stable_sort;
+
+exports.make = make;
+exports.create_float = create_float;
+exports.init = init;
+exports.make_matrix = make_matrix;
+exports.append = append;
+exports.concat = concat;
+exports.sub = sub;
+exports.fill = fill;
+exports.blit = blit;
+exports.to_list = to_list;
+exports.of_list = of_list;
+exports.iter = iter;
+exports.iteri = iteri;
+exports.map = map;
+exports.mapi = mapi;
+exports.fold_left = fold_left;
+exports.fold_right = fold_right;
+exports.iter2 = iter2;
+exports.map2 = map2;
+exports.for_all = for_all;
+exports.exists = exists;
+exports.mem = mem;
+exports.memq = memq;
+exports.sort = sort;
+exports.stable_sort = stable_sort;
+exports.fast_sort = fast_sort;
+/* No side effect */
diff --git a/tests/tests/src/ocaml_compat/Ocaml_Array.res b/tests/tests/src/ocaml_compat/Ocaml_Array.res
new file mode 100644
index 0000000000..a72920bd5f
--- /dev/null
+++ b/tests/tests/src/ocaml_compat/Ocaml_Array.res
@@ -0,0 +1,385 @@
+// FIXME:
+//   This exists for compatibility reason.
+//   Move this into Pervasives or Core
+
+module List = Ocaml_List
+
+// Caution: `Array.get` is implicitly used by `array[idx]` syntax
+external get: (array<'a>, int) => 'a = "%array_safe_get"
+
+// Caution: `Array.set` is implicitly used by `array[idx]` syntax
+external set: (array<'a>, int, 'a) => unit = "%array_safe_set"
+
+// Below is all deprecated and should be removed in v13
+
+external length: array<'a> => int = "%array_length"
+
+external unsafe_get: (array<'a>, int) => 'a = "%array_unsafe_get"
+
+external unsafe_set: (array<'a>, int, 'a) => unit = "%array_unsafe_set"
+
+let init: (int, int => 'a) => array<'a> = %raw(`(length, f) => Array.from({ length }, f)`)
+
+let make = (len, x) => init(len, _ => x)
+
+@send external slice: (array<'a>, int, int) => array<'a> = "slice"
+let unsafe_sub = (array, offset, length) => array->slice(offset, offset + length)
+
+@send external concat: (array<'a>, array<'a>) => array<'a> = "concat"
+@send external append_prim: (array<'a>, array<'a>) => array<'a> = "concat"
+
+let concat = list => {
+  List.fold_left((arr1, arr2) => arr1->concat(arr2), [], list)
+}
+
+let unsafe_blit = (srcArray, srcOffset, destArray, destOffset, len) => {
+  for i in 0 to len - 1 {
+    destArray->unsafe_set(destOffset + i, srcArray->unsafe_get(srcOffset + i))
+  }
+}
+
+let create_float = len => make(len, 0.0)
+
+let make_matrix = (sx, sy, init) => {
+  let res = make(sx, [])
+  for x in 0 to pred(sx) {
+    unsafe_set(res, x, make(sy, init))
+  }
+  res
+}
+
+@send external copy: array<'a> => array<'a> = "slice"
+
+let append = (a1, a2) => {
+  let l1 = length(a1)
+  if l1 == 0 {
+    copy(a2)
+  } else if length(a2) == 0 {
+    unsafe_sub(a1, 0, l1)
+  } else {
+    append_prim(a1, a2)
+  }
+}
+
+let sub = (a, ofs, len) =>
+  if ofs < 0 || (len < 0 || ofs > length(a) - len) {
+    invalid_arg("Array.sub")
+  } else {
+    unsafe_sub(a, ofs, len)
+  }
+
+let fill = (a, ofs, len, v) =>
+  if ofs < 0 || (len < 0 || ofs > length(a) - len) {
+    invalid_arg("Array.fill")
+  } else {
+    for i in ofs to ofs + len - 1 {
+      unsafe_set(a, i, v)
+    }
+  }
+
+let blit = (a1, ofs1, a2, ofs2, len) =>
+  if len < 0 || (ofs1 < 0 || (ofs1 > length(a1) - len || (ofs2 < 0 || ofs2 > length(a2) - len))) {
+    invalid_arg("Array.blit")
+  } else {
+    unsafe_blit(a1, ofs1, a2, ofs2, len)
+  }
+
+let iter = (f, a) =>
+  for i in 0 to length(a) - 1 {
+    f(unsafe_get(a, i))
+  }
+
+let iter2 = (f, a, b) =>
+  if length(a) != length(b) {
+    invalid_arg("Array.iter2: arrays must have the same length")
+  } else {
+    for i in 0 to length(a) - 1 {
+      f(unsafe_get(a, i), unsafe_get(b, i))
+    }
+  }
+
+let map = (f, a) => {
+  let l = length(a)
+  if l == 0 {
+    []
+  } else {
+    let r = make(l, f(unsafe_get(a, 0)))
+    for i in 1 to l - 1 {
+      unsafe_set(r, i, f(unsafe_get(a, i)))
+    }
+    r
+  }
+}
+
+let map2 = (f, a, b) => {
+  let la = length(a)
+  let lb = length(b)
+  if la != lb {
+    invalid_arg("Array.map2: arrays must have the same length")
+  } else if la == 0 {
+    []
+  } else {
+    let r = make(la, f(unsafe_get(a, 0), unsafe_get(b, 0)))
+    for i in 1 to la - 1 {
+      unsafe_set(r, i, f(unsafe_get(a, i), unsafe_get(b, i)))
+    }
+    r
+  }
+}
+
+let iteri = (f, a) =>
+  for i in 0 to length(a) - 1 {
+    f(i, unsafe_get(a, i))
+  }
+
+let mapi = (f, a) => {
+  let l = length(a)
+  if l == 0 {
+    []
+  } else {
+    let r = make(l, f(0, unsafe_get(a, 0)))
+    for i in 1 to l - 1 {
+      unsafe_set(r, i, f(i, unsafe_get(a, i)))
+    }
+    r
+  }
+}
+
+let to_list = a => {
+  let rec tolist = (i, res) =>
+    if i < 0 {
+      res
+    } else {
+      tolist(i - 1, list{unsafe_get(a, i), ...res})
+    }
+  tolist(length(a) - 1, list{})
+}
+
+/* Cannot use List.length here because the List module depends on Array. */
+let rec list_length = (accu, param) =>
+  switch param {
+  | list{} => accu
+  | list{_, ...t} => list_length(succ(accu), t)
+  }
+
+let of_list = param =>
+  switch param {
+  | list{} => []
+  | list{hd, ...tl} as l =>
+    let a = make(list_length(0, l), hd)
+    let rec fill = (i, param) =>
+      switch param {
+      | list{} => a
+      | list{hd, ...tl} =>
+        unsafe_set(a, i, hd)
+        fill(i + 1, tl)
+      }
+    fill(1, tl)
+  }
+
+let fold_left = (f, x, a) => {
+  let r = ref(x)
+  for i in 0 to length(a) - 1 {
+    r := f(r.contents, unsafe_get(a, i))
+  }
+  r.contents
+}
+
+let fold_right = (f, a, x) => {
+  let r = ref(x)
+  for i in length(a) - 1 downto 0 {
+    r := f(unsafe_get(a, i), r.contents)
+  }
+  r.contents
+}
+
+let exists = (p, a) => {
+  let n = length(a)
+  let rec loop = i =>
+    if i == n {
+      false
+    } else if p(unsafe_get(a, i)) {
+      true
+    } else {
+      loop(succ(i))
+    }
+  loop(0)
+}
+
+let for_all = (p, a) => {
+  let n = length(a)
+  let rec loop = i =>
+    if i == n {
+      true
+    } else if p(unsafe_get(a, i)) {
+      loop(succ(i))
+    } else {
+      false
+    }
+  loop(0)
+}
+
+let mem = (x, a) => {
+  let n = length(a)
+  let rec loop = i =>
+    if i == n {
+      false
+    } else if compare(unsafe_get(a, i), x) == 0 {
+      true
+    } else {
+      loop(succ(i))
+    }
+  loop(0)
+}
+
+let memq = (x, a) => {
+  let n = length(a)
+  let rec loop = i =>
+    if i == n {
+      false
+    } else if x === unsafe_get(a, i) {
+      true
+    } else {
+      loop(succ(i))
+    }
+  loop(0)
+}
+
+exception Bottom(int)
+let sort = (cmp, a) => {
+  let maxson = (l, i) => {
+    let i31 = i + i + i + 1
+    let x = ref(i31)
+    if i31 + 2 < l {
+      if cmp(get(a, i31), get(a, i31 + 1)) < 0 {
+        x := i31 + 1
+      }
+      if cmp(get(a, x.contents), get(a, i31 + 2)) < 0 {
+        x := i31 + 2
+      }
+      x.contents
+    } else if i31 + 1 < l && cmp(get(a, i31), get(a, i31 + 1)) < 0 {
+      i31 + 1
+    } else if i31 < l {
+      i31
+    } else {
+      raise(Bottom(i))
+    }
+  }
+
+  let rec trickledown = (l, i, e) => {
+    let j = maxson(l, i)
+    if cmp(get(a, j), e) > 0 {
+      set(a, i, get(a, j))
+      trickledown(l, j, e)
+    } else {
+      set(a, i, e)
+    }
+  }
+
+  let trickle = (l, i, e) =>
+    try trickledown(l, i, e) catch {
+    | Bottom(i) => set(a, i, e)
+    }
+  let rec bubbledown = (l, i) => {
+    let j = maxson(l, i)
+    set(a, i, get(a, j))
+    bubbledown(l, j)
+  }
+
+  let bubble = (l, i) =>
+    try bubbledown(l, i) catch {
+    | Bottom(i) => i
+    }
+  let rec trickleup = (i, e) => {
+    let father = (i - 1) / 3
+    assert(i != father)
+    if cmp(get(a, father), e) < 0 {
+      set(a, i, get(a, father))
+      if father > 0 {
+        trickleup(father, e)
+      } else {
+        set(a, 0, e)
+      }
+    } else {
+      set(a, i, e)
+    }
+  }
+
+  let l = length(a)
+  for i in (l + 1) / 3 - 1 downto 0 {
+    trickle(l, i, get(a, i))
+  }
+  for i in l - 1 downto 2 {
+    let e = get(a, i)
+    set(a, i, get(a, 0))
+    trickleup(bubble(i, 0), e)
+  }
+  if l > 1 {
+    let e = get(a, 1)
+    set(a, 1, get(a, 0))
+    set(a, 0, e)
+  }
+}
+
+let cutoff = 5
+let stable_sort = (cmp, a) => {
+  let merge = (src1ofs, src1len, src2, src2ofs, src2len, dst, dstofs) => {
+    let src1r = src1ofs + src1len and src2r = src2ofs + src2len
+    let rec loop = (i1, s1, i2, s2, d) =>
+      if cmp(s1, s2) <= 0 {
+        set(dst, d, s1)
+        let i1 = i1 + 1
+        if i1 < src1r {
+          loop(i1, get(a, i1), i2, s2, d + 1)
+        } else {
+          blit(src2, i2, dst, d + 1, src2r - i2)
+        }
+      } else {
+        set(dst, d, s2)
+        let i2 = i2 + 1
+        if i2 < src2r {
+          loop(i1, s1, i2, get(src2, i2), d + 1)
+        } else {
+          blit(a, i1, dst, d + 1, src1r - i1)
+        }
+      }
+    loop(src1ofs, get(a, src1ofs), src2ofs, get(src2, src2ofs), dstofs)
+  }
+
+  let isortto = (srcofs, dst, dstofs, len) =>
+    for i in 0 to len - 1 {
+      let e = get(a, srcofs + i)
+      let j = ref(dstofs + i - 1)
+      while j.contents >= dstofs && cmp(get(dst, j.contents), e) > 0 {
+        set(dst, j.contents + 1, get(dst, j.contents))
+        decr(j)
+      }
+      set(dst, j.contents + 1, e)
+    }
+
+  let rec sortto = (srcofs, dst, dstofs, len) =>
+    if len <= cutoff {
+      isortto(srcofs, dst, dstofs, len)
+    } else {
+      let l1 = len / 2
+      let l2 = len - l1
+      sortto(srcofs + l1, dst, dstofs + l1, l2)
+      sortto(srcofs, a, srcofs + l2, l1)
+      merge(srcofs + l2, l1, dst, dstofs + l1, l2, dst, dstofs)
+    }
+
+  let l = length(a)
+  if l <= cutoff {
+    isortto(0, a, 0, l)
+  } else {
+    let l1 = l / 2
+    let l2 = l - l1
+    let t = make(l2, get(a, 0))
+    sortto(l1, t, 0, l2)
+    sortto(0, a, l2, l1)
+    merge(l2, l1, t, 0, l2, a, 0)
+  }
+}
+
+let fast_sort = stable_sort
diff --git a/tests/tests/src/ocaml_compat/Ocaml_Array.resi b/tests/tests/src/ocaml_compat/Ocaml_Array.resi
new file mode 100644
index 0000000000..74a7c24724
--- /dev/null
+++ b/tests/tests/src/ocaml_compat/Ocaml_Array.resi
@@ -0,0 +1,249 @@
+// FIXME:
+//   This exists for compatibility reason.
+//   Move this into Pervasives or Core
+
+// Caution: `Array.get` is implicitly used by `array[idx]` syntax
+external get: (array<'a>, int) => 'a = "%array_safe_get"
+
+// Caution: `Array.set` is implicitly used by `array[idx]` syntax
+external set: (array<'a>, int, 'a) => unit = "%array_safe_set"
+
+// Below is all deprecated and should be removed in v13
+
+/** Return the length (number of elements) of the given array. */
+@deprecated("Use Core instead. This will be removed in v13")
+external length: array<'a> => int = "%array_length"
+
+/** [Array.make n x] returns a fresh array of length [n],
+   initialized with [x].
+   All the elements of this new array are initially
+   physically equal to [x] (in the sense of the [==] predicate).
+   Consequently, if [x] is mutable, it is shared among all elements
+   of the array, and modifying [x] through one of the array entries
+   will modify all other entries at the same time.
+
+   Raise [Invalid_argument] if [n < 0] or [n > Sys.max_array_length].
+   If the value of [x] is a floating-point number, then the maximum
+   size is only [Sys.max_array_length / 2].*/
+@deprecated("Use Core instead. This will be removed in v13")
+let make: (int, 'a) => array<'a>
+
+/** [Array.create_float n] returns a fresh float array of length [n],
+    with uninitialized data.
+    @since 4.03 */
+@deprecated("Use Core instead. This will be removed in v13")
+let create_float: int => array<float>
+
+/** [Array.init n f] returns a fresh array of length [n],
+   with element number [i] initialized to the result of [f i].
+   In other terms, [Array.init n f] tabulates the results of [f]
+   applied to the integers [0] to [n-1].
+
+   Raise [Invalid_argument] if [n < 0] or [n > Sys.max_array_length].
+   If the return type of [f] is [float], then the maximum
+   size is only [Sys.max_array_length / 2].*/
+@deprecated("Use Core instead. This will be removed in v13")
+let init: (int, int => 'a) => array<'a>
+
+/** [Array.make_matrix dimx dimy e] returns a two-dimensional array
+   (an array of arrays) with first dimension [dimx] and
+   second dimension [dimy]. All the elements of this new matrix
+   are initially physically equal to [e].
+   The element ([x,y]) of a matrix [m] is accessed
+   with the notation [m.(x).(y)].
+
+   Raise [Invalid_argument] if [dimx] or [dimy] is negative or
+   greater than {!Sys.max_array_length}.
+   If the value of [e] is a floating-point number, then the maximum
+   size is only [Sys.max_array_length / 2]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let make_matrix: (int, int, 'a) => array<array<'a>>
+
+/** [Array.append v1 v2] returns a fresh array containing the
+   concatenation of the arrays [v1] and [v2]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let append: (array<'a>, array<'a>) => array<'a>
+
+/** Same as {!Array.append}, but concatenates a list of arrays. */
+@deprecated("Use Core instead. This will be removed in v13")
+let concat: list<array<'a>> => array<'a>
+
+/** [Array.sub a start len] returns a fresh array of length [len],
+   containing the elements number [start] to [start + len - 1]
+   of array [a].
+
+   Raise [Invalid_argument "Array.sub"] if [start] and [len] do not
+   designate a valid subarray of [a]; that is, if
+   [start < 0], or [len < 0], or [start + len > Array.length a]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let sub: (array<'a>, int, int) => array<'a>
+
+/** [Array.copy a] returns a copy of [a], that is, a fresh array
+   containing the same elements as [a]. */
+@deprecated("Use Core instead. This will be removed in v13")
+@send
+external copy: array<'a> => array<'a> = "slice"
+
+/** [Array.fill a ofs len x] modifies the array [a] in place,
+   storing [x] in elements number [ofs] to [ofs + len - 1].
+
+   Raise [Invalid_argument "Array.fill"] if [ofs] and [len] do not
+   designate a valid subarray of [a]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let fill: (array<'a>, int, int, 'a) => unit
+
+/** [Array.blit v1 o1 v2 o2 len] copies [len] elements
+   from array [v1], starting at element number [o1], to array [v2],
+   starting at element number [o2]. It works correctly even if
+   [v1] and [v2] are the same array, and the source and
+   destination chunks overlap.
+
+   Raise [Invalid_argument "Array.blit"] if [o1] and [len] do not
+   designate a valid subarray of [v1], or if [o2] and [len] do not
+   designate a valid subarray of [v2]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let blit: (array<'a>, int, array<'a>, int, int) => unit
+
+/** [Array.to_list a] returns the list of all the elements of [a]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let to_list: array<'a> => list<'a>
+
+/** [Array.of_list l] returns a fresh array containing the elements
+   of [l]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let of_list: list<'a> => array<'a>
+
+/* {1 Iterators} */
+
+/** [Array.iter f a] applies function [f] in turn to all
+   the elements of [a].  It is equivalent to
+   [f a.(0); f a.(1); ...; f a.(Array.length a - 1); ()]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let iter: ('a => unit, array<'a>) => unit
+
+/** Same as {!Array.iter}, but the
+   function is applied with the index of the element as first argument,
+   and the element itself as second argument. */
+@deprecated("Use Core instead. This will be removed in v13")
+let iteri: ((int, 'a) => unit, array<'a>) => unit
+
+/** [Array.map f a] applies function [f] to all the elements of [a],
+   and builds an array with the results returned by [f]:
+   [[| f a.(0); f a.(1); ...; f a.(Array.length a - 1) |]]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let map: ('a => 'b, array<'a>) => array<'b>
+
+/** Same as {!Array.map}, but the
+   function is applied to the index of the element as first argument,
+   and the element itself as second argument. */
+@deprecated("Use Core instead. This will be removed in v13")
+let mapi: ((int, 'a) => 'b, array<'a>) => array<'b>
+
+/** [Array.fold_left f x a] computes
+   [f (... (f (f x a.(0)) a.(1)) ...) a.(n-1)],
+   where [n] is the length of the array [a]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let fold_left: (('a, 'b) => 'a, 'a, array<'b>) => 'a
+
+/** [Array.fold_right f a x] computes
+   [f a.(0) (f a.(1) ( ... (f a.(n-1) x) ...))],
+   where [n] is the length of the array [a]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let fold_right: (('b, 'a) => 'a, array<'b>, 'a) => 'a
+
+/* {1 Iterators on two arrays} */
+
+/** [Array.iter2 f a b] applies function [f] to all the elements of [a]
+   and [b].
+   Raise [Invalid_argument] if the arrays are not the same size.
+   @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let iter2: (('a, 'b) => unit, array<'a>, array<'b>) => unit
+
+/** [Array.map2 f a b] applies function [f] to all the elements of [a]
+   and [b], and builds an array with the results returned by [f]:
+   [[| f a.(0) b.(0); ...; f a.(Array.length a - 1) b.(Array.length b - 1)|]].
+   Raise [Invalid_argument] if the arrays are not the same size.
+   @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let map2: (('a, 'b) => 'c, array<'a>, array<'b>) => array<'c>
+
+/* {1 Array scanning} */
+
+/** [Array.for_all p [|a1; ...; an|]] checks if all elements of the array
+   satisfy the predicate [p]. That is, it returns
+   [(p a1) && (p a2) && ... && (p an)].
+   @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let for_all: ('a => bool, array<'a>) => bool
+
+/** [Array.exists p [|a1; ...; an|]] checks if at least one element of
+    the array satisfies the predicate [p]. That is, it returns
+    [(p a1) || (p a2) || ... || (p an)].
+    @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let exists: ('a => bool, array<'a>) => bool
+
+/** [mem a l] is true if and only if [a] is equal
+   to an element of [l].
+   @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let mem: ('a, array<'a>) => bool
+
+/** Same as {!Array.mem}, but uses physical equality instead of structural
+   equality to compare array elements.
+   @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let memq: ('a, array<'a>) => bool
+
+/* {1 Sorting} */
+
+/** Sort an array in increasing order according to a comparison
+   function.  The comparison function must return 0 if its arguments
+   compare as equal, a positive integer if the first is greater,
+   and a negative integer if the first is smaller (see below for a
+   complete specification).  For example, {!Pervasives.compare} is
+   a suitable comparison function, provided there are no floating-point
+   NaN values in the data.  After calling [Array.sort], the
+   array is sorted in place in increasing order.
+   [Array.sort] is guaranteed to run in constant heap space
+   and (at most) logarithmic stack space.
+
+   The current implementation uses Heap Sort.  It runs in constant
+   stack space.
+
+   Specification of the comparison function:
+   Let [a] be the array and [cmp] the comparison function.  The following
+   must be true for all x, y, z in a :
+-   [cmp x y] > 0 if and only if [cmp y x] < 0
+-   if [cmp x y] >= 0 and [cmp y z] >= 0 then [cmp x z] >= 0
+
+   When [Array.sort] returns, [a] contains the same elements as before,
+   reordered in such a way that for all i and j valid indices of [a] :
+-   [cmp a.(i) a.(j)] >= 0 if and only if i >= j
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let sort: (('a, 'a) => int, array<'a>) => unit
+
+/** Same as {!Array.sort}, but the sorting algorithm is stable (i.e.
+   elements that compare equal are kept in their original order) and
+   not guaranteed to run in constant heap space.
+
+   The current implementation uses Merge Sort. It uses [n/2]
+   words of heap space, where [n] is the length of the array.
+   It is usually faster than the current implementation of {!Array.sort}.
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let stable_sort: (('a, 'a) => int, array<'a>) => unit
+
+/** Same as {!Array.sort} or {!Array.stable_sort}, whichever is faster
+    on typical input.
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let fast_sort: (('a, 'a) => int, array<'a>) => unit
+
+@deprecated("Use Core instead. This will be removed in v13")
+external unsafe_get: (array<'a>, int) => 'a = "%array_unsafe_get"
+
+@deprecated("Use Core instead. This will be removed in v13")
+external unsafe_set: (array<'a>, int, 'a) => unit = "%array_unsafe_set"
diff --git a/lib/js/Hashtbl.js b/tests/tests/src/ocaml_compat/Ocaml_Hashtbl.js
similarity index 52%
rename from lib/js/Hashtbl.js
rename to tests/tests/src/ocaml_compat/Ocaml_Hashtbl.js
index 90e167d498..bdc1ba676a 100644
--- a/lib/js/Hashtbl.js
+++ b/tests/tests/src/ocaml_compat/Ocaml_Hashtbl.js
@@ -1,6 +1,7 @@
+// Generated by ReScript, PLEASE EDIT WITH CARE
 'use strict';
 
-let Primitive_hash = require("./Primitive_hash.js");
+let Primitive_hash = require("rescript/lib/js/Primitive_hash.js");
 
 function hash(x) {
   return Primitive_hash.hash(10, 100, 0, x);
diff --git a/runtime/Hashtbl.res b/tests/tests/src/ocaml_compat/Ocaml_Hashtbl.res
similarity index 100%
rename from runtime/Hashtbl.res
rename to tests/tests/src/ocaml_compat/Ocaml_Hashtbl.res
diff --git a/runtime/Hashtbl.resi b/tests/tests/src/ocaml_compat/Ocaml_Hashtbl.resi
similarity index 100%
rename from runtime/Hashtbl.resi
rename to tests/tests/src/ocaml_compat/Ocaml_Hashtbl.resi
diff --git a/tests/tests/src/ocaml_compat/Ocaml_List.js b/tests/tests/src/ocaml_compat/Ocaml_List.js
new file mode 100644
index 0000000000..e0dbc3d73e
--- /dev/null
+++ b/tests/tests/src/ocaml_compat/Ocaml_List.js
@@ -0,0 +1,1629 @@
+// Generated by ReScript, PLEASE EDIT WITH CARE
+'use strict';
+
+let Pervasives = require("rescript/lib/js/Pervasives.js");
+let Primitive_option = require("rescript/lib/js/Primitive_option.js");
+
+function length(l) {
+  let _len = 0;
+  let _param = l;
+  while (true) {
+    let param = _param;
+    let len = _len;
+    if (!param) {
+      return len;
+    }
+    _param = param.tl;
+    _len = len + 1 | 0;
+    continue;
+  };
+}
+
+function cons(a, l) {
+  return {
+    hd: a,
+    tl: l
+  };
+}
+
+function hd(param) {
+  if (param) {
+    return param.hd;
+  } else {
+    return Pervasives.failwith("hd");
+  }
+}
+
+function tl(param) {
+  if (param) {
+    return param.tl;
+  } else {
+    return Pervasives.failwith("tl");
+  }
+}
+
+function nth(l, n) {
+  if (n < 0) {
+    return Pervasives.invalid_arg("List.nth");
+  }
+  let _l = l;
+  let _n = n;
+  while (true) {
+    let n$1 = _n;
+    let l$1 = _l;
+    if (!l$1) {
+      return Pervasives.failwith("nth");
+    }
+    if (n$1 === 0) {
+      return l$1.hd;
+    }
+    _n = n$1 - 1 | 0;
+    _l = l$1.tl;
+    continue;
+  };
+}
+
+function nth_opt(l, n) {
+  if (n < 0) {
+    return Pervasives.invalid_arg("List.nth");
+  }
+  let _l = l;
+  let _n = n;
+  while (true) {
+    let n$1 = _n;
+    let l$1 = _l;
+    if (!l$1) {
+      return;
+    }
+    if (n$1 === 0) {
+      return Primitive_option.some(l$1.hd);
+    }
+    _n = n$1 - 1 | 0;
+    _l = l$1.tl;
+    continue;
+  };
+}
+
+function rev_append(_l1, _l2) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      return l2;
+    }
+    _l2 = {
+      hd: l1.hd,
+      tl: l2
+    };
+    _l1 = l1.tl;
+    continue;
+  };
+}
+
+function rev(l) {
+  return rev_append(l, /* [] */0);
+}
+
+function init_tailrec_aux(_acc, _i, n, f) {
+  while (true) {
+    let i = _i;
+    let acc = _acc;
+    if (i >= n) {
+      return acc;
+    }
+    _i = i + 1 | 0;
+    _acc = {
+      hd: f(i),
+      tl: acc
+    };
+    continue;
+  };
+}
+
+function init_aux(i, n, f) {
+  if (i >= n) {
+    return /* [] */0;
+  }
+  let r = f(i);
+  return {
+    hd: r,
+    tl: init_aux(i + 1 | 0, n, f)
+  };
+}
+
+function init(len, f) {
+  if (len < 0) {
+    return Pervasives.invalid_arg("List.init");
+  } else if (len > 10000) {
+    return rev_append(init_tailrec_aux(/* [] */0, 0, len, f), /* [] */0);
+  } else {
+    return init_aux(0, len, f);
+  }
+}
+
+function flatten(param) {
+  if (param) {
+    return Pervasives.$at(param.hd, flatten(param.tl));
+  } else {
+    return /* [] */0;
+  }
+}
+
+function map(f, param) {
+  if (!param) {
+    return /* [] */0;
+  }
+  let r = f(param.hd);
+  return {
+    hd: r,
+    tl: map(f, param.tl)
+  };
+}
+
+function mapi(i, f, param) {
+  if (!param) {
+    return /* [] */0;
+  }
+  let r = f(i, param.hd);
+  return {
+    hd: r,
+    tl: mapi(i + 1 | 0, f, param.tl)
+  };
+}
+
+function mapi$1(f, l) {
+  return mapi(0, f, l);
+}
+
+function rev_map(f, l) {
+  let _accu = /* [] */0;
+  let _param = l;
+  while (true) {
+    let param = _param;
+    let accu = _accu;
+    if (!param) {
+      return accu;
+    }
+    _param = param.tl;
+    _accu = {
+      hd: f(param.hd),
+      tl: accu
+    };
+    continue;
+  };
+}
+
+function iter(f, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return;
+    }
+    f(param.hd);
+    _param = param.tl;
+    continue;
+  };
+}
+
+function iteri(f, l) {
+  let _i = 0;
+  let _param = l;
+  while (true) {
+    let param = _param;
+    let i = _i;
+    if (!param) {
+      return;
+    }
+    f(i, param.hd);
+    _param = param.tl;
+    _i = i + 1 | 0;
+    continue;
+  };
+}
+
+function fold_left(f, _accu, _l) {
+  while (true) {
+    let l = _l;
+    let accu = _accu;
+    if (!l) {
+      return accu;
+    }
+    _l = l.tl;
+    _accu = f(accu, l.hd);
+    continue;
+  };
+}
+
+function fold_right(f, l, accu) {
+  if (l) {
+    return f(l.hd, fold_right(f, l.tl, accu));
+  } else {
+    return accu;
+  }
+}
+
+function map2(f, l1, l2) {
+  if (!l1) {
+    if (l2) {
+      return Pervasives.invalid_arg("List.map2");
+    } else {
+      return /* [] */0;
+    }
+  }
+  if (!l2) {
+    return Pervasives.invalid_arg("List.map2");
+  }
+  let r = f(l1.hd, l2.hd);
+  return {
+    hd: r,
+    tl: map2(f, l1.tl, l2.tl)
+  };
+}
+
+function rev_map2(f, l1, l2) {
+  let _accu = /* [] */0;
+  let _l1 = l1;
+  let _l2 = l2;
+  while (true) {
+    let l2$1 = _l2;
+    let l1$1 = _l1;
+    let accu = _accu;
+    if (!l1$1) {
+      if (l2$1) {
+        return Pervasives.invalid_arg("List.rev_map2");
+      } else {
+        return accu;
+      }
+    }
+    if (!l2$1) {
+      return Pervasives.invalid_arg("List.rev_map2");
+    }
+    _l2 = l2$1.tl;
+    _l1 = l1$1.tl;
+    _accu = {
+      hd: f(l1$1.hd, l2$1.hd),
+      tl: accu
+    };
+    continue;
+  };
+}
+
+function iter2(f, _l1, _l2) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      if (l2) {
+        return Pervasives.invalid_arg("List.iter2");
+      } else {
+        return;
+      }
+    }
+    if (!l2) {
+      return Pervasives.invalid_arg("List.iter2");
+    }
+    f(l1.hd, l2.hd);
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
+}
+
+function fold_left2(f, _accu, _l1, _l2) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    let accu = _accu;
+    if (!l1) {
+      if (l2) {
+        return Pervasives.invalid_arg("List.fold_left2");
+      } else {
+        return accu;
+      }
+    }
+    if (!l2) {
+      return Pervasives.invalid_arg("List.fold_left2");
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    _accu = f(accu, l1.hd, l2.hd);
+    continue;
+  };
+}
+
+function fold_right2(f, l1, l2, accu) {
+  if (l1) {
+    if (l2) {
+      return f(l1.hd, l2.hd, fold_right2(f, l1.tl, l2.tl, accu));
+    } else {
+      return Pervasives.invalid_arg("List.fold_right2");
+    }
+  } else if (l2) {
+    return Pervasives.invalid_arg("List.fold_right2");
+  } else {
+    return accu;
+  }
+}
+
+function for_all(p, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return true;
+    }
+    if (!p(param.hd)) {
+      return false;
+    }
+    _param = param.tl;
+    continue;
+  };
+}
+
+function exists(p, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return false;
+    }
+    if (p(param.hd)) {
+      return true;
+    }
+    _param = param.tl;
+    continue;
+  };
+}
+
+function for_all2(p, _l1, _l2) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      if (l2) {
+        return Pervasives.invalid_arg("List.for_all2");
+      } else {
+        return true;
+      }
+    }
+    if (!l2) {
+      return Pervasives.invalid_arg("List.for_all2");
+    }
+    if (!p(l1.hd, l2.hd)) {
+      return false;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
+}
+
+function exists2(p, _l1, _l2) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      if (l2) {
+        return Pervasives.invalid_arg("List.exists2");
+      } else {
+        return false;
+      }
+    }
+    if (!l2) {
+      return Pervasives.invalid_arg("List.exists2");
+    }
+    if (p(l1.hd, l2.hd)) {
+      return true;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
+}
+
+function mem(x, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return false;
+    }
+    if (param.hd === x) {
+      return true;
+    }
+    _param = param.tl;
+    continue;
+  };
+}
+
+function memq(x, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return false;
+    }
+    if (param.hd === x) {
+      return true;
+    }
+    _param = param.tl;
+    continue;
+  };
+}
+
+function assoc(x, _param) {
+  while (true) {
+    let param = _param;
+    if (param) {
+      let match = param.hd;
+      if (match[0] === x) {
+        return match[1];
+      }
+      _param = param.tl;
+      continue;
+    }
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
+  };
+}
+
+function assoc_opt(x, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return;
+    }
+    let match = param.hd;
+    if (match[0] === x) {
+      return Primitive_option.some(match[1]);
+    }
+    _param = param.tl;
+    continue;
+  };
+}
+
+function assq(x, _param) {
+  while (true) {
+    let param = _param;
+    if (param) {
+      let match = param.hd;
+      if (match[0] === x) {
+        return match[1];
+      }
+      _param = param.tl;
+      continue;
+    }
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
+  };
+}
+
+function assq_opt(x, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return;
+    }
+    let match = param.hd;
+    if (match[0] === x) {
+      return Primitive_option.some(match[1]);
+    }
+    _param = param.tl;
+    continue;
+  };
+}
+
+function mem_assoc(x, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return false;
+    }
+    if (param.hd[0] === x) {
+      return true;
+    }
+    _param = param.tl;
+    continue;
+  };
+}
+
+function mem_assq(x, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return false;
+    }
+    if (param.hd[0] === x) {
+      return true;
+    }
+    _param = param.tl;
+    continue;
+  };
+}
+
+function remove_assoc(x, param) {
+  if (!param) {
+    return /* [] */0;
+  }
+  let l = param.tl;
+  let pair = param.hd;
+  if (pair[0] === x) {
+    return l;
+  } else {
+    return {
+      hd: pair,
+      tl: remove_assoc(x, l)
+    };
+  }
+}
+
+function remove_assq(x, param) {
+  if (!param) {
+    return /* [] */0;
+  }
+  let l = param.tl;
+  let pair = param.hd;
+  if (pair[0] === x) {
+    return l;
+  } else {
+    return {
+      hd: pair,
+      tl: remove_assq(x, l)
+    };
+  }
+}
+
+function find(p, _param) {
+  while (true) {
+    let param = _param;
+    if (param) {
+      let x = param.hd;
+      if (p(x)) {
+        return x;
+      }
+      _param = param.tl;
+      continue;
+    }
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
+  };
+}
+
+function find_opt(p, _param) {
+  while (true) {
+    let param = _param;
+    if (!param) {
+      return;
+    }
+    let x = param.hd;
+    if (p(x)) {
+      return Primitive_option.some(x);
+    }
+    _param = param.tl;
+    continue;
+  };
+}
+
+function find_all(p, l) {
+  let _accu = /* [] */0;
+  let _param = l;
+  while (true) {
+    let param = _param;
+    let accu = _accu;
+    if (!param) {
+      return rev_append(accu, /* [] */0);
+    }
+    let l$1 = param.tl;
+    let x = param.hd;
+    if (p(x)) {
+      _param = l$1;
+      _accu = {
+        hd: x,
+        tl: accu
+      };
+      continue;
+    }
+    _param = l$1;
+    continue;
+  };
+}
+
+function partition(p, l) {
+  let _yes = /* [] */0;
+  let _no = /* [] */0;
+  let _param = l;
+  while (true) {
+    let param = _param;
+    let no = _no;
+    let yes = _yes;
+    if (!param) {
+      return [
+        rev_append(yes, /* [] */0),
+        rev_append(no, /* [] */0)
+      ];
+    }
+    let l$1 = param.tl;
+    let x = param.hd;
+    if (p(x)) {
+      _param = l$1;
+      _yes = {
+        hd: x,
+        tl: yes
+      };
+      continue;
+    }
+    _param = l$1;
+    _no = {
+      hd: x,
+      tl: no
+    };
+    continue;
+  };
+}
+
+function split(param) {
+  if (!param) {
+    return [
+      /* [] */0,
+      /* [] */0
+    ];
+  }
+  let match = param.hd;
+  let match$1 = split(param.tl);
+  return [
+    {
+      hd: match[0],
+      tl: match$1[0]
+    },
+    {
+      hd: match[1],
+      tl: match$1[1]
+    }
+  ];
+}
+
+function combine(l1, l2) {
+  if (l1) {
+    if (l2) {
+      return {
+        hd: [
+          l1.hd,
+          l2.hd
+        ],
+        tl: combine(l1.tl, l2.tl)
+      };
+    } else {
+      return Pervasives.invalid_arg("List.combine");
+    }
+  } else if (l2) {
+    return Pervasives.invalid_arg("List.combine");
+  } else {
+    return /* [] */0;
+  }
+}
+
+function merge(cmp, l1, l2) {
+  if (!l1) {
+    return l2;
+  }
+  if (!l2) {
+    return l1;
+  }
+  let h2 = l2.hd;
+  let h1 = l1.hd;
+  if (cmp(h1, h2) <= 0) {
+    return {
+      hd: h1,
+      tl: merge(cmp, l1.tl, l2)
+    };
+  } else {
+    return {
+      hd: h2,
+      tl: merge(cmp, l1, l2.tl)
+    };
+  }
+}
+
+function chop(_k, _l) {
+  while (true) {
+    let l = _l;
+    let k = _k;
+    if (k === 0) {
+      return l;
+    }
+    if (l) {
+      _l = l.tl;
+      _k = k - 1 | 0;
+      continue;
+    }
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "Ocaml_List.res",
+        411,
+        11
+      ],
+      Error: new Error()
+    };
+  };
+}
+
+function stable_sort(cmp, l) {
+  let sort = (n, l) => {
+    if (n !== 2) {
+      if (n === 3 && l) {
+        let match = l.tl;
+        if (match) {
+          let match$1 = match.tl;
+          if (match$1) {
+            let x3 = match$1.hd;
+            let x2 = match.hd;
+            let x1 = l.hd;
+            if (cmp(x1, x2) <= 0) {
+              if (cmp(x2, x3) <= 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x2,
+                    tl: {
+                      hd: x3,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              } else if (cmp(x1, x3) <= 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x3,
+                    tl: {
+                      hd: x2,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              } else {
+                return {
+                  hd: x3,
+                  tl: {
+                    hd: x1,
+                    tl: {
+                      hd: x2,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              }
+            } else if (cmp(x1, x3) <= 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x1,
+                  tl: {
+                    hd: x3,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            } else if (cmp(x2, x3) <= 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x3,
+                  tl: {
+                    hd: x1,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            } else {
+              return {
+                hd: x3,
+                tl: {
+                  hd: x2,
+                  tl: {
+                    hd: x1,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            }
+          }
+          
+        }
+        
+      }
+      
+    } else if (l) {
+      let match$2 = l.tl;
+      if (match$2) {
+        let x2$1 = match$2.hd;
+        let x1$1 = l.hd;
+        if (cmp(x1$1, x2$1) <= 0) {
+          return {
+            hd: x1$1,
+            tl: {
+              hd: x2$1,
+              tl: /* [] */0
+            }
+          };
+        } else {
+          return {
+            hd: x2$1,
+            tl: {
+              hd: x1$1,
+              tl: /* [] */0
+            }
+          };
+        }
+      }
+      
+    }
+    let n1 = (n >> 1);
+    let n2 = n - n1 | 0;
+    let l2 = chop(n1, l);
+    let s1 = rev_sort(n1, l);
+    let s2 = rev_sort(n2, l2);
+    let _l1 = s1;
+    let _l2 = s2;
+    let _accu = /* [] */0;
+    while (true) {
+      let accu = _accu;
+      let l2$1 = _l2;
+      let l1 = _l1;
+      if (!l1) {
+        return rev_append(l2$1, accu);
+      }
+      if (!l2$1) {
+        return rev_append(l1, accu);
+      }
+      let h2 = l2$1.hd;
+      let h1 = l1.hd;
+      if (cmp(h1, h2) > 0) {
+        _accu = {
+          hd: h1,
+          tl: accu
+        };
+        _l1 = l1.tl;
+        continue;
+      }
+      _accu = {
+        hd: h2,
+        tl: accu
+      };
+      _l2 = l2$1.tl;
+      continue;
+    };
+  };
+  let rev_sort = (n, l) => {
+    if (n !== 2) {
+      if (n === 3 && l) {
+        let match = l.tl;
+        if (match) {
+          let match$1 = match.tl;
+          if (match$1) {
+            let x3 = match$1.hd;
+            let x2 = match.hd;
+            let x1 = l.hd;
+            if (cmp(x1, x2) > 0) {
+              if (cmp(x2, x3) > 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x2,
+                    tl: {
+                      hd: x3,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              } else if (cmp(x1, x3) > 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x3,
+                    tl: {
+                      hd: x2,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              } else {
+                return {
+                  hd: x3,
+                  tl: {
+                    hd: x1,
+                    tl: {
+                      hd: x2,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              }
+            } else if (cmp(x1, x3) > 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x1,
+                  tl: {
+                    hd: x3,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            } else if (cmp(x2, x3) > 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x3,
+                  tl: {
+                    hd: x1,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            } else {
+              return {
+                hd: x3,
+                tl: {
+                  hd: x2,
+                  tl: {
+                    hd: x1,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            }
+          }
+          
+        }
+        
+      }
+      
+    } else if (l) {
+      let match$2 = l.tl;
+      if (match$2) {
+        let x2$1 = match$2.hd;
+        let x1$1 = l.hd;
+        if (cmp(x1$1, x2$1) > 0) {
+          return {
+            hd: x1$1,
+            tl: {
+              hd: x2$1,
+              tl: /* [] */0
+            }
+          };
+        } else {
+          return {
+            hd: x2$1,
+            tl: {
+              hd: x1$1,
+              tl: /* [] */0
+            }
+          };
+        }
+      }
+      
+    }
+    let n1 = (n >> 1);
+    let n2 = n - n1 | 0;
+    let l2 = chop(n1, l);
+    let s1 = sort(n1, l);
+    let s2 = sort(n2, l2);
+    let _l1 = s1;
+    let _l2 = s2;
+    let _accu = /* [] */0;
+    while (true) {
+      let accu = _accu;
+      let l2$1 = _l2;
+      let l1 = _l1;
+      if (!l1) {
+        return rev_append(l2$1, accu);
+      }
+      if (!l2$1) {
+        return rev_append(l1, accu);
+      }
+      let h2 = l2$1.hd;
+      let h1 = l1.hd;
+      if (cmp(h1, h2) <= 0) {
+        _accu = {
+          hd: h1,
+          tl: accu
+        };
+        _l1 = l1.tl;
+        continue;
+      }
+      _accu = {
+        hd: h2,
+        tl: accu
+      };
+      _l2 = l2$1.tl;
+      continue;
+    };
+  };
+  let len = length(l);
+  if (len < 2) {
+    return l;
+  } else {
+    return sort(len, l);
+  }
+}
+
+function sort_uniq(cmp, l) {
+  let sort = (n, l) => {
+    if (n !== 2) {
+      if (n === 3 && l) {
+        let match = l.tl;
+        if (match) {
+          let match$1 = match.tl;
+          if (match$1) {
+            let x3 = match$1.hd;
+            let x2 = match.hd;
+            let x1 = l.hd;
+            let c = cmp(x1, x2);
+            if (c === 0) {
+              let c$1 = cmp(x2, x3);
+              if (c$1 === 0) {
+                return {
+                  hd: x2,
+                  tl: /* [] */0
+                };
+              } else if (c$1 < 0) {
+                return {
+                  hd: x2,
+                  tl: {
+                    hd: x3,
+                    tl: /* [] */0
+                  }
+                };
+              } else {
+                return {
+                  hd: x3,
+                  tl: {
+                    hd: x2,
+                    tl: /* [] */0
+                  }
+                };
+              }
+            }
+            if (c < 0) {
+              let c$2 = cmp(x2, x3);
+              if (c$2 === 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x2,
+                    tl: /* [] */0
+                  }
+                };
+              }
+              if (c$2 < 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x2,
+                    tl: {
+                      hd: x3,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              }
+              let c$3 = cmp(x1, x3);
+              if (c$3 === 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x2,
+                    tl: /* [] */0
+                  }
+                };
+              } else if (c$3 < 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x3,
+                    tl: {
+                      hd: x2,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              } else {
+                return {
+                  hd: x3,
+                  tl: {
+                    hd: x1,
+                    tl: {
+                      hd: x2,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              }
+            }
+            let c$4 = cmp(x1, x3);
+            if (c$4 === 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x1,
+                  tl: /* [] */0
+                }
+              };
+            }
+            if (c$4 < 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x1,
+                  tl: {
+                    hd: x3,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            }
+            let c$5 = cmp(x2, x3);
+            if (c$5 === 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x1,
+                  tl: /* [] */0
+                }
+              };
+            } else if (c$5 < 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x3,
+                  tl: {
+                    hd: x1,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            } else {
+              return {
+                hd: x3,
+                tl: {
+                  hd: x2,
+                  tl: {
+                    hd: x1,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            }
+          }
+          
+        }
+        
+      }
+      
+    } else if (l) {
+      let match$2 = l.tl;
+      if (match$2) {
+        let x2$1 = match$2.hd;
+        let x1$1 = l.hd;
+        let c$6 = cmp(x1$1, x2$1);
+        if (c$6 === 0) {
+          return {
+            hd: x1$1,
+            tl: /* [] */0
+          };
+        } else if (c$6 < 0) {
+          return {
+            hd: x1$1,
+            tl: {
+              hd: x2$1,
+              tl: /* [] */0
+            }
+          };
+        } else {
+          return {
+            hd: x2$1,
+            tl: {
+              hd: x1$1,
+              tl: /* [] */0
+            }
+          };
+        }
+      }
+      
+    }
+    let n1 = (n >> 1);
+    let n2 = n - n1 | 0;
+    let l2 = chop(n1, l);
+    let s1 = rev_sort(n1, l);
+    let s2 = rev_sort(n2, l2);
+    let _l1 = s1;
+    let _l2 = s2;
+    let _accu = /* [] */0;
+    while (true) {
+      let accu = _accu;
+      let l2$1 = _l2;
+      let l1 = _l1;
+      if (!l1) {
+        return rev_append(l2$1, accu);
+      }
+      if (!l2$1) {
+        return rev_append(l1, accu);
+      }
+      let t2 = l2$1.tl;
+      let h2 = l2$1.hd;
+      let t1 = l1.tl;
+      let h1 = l1.hd;
+      let c$7 = cmp(h1, h2);
+      if (c$7 === 0) {
+        _accu = {
+          hd: h1,
+          tl: accu
+        };
+        _l2 = t2;
+        _l1 = t1;
+        continue;
+      }
+      if (c$7 > 0) {
+        _accu = {
+          hd: h1,
+          tl: accu
+        };
+        _l1 = t1;
+        continue;
+      }
+      _accu = {
+        hd: h2,
+        tl: accu
+      };
+      _l2 = t2;
+      continue;
+    };
+  };
+  let rev_sort = (n, l) => {
+    if (n !== 2) {
+      if (n === 3 && l) {
+        let match = l.tl;
+        if (match) {
+          let match$1 = match.tl;
+          if (match$1) {
+            let x3 = match$1.hd;
+            let x2 = match.hd;
+            let x1 = l.hd;
+            let c = cmp(x1, x2);
+            if (c === 0) {
+              let c$1 = cmp(x2, x3);
+              if (c$1 === 0) {
+                return {
+                  hd: x2,
+                  tl: /* [] */0
+                };
+              } else if (c$1 > 0) {
+                return {
+                  hd: x2,
+                  tl: {
+                    hd: x3,
+                    tl: /* [] */0
+                  }
+                };
+              } else {
+                return {
+                  hd: x3,
+                  tl: {
+                    hd: x2,
+                    tl: /* [] */0
+                  }
+                };
+              }
+            }
+            if (c > 0) {
+              let c$2 = cmp(x2, x3);
+              if (c$2 === 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x2,
+                    tl: /* [] */0
+                  }
+                };
+              }
+              if (c$2 > 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x2,
+                    tl: {
+                      hd: x3,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              }
+              let c$3 = cmp(x1, x3);
+              if (c$3 === 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x2,
+                    tl: /* [] */0
+                  }
+                };
+              } else if (c$3 > 0) {
+                return {
+                  hd: x1,
+                  tl: {
+                    hd: x3,
+                    tl: {
+                      hd: x2,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              } else {
+                return {
+                  hd: x3,
+                  tl: {
+                    hd: x1,
+                    tl: {
+                      hd: x2,
+                      tl: /* [] */0
+                    }
+                  }
+                };
+              }
+            }
+            let c$4 = cmp(x1, x3);
+            if (c$4 === 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x1,
+                  tl: /* [] */0
+                }
+              };
+            }
+            if (c$4 > 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x1,
+                  tl: {
+                    hd: x3,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            }
+            let c$5 = cmp(x2, x3);
+            if (c$5 === 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x1,
+                  tl: /* [] */0
+                }
+              };
+            } else if (c$5 > 0) {
+              return {
+                hd: x2,
+                tl: {
+                  hd: x3,
+                  tl: {
+                    hd: x1,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            } else {
+              return {
+                hd: x3,
+                tl: {
+                  hd: x2,
+                  tl: {
+                    hd: x1,
+                    tl: /* [] */0
+                  }
+                }
+              };
+            }
+          }
+          
+        }
+        
+      }
+      
+    } else if (l) {
+      let match$2 = l.tl;
+      if (match$2) {
+        let x2$1 = match$2.hd;
+        let x1$1 = l.hd;
+        let c$6 = cmp(x1$1, x2$1);
+        if (c$6 === 0) {
+          return {
+            hd: x1$1,
+            tl: /* [] */0
+          };
+        } else if (c$6 > 0) {
+          return {
+            hd: x1$1,
+            tl: {
+              hd: x2$1,
+              tl: /* [] */0
+            }
+          };
+        } else {
+          return {
+            hd: x2$1,
+            tl: {
+              hd: x1$1,
+              tl: /* [] */0
+            }
+          };
+        }
+      }
+      
+    }
+    let n1 = (n >> 1);
+    let n2 = n - n1 | 0;
+    let l2 = chop(n1, l);
+    let s1 = sort(n1, l);
+    let s2 = sort(n2, l2);
+    let _l1 = s1;
+    let _l2 = s2;
+    let _accu = /* [] */0;
+    while (true) {
+      let accu = _accu;
+      let l2$1 = _l2;
+      let l1 = _l1;
+      if (!l1) {
+        return rev_append(l2$1, accu);
+      }
+      if (!l2$1) {
+        return rev_append(l1, accu);
+      }
+      let t2 = l2$1.tl;
+      let h2 = l2$1.hd;
+      let t1 = l1.tl;
+      let h1 = l1.hd;
+      let c$7 = cmp(h1, h2);
+      if (c$7 === 0) {
+        _accu = {
+          hd: h1,
+          tl: accu
+        };
+        _l2 = t2;
+        _l1 = t1;
+        continue;
+      }
+      if (c$7 < 0) {
+        _accu = {
+          hd: h1,
+          tl: accu
+        };
+        _l1 = t1;
+        continue;
+      }
+      _accu = {
+        hd: h2,
+        tl: accu
+      };
+      _l2 = t2;
+      continue;
+    };
+  };
+  let len = length(l);
+  if (len < 2) {
+    return l;
+  } else {
+    return sort(len, l);
+  }
+}
+
+function compare_lengths(_l1, _l2) {
+  while (true) {
+    let l2 = _l2;
+    let l1 = _l1;
+    if (!l1) {
+      if (l2) {
+        return -1;
+      } else {
+        return 0;
+      }
+    }
+    if (!l2) {
+      return 1;
+    }
+    _l2 = l2.tl;
+    _l1 = l1.tl;
+    continue;
+  };
+}
+
+function compare_length_with(_l, _n) {
+  while (true) {
+    let n = _n;
+    let l = _l;
+    if (!l) {
+      if (n === 0) {
+        return 0;
+      } else if (n > 0) {
+        return -1;
+      } else {
+        return 1;
+      }
+    }
+    if (n <= 0) {
+      return 1;
+    }
+    _n = n - 1 | 0;
+    _l = l.tl;
+    continue;
+  };
+}
+
+let append = Pervasives.$at;
+
+let concat = flatten;
+
+let filter = find_all;
+
+let sort = stable_sort;
+
+let fast_sort = stable_sort;
+
+exports.length = length;
+exports.compare_lengths = compare_lengths;
+exports.compare_length_with = compare_length_with;
+exports.cons = cons;
+exports.hd = hd;
+exports.tl = tl;
+exports.nth = nth;
+exports.nth_opt = nth_opt;
+exports.rev = rev;
+exports.init = init;
+exports.append = append;
+exports.rev_append = rev_append;
+exports.concat = concat;
+exports.flatten = flatten;
+exports.iter = iter;
+exports.iteri = iteri;
+exports.map = map;
+exports.mapi = mapi$1;
+exports.rev_map = rev_map;
+exports.fold_left = fold_left;
+exports.fold_right = fold_right;
+exports.iter2 = iter2;
+exports.map2 = map2;
+exports.rev_map2 = rev_map2;
+exports.fold_left2 = fold_left2;
+exports.fold_right2 = fold_right2;
+exports.for_all = for_all;
+exports.exists = exists;
+exports.for_all2 = for_all2;
+exports.exists2 = exists2;
+exports.mem = mem;
+exports.memq = memq;
+exports.find = find;
+exports.find_opt = find_opt;
+exports.filter = filter;
+exports.find_all = find_all;
+exports.partition = partition;
+exports.assoc = assoc;
+exports.assoc_opt = assoc_opt;
+exports.assq = assq;
+exports.assq_opt = assq_opt;
+exports.mem_assoc = mem_assoc;
+exports.mem_assq = mem_assq;
+exports.remove_assoc = remove_assoc;
+exports.remove_assq = remove_assq;
+exports.split = split;
+exports.combine = combine;
+exports.sort = sort;
+exports.stable_sort = stable_sort;
+exports.fast_sort = fast_sort;
+exports.sort_uniq = sort_uniq;
+exports.merge = merge;
+/* No side effect */
diff --git a/tests/tests/src/ocaml_compat/Ocaml_List.res b/tests/tests/src/ocaml_compat/Ocaml_List.res
new file mode 100644
index 0000000000..334b2f8937
--- /dev/null
+++ b/tests/tests/src/ocaml_compat/Ocaml_List.res
@@ -0,0 +1,740 @@
+// FIXME:
+//   This exists for compatibility reason.
+//   Move this into Pervasives or Core
+
+// Below is all deprecated and should be removed in v13
+
+type t<'a> = list<'a>
+
+let rec length_aux = (len, param) =>
+  switch param {
+  | list{} => len
+  | list{_, ...l} => length_aux(len + 1, l)
+  }
+
+let length = l => length_aux(0, l)
+
+let cons = (a, l) => list{a, ...l}
+
+let hd = param =>
+  switch param {
+  | list{} => failwith("hd")
+  | list{a, ..._} => a
+  }
+
+let tl = param =>
+  switch param {
+  | list{} => failwith("tl")
+  | list{_, ...l} => l
+  }
+
+let nth = (l, n) =>
+  if n < 0 {
+    invalid_arg("List.nth")
+  } else {
+    let rec nth_aux = (l, n) =>
+      switch l {
+      | list{} => failwith("nth")
+      | list{a, ...l} =>
+        if n == 0 {
+          a
+        } else {
+          nth_aux(l, n - 1)
+        }
+      }
+    nth_aux(l, n)
+  }
+
+let nth_opt = (l, n) =>
+  if n < 0 {
+    invalid_arg("List.nth")
+  } else {
+    let rec nth_aux = (l, n) =>
+      switch l {
+      | list{} => None
+      | list{a, ...l} =>
+        if n == 0 {
+          Some(a)
+        } else {
+          nth_aux(l, n - 1)
+        }
+      }
+    nth_aux(l, n)
+  }
+
+let append = \"@"
+
+let rec rev_append = (l1, l2) =>
+  switch l1 {
+  | list{} => l2
+  | list{a, ...l} => rev_append(l, list{a, ...l2})
+  }
+
+let rev = l => rev_append(l, list{})
+
+let rec init_tailrec_aux = (acc, i, n, f) =>
+  if i >= n {
+    acc
+  } else {
+    init_tailrec_aux(list{f(i), ...acc}, i + 1, n, f)
+  }
+
+let rec init_aux = (i, n, f) =>
+  if i >= n {
+    list{}
+  } else {
+    let r = f(i)
+    list{r, ...init_aux(i + 1, n, f)}
+  }
+
+let init = (len, f) =>
+  if len < 0 {
+    invalid_arg("List.init")
+  } else if len > 10_000 {
+    rev(init_tailrec_aux(list{}, 0, len, f))
+  } else {
+    init_aux(0, len, f)
+  }
+
+let rec flatten = param =>
+  switch param {
+  | list{} => list{}
+  | list{l, ...r} => \"@"(l, flatten(r))
+  }
+
+let concat = flatten
+
+let rec map = (f, param) =>
+  switch param {
+  | list{} => list{}
+  | list{a, ...l} =>
+    let r = f(a)
+    list{r, ...map(f, l)}
+  }
+
+let rec mapi = (i, f, param) =>
+  switch param {
+  | list{} => list{}
+  | list{a, ...l} =>
+    let r = f(i, a)
+    list{r, ...mapi(i + 1, f, l)}
+  }
+
+let mapi = (f, l) => mapi(0, f, l)
+
+let rev_map = (f, l) => {
+  let rec rmap_f = (accu, param) =>
+    switch param {
+    | list{} => accu
+    | list{a, ...l} => rmap_f(list{f(a), ...accu}, l)
+    }
+
+  rmap_f(list{}, l)
+}
+
+let rec iter = (f, param) =>
+  switch param {
+  | list{} => ()
+  | list{a, ...l} =>
+    f(a)
+    iter(f, l)
+  }
+
+let rec iteri = (i, f, param) =>
+  switch param {
+  | list{} => ()
+  | list{a, ...l} =>
+    f(i, a)
+    iteri(i + 1, f, l)
+  }
+
+let iteri = (f, l) => iteri(0, f, l)
+
+let rec fold_left = (f, accu, l) =>
+  switch l {
+  | list{} => accu
+  | list{a, ...l} => fold_left(f, f(accu, a), l)
+  }
+
+let rec fold_right = (f, l, accu) =>
+  switch l {
+  | list{} => accu
+  | list{a, ...l} => f(a, fold_right(f, l, accu))
+  }
+
+let rec map2 = (f, l1, l2) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => list{}
+  | (list{a1, ...l1}, list{a2, ...l2}) =>
+    let r = f(a1, a2)
+    list{r, ...map2(f, l1, l2)}
+  | (_, _) => invalid_arg("List.map2")
+  }
+
+let rev_map2 = (f, l1, l2) => {
+  let rec rmap2_f = (accu, l1, l2) =>
+    switch (l1, l2) {
+    | (list{}, list{}) => accu
+    | (list{a1, ...l1}, list{a2, ...l2}) => rmap2_f(list{f(a1, a2), ...accu}, l1, l2)
+    | (_, _) => invalid_arg("List.rev_map2")
+    }
+
+  rmap2_f(list{}, l1, l2)
+}
+
+let rec iter2 = (f, l1, l2) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => ()
+  | (list{a1, ...l1}, list{a2, ...l2}) =>
+    f(a1, a2)
+    iter2(f, l1, l2)
+  | (_, _) => invalid_arg("List.iter2")
+  }
+
+let rec fold_left2 = (f, accu, l1, l2) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => accu
+  | (list{a1, ...l1}, list{a2, ...l2}) => fold_left2(f, f(accu, a1, a2), l1, l2)
+  | (_, _) => invalid_arg("List.fold_left2")
+  }
+
+let rec fold_right2 = (f, l1, l2, accu) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => accu
+  | (list{a1, ...l1}, list{a2, ...l2}) => f(a1, a2, fold_right2(f, l1, l2, accu))
+  | (_, _) => invalid_arg("List.fold_right2")
+  }
+
+let rec for_all = (p, param) =>
+  switch param {
+  | list{} => true
+  | list{a, ...l} => p(a) && for_all(p, l)
+  }
+
+let rec exists = (p, param) =>
+  switch param {
+  | list{} => false
+  | list{a, ...l} => p(a) || exists(p, l)
+  }
+
+let rec for_all2 = (p, l1, l2) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => true
+  | (list{a1, ...l1}, list{a2, ...l2}) => p(a1, a2) && for_all2(p, l1, l2)
+  | (_, _) => invalid_arg("List.for_all2")
+  }
+
+let rec exists2 = (p, l1, l2) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => false
+  | (list{a1, ...l1}, list{a2, ...l2}) => p(a1, a2) || exists2(p, l1, l2)
+  | (_, _) => invalid_arg("List.exists2")
+  }
+
+let rec mem = (x, param) =>
+  switch param {
+  | list{} => false
+  | list{a, ...l} => compare(a, x) == 0 || mem(x, l)
+  }
+
+let rec memq = (x, param) =>
+  switch param {
+  | list{} => false
+  | list{a, ...l} => a === x || memq(x, l)
+  }
+
+let rec assoc = (x, param) =>
+  switch param {
+  | list{} => raise(Not_found)
+  | list{(a, b), ...l} =>
+    if compare(a, x) == 0 {
+      b
+    } else {
+      assoc(x, l)
+    }
+  }
+
+let rec assoc_opt = (x, param) =>
+  switch param {
+  | list{} => None
+  | list{(a, b), ...l} =>
+    if compare(a, x) == 0 {
+      Some(b)
+    } else {
+      assoc_opt(x, l)
+    }
+  }
+
+let rec assq = (x, param) =>
+  switch param {
+  | list{} => raise(Not_found)
+  | list{(a, b), ...l} =>
+    if a === x {
+      b
+    } else {
+      assq(x, l)
+    }
+  }
+
+let rec assq_opt = (x, param) =>
+  switch param {
+  | list{} => None
+  | list{(a, b), ...l} =>
+    if a === x {
+      Some(b)
+    } else {
+      assq_opt(x, l)
+    }
+  }
+
+let rec mem_assoc = (x, param) =>
+  switch param {
+  | list{} => false
+  | list{(a, _), ...l} => compare(a, x) == 0 || mem_assoc(x, l)
+  }
+
+let rec mem_assq = (x, param) =>
+  switch param {
+  | list{} => false
+  | list{(a, _), ...l} => a === x || mem_assq(x, l)
+  }
+
+let rec remove_assoc = (x, param) =>
+  switch param {
+  | list{} => list{}
+  | list{(a, _) as pair, ...l} =>
+    if compare(a, x) == 0 {
+      l
+    } else {
+      list{pair, ...remove_assoc(x, l)}
+    }
+  }
+
+let rec remove_assq = (x, param) =>
+  switch param {
+  | list{} => list{}
+  | list{(a, _) as pair, ...l} =>
+    if a === x {
+      l
+    } else {
+      list{pair, ...remove_assq(x, l)}
+    }
+  }
+
+let rec find = (p, param) =>
+  switch param {
+  | list{} => raise(Not_found)
+  | list{x, ...l} =>
+    if p(x) {
+      x
+    } else {
+      find(p, l)
+    }
+  }
+
+let rec find_opt = (p, param) =>
+  switch param {
+  | list{} => None
+  | list{x, ...l} =>
+    if p(x) {
+      Some(x)
+    } else {
+      find_opt(p, l)
+    }
+  }
+
+let find_all = (p, l) => {
+  let rec find = (accu, param) =>
+    switch param {
+    | list{} => rev(accu)
+    | list{x, ...l} =>
+      if p(x) {
+        find(list{x, ...accu}, l)
+      } else {
+        find(accu, l)
+      }
+    }
+  find(list{}, l)
+}
+
+let filter = find_all
+
+let partition = (p, l) => {
+  let rec part = (yes, no, param) =>
+    switch param {
+    | list{} => (rev(yes), rev(no))
+    | list{x, ...l} =>
+      if p(x) {
+        part(list{x, ...yes}, no, l)
+      } else {
+        part(yes, list{x, ...no}, l)
+      }
+    }
+  part(list{}, list{}, l)
+}
+
+let rec split = param =>
+  switch param {
+  | list{} => (list{}, list{})
+  | list{(x, y), ...l} =>
+    let (rx, ry) = split(l)
+    (list{x, ...rx}, list{y, ...ry})
+  }
+
+let rec combine = (l1, l2) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => list{}
+  | (list{a1, ...l1}, list{a2, ...l2}) => list{(a1, a2), ...combine(l1, l2)}
+  | (_, _) => invalid_arg("List.combine")
+  }
+
+/* sorting */
+
+let rec merge = (cmp, l1, l2) =>
+  switch (l1, l2) {
+  | (list{}, l2) => l2
+  | (l1, list{}) => l1
+  | (list{h1, ...t1}, list{h2, ...t2}) =>
+    if cmp(h1, h2) <= 0 {
+      list{h1, ...merge(cmp, t1, l2)}
+    } else {
+      list{h2, ...merge(cmp, l1, t2)}
+    }
+  }
+
+let rec chop = (k, l) =>
+  if k == 0 {
+    l
+  } else {
+    switch l {
+    | list{_, ...t} => chop(k - 1, t)
+    | _ => assert(false)
+    }
+  }
+
+let stable_sort = (cmp, l) => {
+  let rec rev_merge = (l1, l2, accu) =>
+    switch (l1, l2) {
+    | (list{}, l2) => rev_append(l2, accu)
+    | (l1, list{}) => rev_append(l1, accu)
+    | (list{h1, ...t1}, list{h2, ...t2}) =>
+      if cmp(h1, h2) <= 0 {
+        rev_merge(t1, l2, list{h1, ...accu})
+      } else {
+        rev_merge(l1, t2, list{h2, ...accu})
+      }
+    }
+
+  let rec rev_merge_rev = (l1, l2, accu) =>
+    switch (l1, l2) {
+    | (list{}, l2) => rev_append(l2, accu)
+    | (l1, list{}) => rev_append(l1, accu)
+    | (list{h1, ...t1}, list{h2, ...t2}) =>
+      if cmp(h1, h2) > 0 {
+        rev_merge_rev(t1, l2, list{h1, ...accu})
+      } else {
+        rev_merge_rev(l1, t2, list{h2, ...accu})
+      }
+    }
+
+  let rec sort = (n, l) =>
+    switch (n, l) {
+    | (2, list{x1, x2, ..._}) =>
+      if cmp(x1, x2) <= 0 {
+        list{x1, x2}
+      } else {
+        list{x2, x1}
+      }
+    | (3, list{x1, x2, x3, ..._}) =>
+      if cmp(x1, x2) <= 0 {
+        if cmp(x2, x3) <= 0 {
+          list{x1, x2, x3}
+        } else if cmp(x1, x3) <= 0 {
+          list{x1, x3, x2}
+        } else {
+          list{x3, x1, x2}
+        }
+      } else if cmp(x1, x3) <= 0 {
+        list{x2, x1, x3}
+      } else if cmp(x2, x3) <= 0 {
+        list{x2, x3, x1}
+      } else {
+        list{x3, x2, x1}
+      }
+    | (n, l) =>
+      let n1 = asr(n, 1)
+      let n2 = n - n1
+      let l2 = chop(n1, l)
+      let s1 = rev_sort(n1, l)
+      let s2 = rev_sort(n2, l2)
+      rev_merge_rev(s1, s2, list{})
+    }
+  and rev_sort = (n, l) =>
+    switch (n, l) {
+    | (2, list{x1, x2, ..._}) =>
+      if cmp(x1, x2) > 0 {
+        list{x1, x2}
+      } else {
+        list{x2, x1}
+      }
+    | (3, list{x1, x2, x3, ..._}) =>
+      if cmp(x1, x2) > 0 {
+        if cmp(x2, x3) > 0 {
+          list{x1, x2, x3}
+        } else if cmp(x1, x3) > 0 {
+          list{x1, x3, x2}
+        } else {
+          list{x3, x1, x2}
+        }
+      } else if cmp(x1, x3) > 0 {
+        list{x2, x1, x3}
+      } else if cmp(x2, x3) > 0 {
+        list{x2, x3, x1}
+      } else {
+        list{x3, x2, x1}
+      }
+    | (n, l) =>
+      let n1 = asr(n, 1)
+      let n2 = n - n1
+      let l2 = chop(n1, l)
+      let s1 = sort(n1, l)
+      let s2 = sort(n2, l2)
+      rev_merge(s1, s2, list{})
+    }
+
+  let len = length(l)
+  if len < 2 {
+    l
+  } else {
+    sort(len, l)
+  }
+}
+
+let sort = stable_sort
+let fast_sort = stable_sort
+
+/* Note: on a list of length between about 100000 (depending on the minor
+  heap size and the type of the list) and Sys.max_array_size, it is
+  actually faster to use the following, but it might also use more memory
+  because the argument list cannot be deallocated incrementally.
+
+  Also, there seems to be a bug in this code or in the
+  implementation of obj_truncate.
+
+external obj_truncate : 'a array -> int -> unit = "caml_obj_truncate"
+
+let array_to_list_in_place a =
+  let l = Array.length a in
+  let rec loop accu n p =
+    if p <= 0 then accu else begin
+      if p = n then begin
+        obj_truncate a p;
+        loop (a.(p-1) :: accu) (n-1000) (p-1)
+      end else begin
+        loop (a.(p-1) :: accu) n (p-1)
+      end
+    end
+  in
+  loop [] (l-1000) l
+
+
+let stable_sort cmp l =
+  let a = Array.of_list l in
+  Array.stable_sort cmp a;
+  array_to_list_in_place a
+
+*/
+
+/* sorting + removing duplicates */
+
+let sort_uniq = (cmp, l) => {
+  let rec rev_merge = (l1, l2, accu) =>
+    switch (l1, l2) {
+    | (list{}, l2) => rev_append(l2, accu)
+    | (l1, list{}) => rev_append(l1, accu)
+    | (list{h1, ...t1}, list{h2, ...t2}) =>
+      let c = cmp(h1, h2)
+      if c == 0 {
+        rev_merge(t1, t2, list{h1, ...accu})
+      } else if c < 0 {
+        rev_merge(t1, l2, list{h1, ...accu})
+      } else {
+        rev_merge(l1, t2, list{h2, ...accu})
+      }
+    }
+
+  let rec rev_merge_rev = (l1, l2, accu) =>
+    switch (l1, l2) {
+    | (list{}, l2) => rev_append(l2, accu)
+    | (l1, list{}) => rev_append(l1, accu)
+    | (list{h1, ...t1}, list{h2, ...t2}) =>
+      let c = cmp(h1, h2)
+      if c == 0 {
+        rev_merge_rev(t1, t2, list{h1, ...accu})
+      } else if c > 0 {
+        rev_merge_rev(t1, l2, list{h1, ...accu})
+      } else {
+        rev_merge_rev(l1, t2, list{h2, ...accu})
+      }
+    }
+
+  let rec sort = (n, l) =>
+    switch (n, l) {
+    | (2, list{x1, x2, ..._}) =>
+      let c = cmp(x1, x2)
+      if c == 0 {
+        list{x1}
+      } else if c < 0 {
+        list{x1, x2}
+      } else {
+        list{x2, x1}
+      }
+    | (3, list{x1, x2, x3, ..._}) =>
+      let c = cmp(x1, x2)
+      if c == 0 {
+        let c = cmp(x2, x3)
+        if c == 0 {
+          list{x2}
+        } else if c < 0 {
+          list{x2, x3}
+        } else {
+          list{x3, x2}
+        }
+      } else if c < 0 {
+        let c = cmp(x2, x3)
+        if c == 0 {
+          list{x1, x2}
+        } else if c < 0 {
+          list{x1, x2, x3}
+        } else {
+          let c = cmp(x1, x3)
+          if c == 0 {
+            list{x1, x2}
+          } else if c < 0 {
+            list{x1, x3, x2}
+          } else {
+            list{x3, x1, x2}
+          }
+        }
+      } else {
+        let c = cmp(x1, x3)
+        if c == 0 {
+          list{x2, x1}
+        } else if c < 0 {
+          list{x2, x1, x3}
+        } else {
+          let c = cmp(x2, x3)
+          if c == 0 {
+            list{x2, x1}
+          } else if c < 0 {
+            list{x2, x3, x1}
+          } else {
+            list{x3, x2, x1}
+          }
+        }
+      }
+    | (n, l) =>
+      let n1 = asr(n, 1)
+      let n2 = n - n1
+      let l2 = chop(n1, l)
+      let s1 = rev_sort(n1, l)
+      let s2 = rev_sort(n2, l2)
+      rev_merge_rev(s1, s2, list{})
+    }
+  and rev_sort = (n, l) =>
+    switch (n, l) {
+    | (2, list{x1, x2, ..._}) =>
+      let c = cmp(x1, x2)
+      if c == 0 {
+        list{x1}
+      } else if c > 0 {
+        list{x1, x2}
+      } else {
+        list{x2, x1}
+      }
+    | (3, list{x1, x2, x3, ..._}) =>
+      let c = cmp(x1, x2)
+      if c == 0 {
+        let c = cmp(x2, x3)
+        if c == 0 {
+          list{x2}
+        } else if c > 0 {
+          list{x2, x3}
+        } else {
+          list{x3, x2}
+        }
+      } else if c > 0 {
+        let c = cmp(x2, x3)
+        if c == 0 {
+          list{x1, x2}
+        } else if c > 0 {
+          list{x1, x2, x3}
+        } else {
+          let c = cmp(x1, x3)
+          if c == 0 {
+            list{x1, x2}
+          } else if c > 0 {
+            list{x1, x3, x2}
+          } else {
+            list{x3, x1, x2}
+          }
+        }
+      } else {
+        let c = cmp(x1, x3)
+        if c == 0 {
+          list{x2, x1}
+        } else if c > 0 {
+          list{x2, x1, x3}
+        } else {
+          let c = cmp(x2, x3)
+          if c == 0 {
+            list{x2, x1}
+          } else if c > 0 {
+            list{x2, x3, x1}
+          } else {
+            list{x3, x2, x1}
+          }
+        }
+      }
+    | (n, l) =>
+      let n1 = asr(n, 1)
+      let n2 = n - n1
+      let l2 = chop(n1, l)
+      let s1 = sort(n1, l)
+      let s2 = sort(n2, l2)
+      rev_merge(s1, s2, list{})
+    }
+
+  let len = length(l)
+  if len < 2 {
+    l
+  } else {
+    sort(len, l)
+  }
+}
+
+let rec compare_lengths = (l1, l2) =>
+  switch (l1, l2) {
+  | (list{}, list{}) => 0
+  | (list{}, _) => -1
+  | (_, list{}) => 1
+  | (list{_, ...l1}, list{_, ...l2}) => compare_lengths(l1, l2)
+  }
+
+let rec compare_length_with = (l, n) =>
+  switch l {
+  | list{} =>
+    if n == 0 {
+      0
+    } else if n > 0 {
+      -1
+    } else {
+      1
+    }
+  | list{_, ...l} =>
+    if n <= 0 {
+      1
+    } else {
+      compare_length_with(l, n - 1)
+    }
+  }
diff --git a/tests/tests/src/ocaml_compat/Ocaml_List.resi b/tests/tests/src/ocaml_compat/Ocaml_List.resi
new file mode 100644
index 0000000000..1fdfd31f0c
--- /dev/null
+++ b/tests/tests/src/ocaml_compat/Ocaml_List.resi
@@ -0,0 +1,365 @@
+// FIXME:
+//   This exists for compatibility reason.
+//   Move this into Pervasives or Core
+
+// Below is all deprecated and should be removed in v13
+
+@deprecated("Use Core instead. This will be removed in v13")
+type t<'a> = list<'a>
+
+/** Return the length (number of elements) of the given list. */
+@deprecated("Use Core instead. This will be removed in v13")
+let length: list<'a> => int
+
+/** Compare the lengths of two lists. [compare_lengths l1 l2] is
+   equivalent to [compare (length l1) (length l2)], except that
+   the computation stops after itering on the shortest list.
+   @since 4.05.0
+ */
+@deprecated("Use Core instead. This will be removed in v13")
+let compare_lengths: (list<'a>, list<'b>) => int
+
+/** Compare the length of a list to an integer. [compare_length_with l n] is
+   equivalent to [compare (length l) n], except that
+   the computation stops after at most [n] iterations on the list.
+   @since 4.05.0
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let compare_length_with: (list<'a>, int) => int
+
+/** [cons x xs] is [x :: xs]
+    @since 4.03.0
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let cons: ('a, list<'a>) => list<'a>
+
+/** Return the first element of the given list. Raise
+   [Failure "hd"] if the list is empty. */
+@deprecated("Use Core instead. This will be removed in v13")
+let hd: list<'a> => 'a
+
+/** Return the given list without its first element. Raise
+    [Failure "tl"] if the list is empty. */
+@deprecated("Use Core instead. This will be removed in v13")
+let tl: list<'a> => list<'a>
+
+/** Return the [n]-th element of the given list.
+   The first element (head of the list) is at position 0.
+   Raise [Failure "nth"] if the list is too short.
+   Raise [Invalid_argument "List.nth"] if [n] is negative. */
+@deprecated("Use Core instead. This will be removed in v13")
+let nth: (list<'a>, int) => 'a
+
+/** Return the [n]-th element of the given list.
+    The first element (head of the list) is at position 0.
+    Return [None] if the list is too short.
+    Raise [Invalid_argument "List.nth"] if [n] is negative.
+    @since 4.05
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let nth_opt: (list<'a>, int) => option<'a>
+
+/** List reversal. */
+@deprecated("Use Core instead. This will be removed in v13")
+let rev: list<'a> => list<'a>
+
+/** [List.init len f] is [f 0; f 1; ...; f (len-1)], evaluated left to right.
+
+    @raise Invalid_argument if len < 0.
+    @since 4.06.0
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let init: (int, int => 'a) => list<'a>
+
+/** Concatenate two lists.  Same as the infix operator [@].
+   Not tail-recursive (length of the first argument).  */
+@deprecated("Use Core instead. This will be removed in v13")
+let append: (list<'a>, list<'a>) => list<'a>
+
+/** [List.rev_append l1 l2] reverses [l1] and concatenates it to [l2].
+   This is equivalent to {!List.rev}[ l1 @ l2], but [rev_append] is
+   tail-recursive and more efficient. */
+@deprecated("Use Core instead. This will be removed in v13")
+let rev_append: (list<'a>, list<'a>) => list<'a>
+
+/** Concatenate a list of lists.  The elements of the argument are all
+   concatenated together (in the same order) to give the result.
+   Not tail-recursive
+   (length of the argument + length of the longest sub-list). */
+@deprecated("Use Core instead. This will be removed in v13")
+let concat: list<list<'a>> => list<'a>
+
+/** An alias for [concat]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let flatten: list<list<'a>> => list<'a>
+
+/* {1 Iterators} */
+
+/** [List.iter f [a1; ...; an]] applies function [f] in turn to
+   [a1; ...; an]. It is equivalent to
+   [begin f a1; f a2; ...; f an; () end]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let iter: ('a => unit, list<'a>) => unit
+
+/** Same as {!List.iter}, but the function is applied to the index of
+   the element as first argument (counting from 0), and the element
+   itself as second argument.
+   @since 4.00.0
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let iteri: ((int, 'a) => unit, list<'a>) => unit
+
+/** [List.map f [a1; ...; an]] applies function [f] to [a1, ..., an],
+   and builds the list [[f a1; ...; f an]]
+   with the results returned by [f].  Not tail-recursive. */
+@deprecated("Use Core instead. This will be removed in v13")
+let map: ('a => 'b, list<'a>) => list<'b>
+
+/** Same as {!List.map}, but the function is applied to the index of
+   the element as first argument (counting from 0), and the element
+   itself as second argument.  Not tail-recursive.
+   @since 4.00.0
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let mapi: ((int, 'a) => 'b, list<'a>) => list<'b>
+
+/** [List.rev_map f l] gives the same result as
+   {!List.rev}[ (]{!List.map}[ f l)], but is tail-recursive and
+   more efficient. */
+@deprecated("Use Core instead. This will be removed in v13")
+let rev_map: ('a => 'b, list<'a>) => list<'b>
+
+/** [List.fold_left f a [b1; ...; bn]] is
+   [f (... (f (f a b1) b2) ...) bn]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let fold_left: (('a, 'b) => 'a, 'a, list<'b>) => 'a
+
+/** [List.fold_right f [a1; ...; an] b] is
+   [f a1 (f a2 (... (f an b) ...))].  Not tail-recursive. */
+@deprecated("Use Core instead. This will be removed in v13")
+let fold_right: (('a, 'b) => 'b, list<'a>, 'b) => 'b
+
+/* {1 Iterators on two lists} */
+
+/** [List.iter2 f [a1; ...; an] [b1; ...; bn]] calls in turn
+   [f a1 b1; ...; f an bn].
+   Raise [Invalid_argument] if the two lists are determined
+   to have different lengths. */
+@deprecated("Use Core instead. This will be removed in v13")
+let iter2: (('a, 'b) => unit, list<'a>, list<'b>) => unit
+
+/** [List.map2 f [a1; ...; an] [b1; ...; bn]] is
+   [[f a1 b1; ...; f an bn]].
+   Raise [Invalid_argument] if the two lists are determined
+   to have different lengths.  Not tail-recursive. */
+@deprecated("Use Core instead. This will be removed in v13")
+let map2: (('a, 'b) => 'c, list<'a>, list<'b>) => list<'c>
+
+/** [List.rev_map2 f l1 l2] gives the same result as
+   {!List.rev}[ (]{!List.map2}[ f l1 l2)], but is tail-recursive and
+   more efficient. */
+@deprecated("Use Core instead. This will be removed in v13")
+let rev_map2: (('a, 'b) => 'c, list<'a>, list<'b>) => list<'c>
+
+/** [List.fold_left2 f a [b1; ...; bn] [c1; ...; cn]] is
+   [f (... (f (f a b1 c1) b2 c2) ...) bn cn].
+   Raise [Invalid_argument] if the two lists are determined
+   to have different lengths. */
+@deprecated("Use Core instead. This will be removed in v13")
+let fold_left2: (('a, 'b, 'c) => 'a, 'a, list<'b>, list<'c>) => 'a
+
+/** [List.fold_right2 f [a1; ...; an] [b1; ...; bn] c] is
+   [f a1 b1 (f a2 b2 (... (f an bn c) ...))].
+   Raise [Invalid_argument] if the two lists are determined
+   to have different lengths.  Not tail-recursive. */
+@deprecated("Use Core instead. This will be removed in v13")
+let fold_right2: (('a, 'b, 'c) => 'c, list<'a>, list<'b>, 'c) => 'c
+
+/* {1 List scanning} */
+
+/** [for_all p [a1; ...; an]] checks if all elements of the list
+   satisfy the predicate [p]. That is, it returns
+   [(p a1) && (p a2) && ... && (p an)]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let for_all: ('a => bool, list<'a>) => bool
+
+/** [exists p [a1; ...; an]] checks if at least one element of
+   the list satisfies the predicate [p]. That is, it returns
+   [(p a1) || (p a2) || ... || (p an)]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let exists: ('a => bool, list<'a>) => bool
+
+/** Same as {!List.for_all}, but for a two-argument predicate.
+   Raise [Invalid_argument] if the two lists are determined
+   to have different lengths. */
+@deprecated("Use Core instead. This will be removed in v13")
+let for_all2: (('a, 'b) => bool, list<'a>, list<'b>) => bool
+
+/** Same as {!List.exists}, but for a two-argument predicate.
+   Raise [Invalid_argument] if the two lists are determined
+   to have different lengths. */
+@deprecated("Use Core instead. This will be removed in v13")
+let exists2: (('a, 'b) => bool, list<'a>, list<'b>) => bool
+
+/** [mem a l] is true if and only if [a] is equal
+   to an element of [l]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let mem: ('a, list<'a>) => bool
+
+/** Same as {!List.mem}, but uses physical equality instead of structural
+   equality to compare list elements. */
+@deprecated("Use Core instead. This will be removed in v13")
+let memq: ('a, list<'a>) => bool
+
+/* {1 List searching} */
+
+/** [find p l] returns the first element of the list [l]
+   that satisfies the predicate [p].
+   Raise [Not_found] if there is no value that satisfies [p] in the
+   list [l]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let find: ('a => bool, list<'a>) => 'a
+
+/** [find_opt p l] returns the first element of the list [l] that
+    satisfies the predicate [p], or [None] if there is no value that
+    satisfies [p] in the list [l].
+    @since 4.05 */
+@deprecated("Use Core instead. This will be removed in v13")
+let find_opt: ('a => bool, list<'a>) => option<'a>
+
+/** [filter p l] returns all the elements of the list [l]
+   that satisfy the predicate [p].  The order of the elements
+   in the input list is preserved.  */
+@deprecated("Use Core instead. This will be removed in v13")
+let filter: ('a => bool, list<'a>) => list<'a>
+
+/** [find_all] is another name for {!List.filter}. */
+let find_all: ('a => bool, list<'a>) => list<'a>
+
+/** [partition p l] returns a pair of lists [(l1, l2)], where
+   [l1] is the list of all the elements of [l] that
+   satisfy the predicate [p], and [l2] is the list of all the
+   elements of [l] that do not satisfy [p].
+   The order of the elements in the input list is preserved. */
+@deprecated("Use Core instead. This will be removed in v13")
+let partition: ('a => bool, list<'a>) => (list<'a>, list<'a>)
+
+/* {1 Association lists} */
+
+/** [assoc a l] returns the value associated with key [a] in the list of
+   pairs [l]. That is,
+   [assoc a [ ...; (a,b); ...] = b]
+   if [(a,b)] is the leftmost binding of [a] in list [l].
+   Raise [Not_found] if there is no value associated with [a] in the
+   list [l]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let assoc: ('a, list<('a, 'b)>) => 'b
+
+/** [assoc_opt a l] returns the value associated with key [a] in the list of
+   pairs [l]. That is,
+   [assoc_opt a [ ...; (a,b); ...] = b]
+   if [(a,b)] is the leftmost binding of [a] in list [l].
+   Returns [None] if there is no value associated with [a] in the
+   list [l].
+   @since 4.05 */
+@deprecated("Use Core instead. This will be removed in v13")
+let assoc_opt: ('a, list<('a, 'b)>) => option<'b>
+
+/** Same as {!List.assoc}, but uses physical equality instead of structural
+   equality to compare keys. */
+@deprecated("Use Core instead. This will be removed in v13")
+let assq: ('a, list<('a, 'b)>) => 'b
+
+/** Same as {!List.assoc_opt}, but uses physical equality instead of structural
+    equality to compare keys.
+    @since 4.05 */
+@deprecated("Use Core instead. This will be removed in v13")
+let assq_opt: ('a, list<('a, 'b)>) => option<'b>
+
+/** Same as {!List.assoc}, but simply return true if a binding exists,
+   and false if no bindings exist for the given key. */
+@deprecated("Use Core instead. This will be removed in v13")
+let mem_assoc: ('a, list<('a, 'b)>) => bool
+
+/** Same as {!List.mem_assoc}, but uses physical equality instead of
+   structural equality to compare keys. */
+@deprecated("Use Core instead. This will be removed in v13")
+let mem_assq: ('a, list<('a, 'b)>) => bool
+
+/** [remove_assoc a l] returns the list of
+   pairs [l] without the first pair with key [a], if any.
+   Not tail-recursive. */
+@deprecated("Use Core instead. This will be removed in v13")
+let remove_assoc: ('a, list<('a, 'b)>) => list<('a, 'b)>
+
+/** Same as {!List.remove_assoc}, but uses physical equality instead
+   of structural equality to compare keys.  Not tail-recursive. */
+@deprecated("Use Core instead. This will be removed in v13")
+let remove_assq: ('a, list<('a, 'b)>) => list<('a, 'b)>
+
+/* {1 Lists of pairs} */
+
+/** Transform a list of pairs into a pair of lists:
+   [split [(a1,b1); ...; (an,bn)]] is [([a1; ...; an], [b1; ...; bn])].
+   Not tail-recursive.
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let split: list<('a, 'b)> => (list<'a>, list<'b>)
+
+/** Transform a pair of lists into a list of pairs:
+   [combine [a1; ...; an] [b1; ...; bn]] is
+   [[(a1,b1); ...; (an,bn)]].
+   Raise [Invalid_argument] if the two lists
+   have different lengths.  Not tail-recursive. */
+@deprecated("Use Core instead. This will be removed in v13")
+let combine: (list<'a>, list<'b>) => list<('a, 'b)>
+
+/* {1 Sorting} */
+
+/** Sort a list in increasing order according to a comparison
+   function.  The comparison function must return 0 if its arguments
+   compare as equal, a positive integer if the first is greater,
+   and a negative integer if the first is smaller (see Array.sort for
+   a complete specification).  For example,
+   {!Pervasives.compare} is a suitable comparison function.
+   The resulting list is sorted in increasing order.
+   [List.sort] is guaranteed to run in constant heap space
+   (in addition to the size of the result list) and logarithmic
+   stack space.
+
+   The current implementation uses Merge Sort. It runs in constant
+   heap space and logarithmic stack space.
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let sort: (('a, 'a) => int, list<'a>) => list<'a>
+
+/** Same as {!List.sort}, but the sorting algorithm is guaranteed to
+   be stable (i.e. elements that compare equal are kept in their
+   original order) .
+
+   The current implementation uses Merge Sort. It runs in constant
+   heap space and logarithmic stack space.
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let stable_sort: (('a, 'a) => int, list<'a>) => list<'a>
+
+/** Same as {!List.sort} or {!List.stable_sort}, whichever is faster
+    on typical input. */
+@deprecated("Use Core instead. This will be removed in v13")
+let fast_sort: (('a, 'a) => int, list<'a>) => list<'a>
+
+/** Same as {!List.sort}, but also remove duplicates.
+    @since 4.02.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let sort_uniq: (('a, 'a) => int, list<'a>) => list<'a>
+
+/** Merge two lists:
+    Assuming that [l1] and [l2] are sorted according to the
+    comparison function [cmp], [merge cmp l1 l2] will return a
+    sorted list containing all the elements of [l1] and [l2].
+    If several elements compare equal, the elements of [l1] will be
+    before the elements of [l2].
+    Not tail-recursive (sum of the lengths of the arguments).
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let merge: (('a, 'a) => int, list<'a>, list<'a>) => list<'a>
diff --git a/tests/tests/src/ocaml_compat/Ocaml_String.js b/tests/tests/src/ocaml_compat/Ocaml_String.js
new file mode 100644
index 0000000000..8e38ceb32d
--- /dev/null
+++ b/tests/tests/src/ocaml_compat/Ocaml_String.js
@@ -0,0 +1,303 @@
+// Generated by ReScript, PLEASE EDIT WITH CARE
+'use strict';
+
+let Char = require("rescript/lib/js/Char.js");
+let Pervasives = require("rescript/lib/js/Pervasives.js");
+let Ocaml_Array = require("./Ocaml_Array.js");
+let Primitive_exceptions = require("rescript/lib/js/Primitive_exceptions.js");
+
+function apply1(f, bytes) {
+  if (bytes.length === 0) {
+    return bytes;
+  }
+  let r = bytes.slice();
+  r[0] = f(bytes[0]);
+  return r;
+}
+
+function concat(sep, xs) {
+  return Ocaml_Array.of_list(xs).join(sep);
+}
+
+function bos(str) {
+  return Ocaml_Array.map(str => str.codePointAt(0), Array.from(str));
+}
+
+function make(len, ch) {
+  return String.fromCodePoint(ch).repeat(len);
+}
+
+function init(len, f) {
+  return Ocaml_Array.init(len, i => String.fromCodePoint(f(i))).join("");
+}
+
+function sub(s, ofs, len) {
+  return String.fromCodePoint(...Ocaml_Array.sub(bos(s), ofs, len));
+}
+
+function iter(f, s) {
+  for (let i = 0, i_finish = s.length; i < i_finish; ++i) {
+    f(s.codePointAt(i));
+  }
+}
+
+function iteri(f, s) {
+  for (let i = 0, i_finish = s.length; i < i_finish; ++i) {
+    f(i, s.codePointAt(i));
+  }
+}
+
+function map(f, s) {
+  return String.fromCodePoint(...Ocaml_Array.map(f, bos(s)));
+}
+
+function mapi(f, s) {
+  return String.fromCodePoint(...Ocaml_Array.mapi(f, bos(s)));
+}
+
+function escaped(s) {
+  let needs_escape = _i => {
+    while (true) {
+      let i = _i;
+      if (i >= s.length) {
+        return false;
+      }
+      let match = s.codePointAt(i);
+      if (match < 32) {
+        return true;
+      }
+      if (match > 92 || match < 34) {
+        if (match >= 127) {
+          return true;
+        }
+        _i = i + 1 | 0;
+        continue;
+      }
+      if (match > 91 || match < 35) {
+        return true;
+      }
+      _i = i + 1 | 0;
+      continue;
+    };
+  };
+  if (!needs_escape(0)) {
+    return s;
+  }
+  let bytes = bos(s);
+  return Ocaml_Array.map(Char.escaped, bytes).join("");
+}
+
+function index_rec(s, lim, _i, c) {
+  while (true) {
+    let i = _i;
+    if (i >= lim) {
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
+    }
+    if (s.codePointAt(i) === c) {
+      return i;
+    }
+    _i = i + 1 | 0;
+    continue;
+  };
+}
+
+function index(s, c) {
+  return index_rec(s, s.length, 0, c);
+}
+
+function index_rec_opt(s, lim, _i, c) {
+  while (true) {
+    let i = _i;
+    if (i >= lim) {
+      return;
+    }
+    if (s.codePointAt(i) === c) {
+      return i;
+    }
+    _i = i + 1 | 0;
+    continue;
+  };
+}
+
+function index_opt(s, c) {
+  return index_rec_opt(s, s.length, 0, c);
+}
+
+function index_from(s, i, c) {
+  let l = s.length;
+  if (i < 0 || i > l) {
+    return Pervasives.invalid_arg("String.index_from / Bytes.index_from");
+  } else {
+    return index_rec(s, l, i, c);
+  }
+}
+
+function index_from_opt(s, i, c) {
+  let l = s.length;
+  if (i < 0 || i > l) {
+    return Pervasives.invalid_arg("String.index_from_opt / Bytes.index_from_opt");
+  } else {
+    return index_rec_opt(s, l, i, c);
+  }
+}
+
+function rindex_rec(s, _i, c) {
+  while (true) {
+    let i = _i;
+    if (i < 0) {
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
+    }
+    if (s.codePointAt(i) === c) {
+      return i;
+    }
+    _i = i - 1 | 0;
+    continue;
+  };
+}
+
+function rindex(s, c) {
+  return rindex_rec(s, s.length - 1 | 0, c);
+}
+
+function rindex_from(s, i, c) {
+  if (i < -1 || i >= s.length) {
+    return Pervasives.invalid_arg("String.rindex_from / Bytes.rindex_from");
+  } else {
+    return rindex_rec(s, i, c);
+  }
+}
+
+function rindex_rec_opt(s, _i, c) {
+  while (true) {
+    let i = _i;
+    if (i < 0) {
+      return;
+    }
+    if (s.codePointAt(i) === c) {
+      return i;
+    }
+    _i = i - 1 | 0;
+    continue;
+  };
+}
+
+function rindex_opt(s, c) {
+  return rindex_rec_opt(s, s.length - 1 | 0, c);
+}
+
+function rindex_from_opt(s, i, c) {
+  if (i < -1 || i >= s.length) {
+    return Pervasives.invalid_arg("String.rindex_from_opt / Bytes.rindex_from_opt");
+  } else {
+    return rindex_rec_opt(s, i, c);
+  }
+}
+
+function contains_from(s, i, c) {
+  let l = s.length;
+  if (i < 0 || i > l) {
+    return Pervasives.invalid_arg("String.contains_from / Bytes.contains_from");
+  }
+  try {
+    index_rec(s, l, i, c);
+    return true;
+  } catch (raw_exn) {
+    let exn = Primitive_exceptions.internalToException(raw_exn);
+    if (exn.RE_EXN_ID === "Not_found") {
+      return false;
+    }
+    throw exn;
+  }
+}
+
+function contains(s, c) {
+  return contains_from(s, 0, c);
+}
+
+function rcontains_from(s, i, c) {
+  if (i < 0 || i >= s.length) {
+    return Pervasives.invalid_arg("String.rcontains_from / Bytes.rcontains_from");
+  }
+  try {
+    rindex_rec(s, i, c);
+    return true;
+  } catch (raw_exn) {
+    let exn = Primitive_exceptions.internalToException(raw_exn);
+    if (exn.RE_EXN_ID === "Not_found") {
+      return false;
+    }
+    throw exn;
+  }
+}
+
+function uppercase_ascii(s) {
+  let bytes = bos(s);
+  return String.fromCodePoint(...Ocaml_Array.map(Char.uppercase_ascii, bytes));
+}
+
+function lowercase_ascii(s) {
+  let bytes = bos(s);
+  return String.fromCodePoint(...Ocaml_Array.map(Char.lowercase_ascii, bytes));
+}
+
+function capitalize_ascii(s) {
+  let bytes = bos(s);
+  return String.fromCodePoint(...apply1(Char.uppercase_ascii, bytes));
+}
+
+function uncapitalize_ascii(s) {
+  let bytes = bos(s);
+  return String.fromCodePoint(...apply1(Char.lowercase_ascii, bytes));
+}
+
+function split_on_char(sep, s) {
+  let r = /* [] */0;
+  let j = s.length;
+  for (let i = s.length - 1 | 0; i >= 0; --i) {
+    if (s.codePointAt(i) === sep) {
+      r = {
+        hd: sub(s, i + 1 | 0, (j - i | 0) - 1 | 0),
+        tl: r
+      };
+      j = i;
+    }
+    
+  }
+  return {
+    hd: sub(s, 0, j),
+    tl: r
+  };
+}
+
+exports.make = make;
+exports.init = init;
+exports.sub = sub;
+exports.concat = concat;
+exports.iter = iter;
+exports.iteri = iteri;
+exports.map = map;
+exports.mapi = mapi;
+exports.escaped = escaped;
+exports.index = index;
+exports.index_opt = index_opt;
+exports.rindex = rindex;
+exports.rindex_opt = rindex_opt;
+exports.index_from = index_from;
+exports.index_from_opt = index_from_opt;
+exports.rindex_from = rindex_from;
+exports.rindex_from_opt = rindex_from_opt;
+exports.contains = contains;
+exports.contains_from = contains_from;
+exports.rcontains_from = rcontains_from;
+exports.uppercase_ascii = uppercase_ascii;
+exports.lowercase_ascii = lowercase_ascii;
+exports.capitalize_ascii = capitalize_ascii;
+exports.uncapitalize_ascii = uncapitalize_ascii;
+exports.split_on_char = split_on_char;
+/* No side effect */
diff --git a/tests/tests/src/ocaml_compat/Ocaml_String.res b/tests/tests/src/ocaml_compat/Ocaml_String.res
new file mode 100644
index 0000000000..2c0f049e68
--- /dev/null
+++ b/tests/tests/src/ocaml_compat/Ocaml_String.res
@@ -0,0 +1,225 @@
+// FIXME:
+//   This exists for compatibility reason.
+//   Move this into Pervasives or Core
+
+// Below is all deprecated and should be removed in v13
+
+module Array = Ocaml_Array
+
+type t = string
+
+module B = {
+  include Array
+
+  let uppercase_ascii = bytes => map(Char.uppercase_ascii, bytes)
+  let lowercase_ascii = bytes => map(Char.lowercase_ascii, bytes)
+
+  let apply1 = (f, bytes) =>
+    if length(bytes) == 0 {
+      bytes
+    } else {
+      let r = copy(bytes)
+      unsafe_set(r, 0, f(unsafe_get(bytes, 0)))
+      r
+    }
+  let capitalize_ascii = bytes => apply1(Char.uppercase_ascii, bytes)
+  let uncapitalize_ascii = bytes => apply1(Char.lowercase_ascii, bytes)
+
+  let escaped = bytes => map(Char.escaped, bytes)
+}
+
+@send external join: (array<string>, string) => string = "join"
+
+let concat = (sep: string, xs: list<string>) => xs->Array.of_list->join(sep)
+
+external length: string => int = "%string_length"
+
+@send external get: (string, int) => char = "codePointAt"
+
+@send external unsafe_get: (string, int) => char = "codePointAt"
+
+@scope("Array") external bos: string => array<string> = "from"
+let bos = str => B.map(str => str->unsafe_get(0), str->bos)
+
+@scope("String") @variadic
+external bts: array<char> => string = "fromCodePoint"
+
+let make = (len, ch) => Primitive_string_extern.fromChar(ch)->Primitive_string_extern.repeat(len)
+
+let init = (len, f) => Array.init(len, i => Primitive_string_extern.fromChar(f(i)))->join("")
+
+let sub = (s, ofs, len) => bts(B.sub(bos(s), ofs, len))
+
+external compare: (t, t) => int = "%compare"
+
+external equal: (t, t) => bool = "%equal"
+
+let iter = (f, s) =>
+  for i in 0 to length(s) - 1 {
+    f(unsafe_get(s, i))
+  }
+
+let iteri = (f, s) =>
+  for i in 0 to length(s) - 1 {
+    f(i, unsafe_get(s, i))
+  }
+
+let map = (f, s) => bts(B.map(f, bos(s)))
+let mapi = (f, s) => bts(B.mapi(f, bos(s)))
+
+@send external trim: string => string = "trim"
+
+let escaped = s => {
+  let rec needs_escape = i =>
+    if i >= length(s) {
+      false
+    } else {
+      switch unsafe_get(s, i) {
+      | '"' | '\\' | '\n' | '\t' | '\r' | '\b' => true
+      | ' ' .. '~' => needs_escape(i + 1)
+      | _ => true
+      }
+    }
+
+  if needs_escape(0) {
+    join(B.escaped(bos(s)), "")
+  } else {
+    s
+  }
+}
+
+/* duplicated in bytes.ml */
+let rec index_rec = (s, lim, i, c) =>
+  if i >= lim {
+    raise(Not_found)
+  } else if unsafe_get(s, i) == c {
+    i
+  } else {
+    index_rec(s, lim, i + 1, c)
+  }
+
+/* duplicated in bytes.ml */
+let index = (s, c) => index_rec(s, length(s), 0, c)
+
+/* duplicated in bytes.ml */
+let rec index_rec_opt = (s, lim, i, c) =>
+  if i >= lim {
+    None
+  } else if unsafe_get(s, i) == c {
+    Some(i)
+  } else {
+    index_rec_opt(s, lim, i + 1, c)
+  }
+
+/* duplicated in bytes.ml */
+let index_opt = (s, c) => index_rec_opt(s, length(s), 0, c)
+
+/* duplicated in bytes.ml */
+let index_from = (s, i, c) => {
+  let l = length(s)
+  if i < 0 || i > l {
+    invalid_arg("String.index_from / Bytes.index_from")
+  } else {
+    index_rec(s, l, i, c)
+  }
+}
+
+/* duplicated in bytes.ml */
+let index_from_opt = (s, i, c) => {
+  let l = length(s)
+  if i < 0 || i > l {
+    invalid_arg("String.index_from_opt / Bytes.index_from_opt")
+  } else {
+    index_rec_opt(s, l, i, c)
+  }
+}
+
+/* duplicated in bytes.ml */
+let rec rindex_rec = (s, i, c) =>
+  if i < 0 {
+    raise(Not_found)
+  } else if unsafe_get(s, i) == c {
+    i
+  } else {
+    rindex_rec(s, i - 1, c)
+  }
+
+/* duplicated in bytes.ml */
+let rindex = (s, c) => rindex_rec(s, length(s) - 1, c)
+
+/* duplicated in bytes.ml */
+let rindex_from = (s, i, c) =>
+  if i < -1 || i >= length(s) {
+    invalid_arg("String.rindex_from / Bytes.rindex_from")
+  } else {
+    rindex_rec(s, i, c)
+  }
+
+/* duplicated in bytes.ml */
+let rec rindex_rec_opt = (s, i, c) =>
+  if i < 0 {
+    None
+  } else if unsafe_get(s, i) == c {
+    Some(i)
+  } else {
+    rindex_rec_opt(s, i - 1, c)
+  }
+
+/* duplicated in bytes.ml */
+let rindex_opt = (s, c) => rindex_rec_opt(s, length(s) - 1, c)
+
+/* duplicated in bytes.ml */
+let rindex_from_opt = (s, i, c) =>
+  if i < -1 || i >= length(s) {
+    invalid_arg("String.rindex_from_opt / Bytes.rindex_from_opt")
+  } else {
+    rindex_rec_opt(s, i, c)
+  }
+
+/* duplicated in bytes.ml */
+let contains_from = (s, i, c) => {
+  let l = length(s)
+  if i < 0 || i > l {
+    invalid_arg("String.contains_from / Bytes.contains_from")
+  } else {
+    try {
+      ignore(index_rec(s, l, i, c))
+      true
+    } catch {
+    | Not_found => false
+    }
+  }
+}
+
+/* duplicated in bytes.ml */
+let contains = (s, c) => contains_from(s, 0, c)
+
+/* duplicated in bytes.ml */
+let rcontains_from = (s, i, c) =>
+  if i < 0 || i >= length(s) {
+    invalid_arg("String.rcontains_from / Bytes.rcontains_from")
+  } else {
+    try {
+      ignore(rindex_rec(s, i, c))
+      true
+    } catch {
+    | Not_found => false
+    }
+  }
+
+let uppercase_ascii = s => bts(B.uppercase_ascii(bos(s)))
+let lowercase_ascii = s => bts(B.lowercase_ascii(bos(s)))
+let capitalize_ascii = s => bts(B.capitalize_ascii(bos(s)))
+let uncapitalize_ascii = s => bts(B.uncapitalize_ascii(bos(s)))
+
+let split_on_char = (sep, s) => {
+  let r = ref(list{})
+  let j = ref(length(s))
+  for i in length(s) - 1 downto 0 {
+    if unsafe_get(s, i) == sep {
+      r := list{sub(s, i + 1, j.contents - i - 1), ...r.contents}
+      j := i
+    }
+  }
+  list{sub(s, 0, j.contents), ...r.contents}
+}
diff --git a/tests/tests/src/ocaml_compat/Ocaml_String.resi b/tests/tests/src/ocaml_compat/Ocaml_String.resi
new file mode 100644
index 0000000000..a5bc660235
--- /dev/null
+++ b/tests/tests/src/ocaml_compat/Ocaml_String.resi
@@ -0,0 +1,250 @@
+// FIXME:
+//   This exists for compatibility reason.
+//   Move this into Pervasives or Core
+
+// Below is all deprecated and should be removed in v13
+
+/** Return the length (number of characters) of the given string. */
+@deprecated("Use Core instead. This will be removed in v13")
+external length: string => int = "%string_length"
+
+/** [String.get s n] returns the character at index [n] in string [s].
+   You can also write [s.[n]] instead of [String.get s n].
+
+   Raise [Invalid_argument] if [n] not a valid index in [s]. */
+@deprecated("Use Core instead. This will be removed in v13")
+@send
+external get: (string, int) => char = "codePointAt"
+
+/** [String.make n c] returns a fresh string of length [n],
+   filled with the character [c]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let make: (int, char) => string
+
+/** [String.init n f] returns a string of length [n], with character
+    [i] initialized to the result of [f i] (called in increasing
+    index order).
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let init: (int, int => char) => string
+
+/** [String.sub s start len] returns a fresh string of length [len],
+   containing the substring of [s] that starts at position [start] and
+   has length [len].
+
+   Raise [Invalid_argument] if [start] and [len] do not
+   designate a valid substring of [s]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let sub: (string, int, int) => string
+
+/** [String.concat sep sl] concatenates the list of strings [sl],
+    inserting the separator string [sep] between each.
+
+    Raise [Invalid_argument] if the result is longer than
+    {!Sys.max_string_length} bytes. */
+@deprecated("Use Core instead. This will be removed in v13")
+let concat: (string, list<string>) => string
+
+/** [String.iter f s] applies function [f] in turn to all
+   the characters of [s].  It is equivalent to
+   [f s.[0]; f s.[1]; ...; f s.[String.length s - 1]; ()]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let iter: (char => unit, string) => unit
+
+/** Same as {!String.iter}, but the
+   function is applied to the index of the element as first argument
+   (counting from 0), and the character itself as second argument.
+   @since 4.00.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let iteri: ((int, char) => unit, string) => unit
+
+/** [String.map f s] applies function [f] in turn to all the
+    characters of [s] (in increasing index order) and stores the
+    results in a new string that is returned.
+    @since 4.00.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let map: (char => char, string) => string
+
+/** [String.mapi f s] calls [f] with each character of [s] and its
+    index (in increasing index order) and stores the results in a new
+    string that is returned.
+    @since 4.02.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let mapi: ((int, char) => char, string) => string
+
+/** Return a copy of the argument, without leading and trailing
+   whitespace.  The characters regarded as whitespace are: [' '],
+   ['\x0c'], ['\n'], ['\r'], and ['\t'].  If there is neither leading nor
+   trailing whitespace character in the argument, return the original
+   string itself, not a copy.
+   @since 4.00.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+@send
+external trim: string => string = "trim"
+
+/** Return a copy of the argument, with special characters
+    represented by escape sequences, following the lexical
+    conventions of OCaml.
+    All characters outside the ASCII printable range (32..126) are
+    escaped, as well as backslash and double-quote.
+
+    If there is no special character in the argument that needs
+    escaping, return the original string itself, not a copy.
+ */
+@deprecated("Use Core instead. This will be removed in v13")
+let escaped: string => string
+
+/** [String.index s c] returns the index of the first
+   occurrence of character [c] in string [s].
+
+   Raise [Not_found] if [c] does not occur in [s]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let index: (string, char) => int
+
+/** [String.index_opt s c] returns the index of the first
+    occurrence of character [c] in string [s], or
+    [None] if [c] does not occur in [s].
+    @since 4.05 */
+@deprecated("Use Core instead. This will be removed in v13")
+let index_opt: (string, char) => option<int>
+
+/** [String.rindex s c] returns the index of the last
+   occurrence of character [c] in string [s].
+
+   Raise [Not_found] if [c] does not occur in [s]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let rindex: (string, char) => int
+
+/** [String.rindex_opt s c] returns the index of the last occurrence
+    of character [c] in string [s], or [None] if [c] does not occur in
+    [s].
+    @since 4.05 */
+@deprecated("Use Core instead. This will be removed in v13")
+let rindex_opt: (string, char) => option<int>
+
+/** [String.index_from s i c] returns the index of the
+   first occurrence of character [c] in string [s] after position [i].
+   [String.index s c] is equivalent to [String.index_from s 0 c].
+
+   Raise [Invalid_argument] if [i] is not a valid position in [s].
+   Raise [Not_found] if [c] does not occur in [s] after position [i]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let index_from: (string, int, char) => int
+
+/** [String.index_from_opt s i c] returns the index of the
+    first occurrence of character [c] in string [s] after position [i]
+    or [None] if [c] does not occur in [s] after position [i].
+
+    [String.index_opt s c] is equivalent to [String.index_from_opt s 0 c].
+    Raise [Invalid_argument] if [i] is not a valid position in [s].
+
+    @since 4.05
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let index_from_opt: (string, int, char) => option<int>
+
+/** [String.rindex_from s i c] returns the index of the
+   last occurrence of character [c] in string [s] before position [i+1].
+   [String.rindex s c] is equivalent to
+   [String.rindex_from s (String.length s - 1) c].
+
+   Raise [Invalid_argument] if [i+1] is not a valid position in [s].
+   Raise [Not_found] if [c] does not occur in [s] before position [i+1]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let rindex_from: (string, int, char) => int
+
+/** [String.rindex_from_opt s i c] returns the index of the
+   last occurrence of character [c] in string [s] before position [i+1]
+   or [None] if [c] does not occur in [s] before position [i+1].
+
+   [String.rindex_opt s c] is equivalent to
+   [String.rindex_from_opt s (String.length s - 1) c].
+
+   Raise [Invalid_argument] if [i+1] is not a valid position in [s].
+
+    @since 4.05
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let rindex_from_opt: (string, int, char) => option<int>
+
+/** [String.contains s c] tests if character [c]
+   appears in the string [s]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let contains: (string, char) => bool
+
+/** [String.contains_from s start c] tests if character [c]
+   appears in [s] after position [start].
+   [String.contains s c] is equivalent to
+   [String.contains_from s 0 c].
+
+   Raise [Invalid_argument] if [start] is not a valid position in [s]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let contains_from: (string, int, char) => bool
+
+/** [String.rcontains_from s stop c] tests if character [c]
+   appears in [s] before position [stop+1].
+
+   Raise [Invalid_argument] if [stop < 0] or [stop+1] is not a valid
+   position in [s]. */
+@deprecated("Use Core instead. This will be removed in v13")
+let rcontains_from: (string, int, char) => bool
+
+/** Return a copy of the argument, with all lowercase letters
+   translated to uppercase, using the US-ASCII character set.
+   @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let uppercase_ascii: string => string
+
+/** Return a copy of the argument, with all uppercase letters
+   translated to lowercase, using the US-ASCII character set.
+   @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let lowercase_ascii: string => string
+
+/** Return a copy of the argument, with the first character set to uppercase,
+   using the US-ASCII character set.
+   @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let capitalize_ascii: string => string
+
+/** Return a copy of the argument, with the first character set to lowercase,
+   using the US-ASCII character set.
+   @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+let uncapitalize_ascii: string => string
+
+/** An alias for the type of strings. */
+@deprecated("Use `string` instead. This will be removed in v13")
+type t = string
+
+/** The comparison function for strings, with the same specification as
+    {!Pervasives.compare}.  Along with the type [t], this function [compare]
+    allows the module [String] to be passed as argument to the functors
+    {!Set.Make} and {!Map.Make}. */
+@deprecated("Use Core instead. This will be removed in v13")
+external compare: (t, t) => int = "%compare"
+
+/** The equal function for strings.
+    @since 4.03.0 */
+@deprecated("Use Core instead. This will be removed in v13")
+external equal: (t, t) => bool = "%equal"
+
+/** [String.split_on_char sep s] returns the list of all (possibly empty)
+    substrings of [s] that are delimited by the [sep] character.
+
+    The function's output is specified by the following invariants:
+
+    - The list is not empty.
+    - Concatenating its elements using [sep] as a separator returns a
+      string equal to the input ([String.concat (String.make 1 sep)
+      (String.split_on_char sep s) = s]).
+    - No string in the result contains the [sep] character.
+
+    @since 4.04.0
+*/
+@deprecated("Use Core instead. This will be removed in v13")
+let split_on_char: (char, string) => list<string>
+
+/* The following is for system use only. Do not call directly. */
+@deprecated("Use Core instead. This will be removed in v13") @send
+external unsafe_get: (string, int) => char = "codePointAt"
diff --git a/tests/tests/src/string_bound_get_test.js b/tests/tests/src/string_bound_get_test.js
index ce4117cece..f175f52790 100644
--- a/tests/tests/src/string_bound_get_test.js
+++ b/tests/tests/src/string_bound_get_test.js
@@ -4,16 +4,16 @@
 
 let v = "ghos";
 
-let u_a = v.codePointAt(0);
+let u_a = v[0];
 
 function u_b() {
-  return v.codePointAt(-1);
+  return v[-1];
 }
 
-let u_c = "ghos".codePointAt(0);
+let u_c = "ghos"[0];
 
 function u_d() {
-  return "ghos".codePointAt(-1);
+  return "ghos"[-1];
 }
 
 exports.v = v;
diff --git a/tests/tests/src/string_set.js b/tests/tests/src/string_set.js
index 2b1fdb6bbe..b5262a9fb0 100644
--- a/tests/tests/src/string_set.js
+++ b/tests/tests/src/string_set.js
@@ -280,6 +280,8 @@ function invariant(t) {
   return Set_gen.is_ordered(compare_elt, t);
 }
 
+let $$String;
+
 let empty = Set_gen.empty;
 
 let is_empty = Set_gen.is_empty;
@@ -312,6 +314,7 @@ let of_sorted_list = Set_gen.of_sorted_list;
 
 let of_sorted_array = Set_gen.of_sorted_array;
 
+exports.$$String = $$String;
 exports.compare_elt = compare_elt;
 exports.empty = empty;
 exports.is_empty = is_empty;
diff --git a/tests/tests/src/string_set.res b/tests/tests/src/string_set.res
index 493e3aabcd..14334124f3 100644
--- a/tests/tests/src/string_set.res
+++ b/tests/tests/src/string_set.res
@@ -22,6 +22,8 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
 
+module String = Ocaml_String
+
 type elt = string
 let compare_elt = String.compare
 type t = Set_gen.t<elt>
diff --git a/tests/tests/src/tagged_template_test.js b/tests/tests/src/tagged_template_test.js
index 5de91d68c8..457d8894e6 100644
--- a/tests/tests/src/tagged_template_test.js
+++ b/tests/tests/src/tagged_template_test.js
@@ -99,8 +99,11 @@ Mt.from_pair_suites("tagged templates", {
   }
 });
 
+let $$Array;
+
 let extraLength = 10;
 
+exports.$$Array = $$Array;
 exports.Pg = Pg;
 exports.table = table;
 exports.id = id;
diff --git a/tests/tests/src/tagged_template_test.res b/tests/tests/src/tagged_template_test.res
index 6ed29697d4..92c798724a 100644
--- a/tests/tests/src/tagged_template_test.res
+++ b/tests/tests/src/tagged_template_test.res
@@ -1,3 +1,5 @@
+module Array = Ocaml_Array
+
 module Pg = {
   @module("./tagged_template_lib.js") @taggedTemplate
   external sql: (array<string>, array<string>) => string = "sql"
diff --git a/tests/tests/src/tailcall_inline_test.js b/tests/tests/src/tailcall_inline_test.js
index 7171478bb0..ca75e120e6 100644
--- a/tests/tests/src/tailcall_inline_test.js
+++ b/tests/tests/src/tailcall_inline_test.js
@@ -3,7 +3,6 @@
 
 let Mt = require("./mt.js");
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 function f() {
   let f$1 = (_acc, _n) => {
@@ -20,7 +19,7 @@ function f() {
   };
   let v = Belt_Array.make(10, 0);
   for (let i = 0; i <= 9; ++i) {
-    Primitive_array.set(v, i, f$1(0, i));
+    v[i] = f$1(0, i);
   }
   return v;
 }
diff --git a/tests/tests/src/test_closure.js b/tests/tests/src/test_closure.js
index a44fb463e0..f428a3f74d 100644
--- a/tests/tests/src/test_closure.js
+++ b/tests/tests/src/test_closure.js
@@ -2,7 +2,6 @@
 'use strict';
 
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 let v = {
   contents: 0
@@ -11,9 +10,9 @@ let v = {
 function f() {
   let arr = Belt_Array.make(10, param => {});
   for (let i = 0; i <= 9; ++i) {
-    Primitive_array.set(arr, i, param => {
+    arr[i] = param => {
       v.contents = v.contents + i | 0;
-    });
+    };
   }
   return arr;
 }
diff --git a/tests/tests/src/test_cps.js b/tests/tests/src/test_cps.js
index 4c2e3b333f..67b6c0f289 100644
--- a/tests/tests/src/test_cps.js
+++ b/tests/tests/src/test_cps.js
@@ -2,7 +2,6 @@
 'use strict';
 
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 function f(_n, _acc) {
   while (true) {
@@ -23,7 +22,7 @@ function f(_n, _acc) {
 function test_closure() {
   let arr = Belt_Array.make(6, x => x);
   for (let i = 0; i <= 6; ++i) {
-    Primitive_array.set(arr, i, param => i);
+    arr[i] = param => i;
   }
   return arr;
 }
diff --git a/tests/tests/src/test_for_loop.js b/tests/tests/src/test_for_loop.js
index 3e1c842f68..44ee773e42 100644
--- a/tests/tests/src/test_for_loop.js
+++ b/tests/tests/src/test_for_loop.js
@@ -2,17 +2,16 @@
 'use strict';
 
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 function for_(x) {
   for (let i = 0, i_finish = (console.log("hi"), x.length); i <= i_finish; ++i) {
-    console.log(Primitive_array.get(x, i));
+    console.log(x[i]);
   }
 }
 
 function for_2(x) {
   for (let i = 0, i_finish = x.length; i <= i_finish; ++i) {
-    console.log(Primitive_array.get(x, i));
+    console.log(x[i]);
   }
 }
 
@@ -23,9 +22,9 @@ function for_3(x) {
   let arr = Belt_Array.map(x, param => (() => {}));
   for (let i = 0, i_finish = x.length; i <= i_finish; ++i) {
     let j = (i << 1);
-    Primitive_array.set(arr, i, () => {
+    arr[i] = () => {
       v.contents = v.contents + j | 0;
-    });
+    };
   }
   Belt_Array.forEach(arr, x => x());
   return v.contents;
@@ -39,9 +38,9 @@ function for_4(x) {
   for (let i = 0, i_finish = x.length; i <= i_finish; ++i) {
     let j = (i << 1);
     let k = (j << 1);
-    Primitive_array.set(arr, i, () => {
+    arr[i] = () => {
       v.contents = v.contents + k | 0;
-    });
+    };
   }
   Belt_Array.forEach(arr, x => x());
   return v.contents;
@@ -54,9 +53,9 @@ function for_5(x, u) {
   let arr = Belt_Array.map(x, param => (() => {}));
   for (let i = 0, i_finish = x.length; i <= i_finish; ++i) {
     let k = Math.imul((u << 1), u);
-    Primitive_array.set(arr, i, () => {
+    arr[i] = () => {
       v.contents = v.contents + k | 0;
-    });
+    };
   }
   Belt_Array.forEach(arr, x => x());
   return v.contents;
@@ -83,9 +82,9 @@ function for_6(x, u) {
       let k = Math.imul((u << 1), u);
       let h = (v5.contents << 1);
       v2.contents = v2.contents + 1 | 0;
-      Primitive_array.set(arr, i, () => {
+      arr[i] = () => {
         v.contents = (((((v.contents + k | 0) + v2.contents | 0) + u | 0) + v4.contents | 0) + v5.contents | 0) + h | 0;
-      });
+      };
     }
   }
   Belt_Array.forEach(arr, x => x());
diff --git a/tests/tests/src/test_google_closure.js b/tests/tests/src/test_google_closure.js
index c4a99fd263..ec2b89005b 100644
--- a/tests/tests/src/test_google_closure.js
+++ b/tests/tests/src/test_google_closure.js
@@ -2,7 +2,6 @@
 'use strict';
 
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 function f(a, b, param) {
   return a + b | 0;
@@ -24,7 +23,7 @@ let arr = Belt_Array.init(2, param => 0);
 
 for (let i = 0; i <= 1; ++i) {
   let f3$1 = extra => i + 1 | 0;
-  Primitive_array.set(arr, i, f3$1(2));
+  arr[i] = f3$1(2);
 }
 
 console.log([
diff --git a/tests/tests/src/test_literals.js b/tests/tests/src/test_literals.js
index bb9b374c58..6497150fe4 100644
--- a/tests/tests/src/test_literals.js
+++ b/tests/tests/src/test_literals.js
@@ -11,4 +11,4 @@ let bsconfig_json = "bsconfig.json";
 exports.node_modules = node_modules;
 exports.node_modules_length = node_modules_length;
 exports.bsconfig_json = bsconfig_json;
-/* No side effect */
+/* node_modules_length Not a pure module */
diff --git a/tests/tests/src/test_pervasive.js b/tests/tests/src/test_pervasive.js
index 05b423e121..6ec9dcd090 100644
--- a/tests/tests/src/test_pervasive.js
+++ b/tests/tests/src/test_pervasive.js
@@ -4,44 +4,6 @@
 let Belt_List = require("rescript/lib/js/Belt_List.js");
 let Pervasives = require("rescript/lib/js/Pervasives.js");
 
-let $at = Pervasives.Pervasives.$at;
-
-let Pervasives_failwith = Pervasives.Pervasives.failwith;
-
-let Pervasives_invalid_arg = Pervasives.Pervasives.invalid_arg;
-
-let Pervasives_Exit = Pervasives.Pervasives.Exit;
-
-let Pervasives_abs = Pervasives.Pervasives.abs;
-
-let Pervasives_lnot = Pervasives.Pervasives.lnot;
-
-let Pervasives_max_int = Pervasives.Pervasives.max_int;
-
-let Pervasives_min_int = Pervasives.Pervasives.min_int;
-
-let Pervasives_infinity = Pervasives.Pervasives.infinity;
-
-let Pervasives_neg_infinity = Pervasives.Pervasives.neg_infinity;
-
-let Pervasives_max_float = Pervasives.Pervasives.max_float;
-
-let Pervasives_min_float = Pervasives.Pervasives.min_float;
-
-let Pervasives_epsilon_float = Pervasives.Pervasives.epsilon_float;
-
-let Pervasives_classify_float = Pervasives.Pervasives.classify_float;
-
-let Pervasives_char_of_int = Pervasives.Pervasives.char_of_int;
-
-let Pervasives_string_of_bool = Pervasives.Pervasives.string_of_bool;
-
-let Pervasives_bool_of_string = Pervasives.Pervasives.bool_of_string;
-
-let Pervasives_bool_of_string_opt = Pervasives.Pervasives.bool_of_string_opt;
-
-let Pervasives_int_of_string_opt = Pervasives.Pervasives.int_of_string_opt;
-
 let Pervasives$1 = {
   length: Belt_List.length,
   size: Belt_List.size,
@@ -131,25 +93,26 @@ let Pervasives$1 = {
   setAssoc: Belt_List.setAssoc,
   sortU: Belt_List.sortU,
   sort: Belt_List.sort,
-  failwith: Pervasives_failwith,
-  invalid_arg: Pervasives_invalid_arg,
-  Exit: Pervasives_Exit,
-  abs: Pervasives_abs,
-  lnot: Pervasives_lnot,
-  max_int: Pervasives_max_int,
-  min_int: Pervasives_min_int,
-  infinity: Pervasives_infinity,
-  neg_infinity: Pervasives_neg_infinity,
-  max_float: Pervasives_max_float,
-  min_float: Pervasives_min_float,
-  epsilon_float: Pervasives_epsilon_float,
-  classify_float: Pervasives_classify_float,
-  char_of_int: Pervasives_char_of_int,
-  string_of_bool: Pervasives_string_of_bool,
-  bool_of_string: Pervasives_bool_of_string,
-  bool_of_string_opt: Pervasives_bool_of_string_opt,
-  int_of_string_opt: Pervasives_int_of_string_opt,
-  $at: $at
+  failwith: Pervasives.failwith,
+  invalid_arg: Pervasives.invalid_arg,
+  Exit: Pervasives.Exit,
+  abs: Pervasives.abs,
+  lnot: Pervasives.lnot,
+  max_int: Pervasives.max_int,
+  min_int: Pervasives.min_int,
+  infinity: Pervasives.infinity,
+  neg_infinity: Pervasives.neg_infinity,
+  max_float: Pervasives.max_float,
+  min_float: Pervasives.min_float,
+  epsilon_float: Pervasives.epsilon_float,
+  classify_float: Pervasives.classify_float,
+  char_of_int: Pervasives.char_of_int,
+  string_of_bool: Pervasives.string_of_bool,
+  bool_of_string: Pervasives.bool_of_string,
+  bool_of_string_opt: Pervasives.bool_of_string_opt,
+  int_of_string_opt: Pervasives.int_of_string_opt,
+  $at: Pervasives.$at,
+  panic: Pervasives.panic
 };
 
 function a0(prim) {
@@ -228,7 +191,7 @@ function a18(prim0, prim1) {
   return Math.pow(prim0, prim1);
 }
 
-let f = $at;
+let f = Pervasives.$at;
 
 exports.Pervasives = Pervasives$1;
 exports.f = f;
diff --git a/tests/tests/src/test_pervasives3.js b/tests/tests/src/test_pervasives3.js
index 50877f8288..3288799e75 100644
--- a/tests/tests/src/test_pervasives3.js
+++ b/tests/tests/src/test_pervasives3.js
@@ -4,64 +4,27 @@
 let Belt_List = require("rescript/lib/js/Belt_List.js");
 let Pervasives = require("rescript/lib/js/Pervasives.js");
 
-let $at = Pervasives.Pervasives.$at;
-
-let Pervasives_failwith = Pervasives.Pervasives.failwith;
-
-let Pervasives_invalid_arg = Pervasives.Pervasives.invalid_arg;
-
-let Pervasives_Exit = Pervasives.Pervasives.Exit;
-
-let Pervasives_abs = Pervasives.Pervasives.abs;
-
-let Pervasives_lnot = Pervasives.Pervasives.lnot;
-
-let Pervasives_max_int = Pervasives.Pervasives.max_int;
-
-let Pervasives_min_int = Pervasives.Pervasives.min_int;
-
-let Pervasives_infinity = Pervasives.Pervasives.infinity;
-
-let Pervasives_neg_infinity = Pervasives.Pervasives.neg_infinity;
-
-let Pervasives_max_float = Pervasives.Pervasives.max_float;
-
-let Pervasives_min_float = Pervasives.Pervasives.min_float;
-
-let Pervasives_epsilon_float = Pervasives.Pervasives.epsilon_float;
-
-let Pervasives_classify_float = Pervasives.Pervasives.classify_float;
-
-let Pervasives_char_of_int = Pervasives.Pervasives.char_of_int;
-
-let Pervasives_string_of_bool = Pervasives.Pervasives.string_of_bool;
-
-let Pervasives_bool_of_string = Pervasives.Pervasives.bool_of_string;
-
-let Pervasives_bool_of_string_opt = Pervasives.Pervasives.bool_of_string_opt;
-
-let Pervasives_int_of_string_opt = Pervasives.Pervasives.int_of_string_opt;
-
 let Pervasives$1 = {
-  failwith: Pervasives_failwith,
-  invalid_arg: Pervasives_invalid_arg,
-  Exit: Pervasives_Exit,
-  abs: Pervasives_abs,
-  lnot: Pervasives_lnot,
-  max_int: Pervasives_max_int,
-  min_int: Pervasives_min_int,
-  infinity: Pervasives_infinity,
-  neg_infinity: Pervasives_neg_infinity,
-  max_float: Pervasives_max_float,
-  min_float: Pervasives_min_float,
-  epsilon_float: Pervasives_epsilon_float,
-  classify_float: Pervasives_classify_float,
-  char_of_int: Pervasives_char_of_int,
-  string_of_bool: Pervasives_string_of_bool,
-  bool_of_string: Pervasives_bool_of_string,
-  bool_of_string_opt: Pervasives_bool_of_string_opt,
-  int_of_string_opt: Pervasives_int_of_string_opt,
-  $at: $at,
+  failwith: Pervasives.failwith,
+  invalid_arg: Pervasives.invalid_arg,
+  Exit: Pervasives.Exit,
+  abs: Pervasives.abs,
+  lnot: Pervasives.lnot,
+  max_int: Pervasives.max_int,
+  min_int: Pervasives.min_int,
+  infinity: Pervasives.infinity,
+  neg_infinity: Pervasives.neg_infinity,
+  max_float: Pervasives.max_float,
+  min_float: Pervasives.min_float,
+  epsilon_float: Pervasives.epsilon_float,
+  classify_float: Pervasives.classify_float,
+  char_of_int: Pervasives.char_of_int,
+  string_of_bool: Pervasives.string_of_bool,
+  bool_of_string: Pervasives.bool_of_string,
+  bool_of_string_opt: Pervasives.bool_of_string_opt,
+  int_of_string_opt: Pervasives.int_of_string_opt,
+  $at: Pervasives.$at,
+  panic: Pervasives.panic,
   length: Belt_List.length,
   size: Belt_List.size,
   head: Belt_List.head,
@@ -152,7 +115,7 @@ let Pervasives$1 = {
   sort: Belt_List.sort
 };
 
-let v = $at;
+let v = Pervasives.$at;
 
 exports.Pervasives = Pervasives$1;
 exports.v = v;
diff --git a/tests/tests/src/test_primitive.js b/tests/tests/src/test_primitive.js
index 5131f8dad1..e5367cca65 100644
--- a/tests/tests/src/test_primitive.js
+++ b/tests/tests/src/test_primitive.js
@@ -2,7 +2,6 @@
 'use strict';
 
 let Lazy = require("rescript/lib/js/Lazy.js");
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 function a4(prim) {
   return [
@@ -41,7 +40,7 @@ let v = [
 
 let xxx = "a";
 
-let a = xxx.codePointAt(0);
+let a = xxx[0];
 
 function u(b) {
   if (b) {
@@ -56,7 +55,7 @@ function f2(h, b, param) {
   return h(b ? 32 : 7);
 }
 
-Primitive_array.set(v, 1, 3.0);
+v[1] = 3.0;
 
 let unboxed_x = {
   u: 0,
diff --git a/tests/tests/src/test_runtime_encoding.js b/tests/tests/src/test_runtime_encoding.js
index 70454ad5e9..6bef667b3e 100644
--- a/tests/tests/src/test_runtime_encoding.js
+++ b/tests/tests/src/test_runtime_encoding.js
@@ -1,7 +1,6 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 'use strict';
 
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 function g(x) {
   return [
@@ -25,11 +24,11 @@ function fff(vv, uu) {
 }
 
 function a(x) {
-  return Primitive_array.get(x, 0);
+  return x[0];
 }
 
 function aa(x) {
-  return Primitive_array.get(x, 0);
+  return x[0];
 }
 
 function aaa(x) {
@@ -42,7 +41,7 @@ function aaaa(x) {
 
 function f(x) {
   for (let i = 0; i <= 10; ++i) {
-    Primitive_array.set(x, i, i);
+    x[i] = i;
   }
 }
 
diff --git a/tests/tests/src/test_string.js b/tests/tests/src/test_string.js
index a2db7217af..c850635499 100644
--- a/tests/tests/src/test_string.js
+++ b/tests/tests/src/test_string.js
@@ -13,7 +13,7 @@ function f(x) {
         RE_EXN_ID: "Assert_failure",
         _1: [
           "test_string.res",
-          5,
+          7,
           17
         ],
         Error: new Error()
@@ -39,6 +39,9 @@ function h(s) {
   return s.codePointAt(0) === /* 'a' */97;
 }
 
+let $$String;
+
+exports.$$String = $$String;
 exports.f = f;
 exports.a = a;
 exports.b = b;
diff --git a/tests/tests/src/test_string.res b/tests/tests/src/test_string.res
index c458f95f00..05b4711917 100644
--- a/tests/tests/src/test_string.res
+++ b/tests/tests/src/test_string.res
@@ -1,3 +1,5 @@
+module String = Ocaml_String
+
 let f = x =>
   switch x {
   | "aaaabb" => 0
diff --git a/tests/tests/src/test_string_const.js b/tests/tests/src/test_string_const.js
index 98f22306ad..a5c39aa243 100644
--- a/tests/tests/src/test_string_const.js
+++ b/tests/tests/src/test_string_const.js
@@ -19,6 +19,9 @@ try {
   }
 }
 
+let $$String;
+
+exports.$$String = $$String;
 exports.f = f;
 exports.hh = hh;
 /* f Not a pure module */
diff --git a/tests/tests/src/test_string_const.res b/tests/tests/src/test_string_const.res
index e9b89d5f35..613e183d58 100644
--- a/tests/tests/src/test_string_const.res
+++ b/tests/tests/src/test_string_const.res
@@ -1,3 +1,5 @@
+module String = Ocaml_String
+
 let f = String.get("ghsogh", 3)
 
 let hh = try String.get("ghsogh", -3) catch {
diff --git a/tests/tests/src/test_while_closure.js b/tests/tests/src/test_while_closure.js
index 6cf6e7cc09..cc31ce3aca 100644
--- a/tests/tests/src/test_while_closure.js
+++ b/tests/tests/src/test_while_closure.js
@@ -2,7 +2,6 @@
 'use strict';
 
 let Belt_Array = require("rescript/lib/js/Belt_Array.js");
-let Primitive_array = require("rescript/lib/js/Primitive_array.js");
 
 let v = {
   contents: 0
@@ -14,9 +13,9 @@ function f() {
   let n = 0;
   while (n < 10) {
     let j = n;
-    Primitive_array.set(arr, j, () => {
+    arr[j] = () => {
       v.contents = v.contents + j | 0;
-    });
+    };
     n = n + 1 | 0;
   };
 }