Array.fromOneItem

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Next version
 
+### API changes
+
+- `Array.of1` https://github.com/rescript-association/rescript-core/pull/109
+
 ## 0.4.0
 
 ### API changes

src/Core__Array.res

@@ -245,3 +245,5 @@ let findMap = (arr, f) => {
 }
 
 @send external at: (array<'a>, int) => option<'a> = "at"
+
+@val external of1: 'a => array<'a> = "Array.of"

src/Core__Array.resi

@@ -969,3 +969,24 @@ let findMap: (array<'a>, 'a => option<'b>) => option<'b>
 */
 @send
 external at: (array<'a>, int) => option<'a> = "at"
+
+/**
+`of1` generates a new array from a single value. See [Array.of on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/of)
+
+## Examples
+
+```rescript
+3->Array.of1 // [3]
+undefined->Array.of1 // [undefined]
+Some("abc")->Array.of1 // [Some("abc")]
+[1,2,3]->Array.of1 // [[1,2,3]]
+{"x": 3, "y": 5}->Array.of1 // Some({"x": 3, "y": 5})
+```
+
+## Specifications
+
+- [Array.of MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/of)
+- [Array.of ECMAScript Language Specification](https://tc39.es/ecma262/multipage/indexed-collections.html#sec-array.of)
+*/
+@val
+external of1: 'a => array<'a> = "Array.of"

test/ArrayTests.mjs

@@ -401,7 +401,66 @@ Test.run([
 
           })), eq, undefined);
 
+function of1Test(a, title) {
+  Test.run([
+        [
+          "ArrayTests.res",
+          103,
+          22,
+          38
+        ],
+        "of1 : " + title + ""
+      ], Array.of(a), Caml_obj.equal, [a]);
+  Test.run([
+        [
+          "ArrayTests.res",
+          104,
+          22,
+          38
+        ],
+        "of1 : " + title + ""
+      ], Array.of(a).length, eq, 1);
+  Test.run([
+        [
+          "ArrayTests.res",
+          105,
+          22,
+          38
+        ],
+        "of1 : " + title + ""
+      ], Array.of(a)[0], (function (i, j) {
+          return i === j;
+        }), a);
+}
+
+var m = Array.of({
+      x: 3,
+      y: 5
+    });
+
+of1Test(3, "Single integer");
+
+of1Test("abc", "Single string");
+
+of1Test(undefined, "undefined");
+
+of1Test(null, "null");
+
+of1Test([
+      1,
+      2,
+      3
+    ], "full array of integers");
+
+of1Test([], "empty array");
+
+of1Test(5, "Some");
+
+of1Test(undefined, "None");
+
 export {
   eq ,
+  of1Test ,
+  m ,
 }
 /*  Not a pure module */

test/ArrayTests.res

@@ -98,3 +98,18 @@ Test.run(
   eq,
   None,
 )
+
+let of1Test = (a, title) => {
+  Test.run(__POS_OF__(`of1 : ${title}`), Array.of1(a), (i, j) => i == j, [a])
+  Test.run(__POS_OF__(`of1 : ${title}`), Array.of1(a)->Array.length, eq, 1)
+  Test.run(__POS_OF__(`of1 : ${title}`), Array.of1(a)->Array.getUnsafe(0), (i, j) => i === j, a)
+}
+let m = {"x": 3, "y": 5}->Array.of1
+3->of1Test("Single integer")
+"abc"->of1Test("Single string")
+undefined->of1Test("undefined")
+null->of1Test("null")
+[1, 2, 3]->of1Test("full array of integers")
+[]->of1Test("empty array")
+Some(5)->of1Test("Some")
+None->of1Test("None")

test/TestSuite.mjs

@@ -28,6 +28,10 @@ var Concurrently = PromiseTest.Concurrently;
 
 var panicTest = ErrorTests.panicTest;
 
+var of1Test = ArrayTests.of1Test;
+
+var m = ArrayTests.m;
+
 var $$catch = IntTests.$$catch;
 
 var forEachIfOkCallFunction = ResultTests.forEachIfOkCallFunction;
@@ -61,6 +65,8 @@ export {
   Catching ,
   Concurrently ,
   panicTest ,
+  of1Test ,
+  m ,
   $$catch ,
   forEachIfOkCallFunction ,
   forEachIfErrorDoNotCallFunction ,