feat: add esbuild package

WORKSPACE

@@ -129,6 +129,11 @@ browser_repositories(
     firefox = True,
 )
 
+# Setup esbuild dependencies
+load("//packages/esbuild:index.bzl", "esbuild_repository")
+
+esbuild_repository(name = "esbuild")
+
 #
 # Dependencies to run stardoc & generating documentation
 #

docs/BUILD.bazel

@@ -81,6 +81,7 @@ rules_nodejs_docs(
         "Rollup": "//packages/rollup:README.md",
         "Terser": "//packages/terser:README.md",
         "TypeScript": "//packages/typescript:README.md",
+        "esbuild": "//packages/esbuild:README.md",
     },
     tags = [
         "fix-windows",

internal/linker/link_node_modules.bzl

@@ -19,7 +19,7 @@ def _debug(vars, *args):
         print("[link_node_modules.bzl]", *args)
 
 # Arbitrary name; must be chosen to globally avoid conflicts with any other aspect
-_ASPECT_RESULT_NAME = "link_node_modules__aspect_result"
+ASPECT_RESULT_NAME = "link_node_modules__aspect_result"
 
 # Traverse 'srcs' in addition so that we can go across a genrule
 _MODULE_MAPPINGS_DEPS_NAMES = ["data", "deps", "srcs"]
@@ -81,7 +81,7 @@ def write_node_modules_manifest(ctx, extra_data = [], mnemonic = None, link_work
                 fail("All npm dependencies need to come from a single workspace. Found '%s' and '%s'." % (node_modules_root, possible_root))
 
         # ...first-party packages to be linked into the node_modules tree
-        for k, v in getattr(dep, _ASPECT_RESULT_NAME, {}).items():
+        for k, v in getattr(dep, ASPECT_RESULT_NAME, {}).items():
             if _link_mapping(dep.label, mappings, k, v):
                 # Special case for ts_library module_name for legacy behavior and for AMD name
                 # work-around. Do not propagate tslibrary root type to runtime as it is not
@@ -126,7 +126,7 @@ def _get_module_mappings(target, ctx):
     # Propogate transitive mappings
     for name in _MODULE_MAPPINGS_DEPS_NAMES:
         for dep in getattr(ctx.rule.attr, name, []):
-            for k, v in getattr(dep, _ASPECT_RESULT_NAME, {}).items():
+            for k, v in getattr(dep, ASPECT_RESULT_NAME, {}).items():
                 # A package which was reachable transitively via a *_binary or *_test
                 # rule is assumed to be in the runfiles of that binary,
                 # so we switch the linker target root.
@@ -172,9 +172,9 @@ def _get_module_mappings(target, ctx):
 
 def _module_mappings_aspect_impl(target, ctx):
     # Use a dictionary to construct the result struct
-    # so that we can reference the _ASPECT_RESULT_NAME variable
+    # so that we can reference the ASPECT_RESULT_NAME variable
     return struct(**{
-        _ASPECT_RESULT_NAME: _get_module_mappings(target, ctx),
+        ASPECT_RESULT_NAME: _get_module_mappings(target, ctx),
     })
 
 module_mappings_aspect = aspect(

packages/esbuild/BUILD.bazel

@@ -0,0 +1,83 @@
+# Copyright 2020 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
+load("@build_bazel_rules_nodejs//:tools/defaults.bzl", "codeowners", "pkg_npm")
+load("@build_bazel_rules_nodejs//tools/stardoc:index.bzl", "stardoc")
+load("//third_party/github.com/bazelbuild/bazel-skylib:rules/copy_file.bzl", "copy_file")
+
+package(default_visibility = ["//visibility:public"])
+
+codeowners(
+    teams = ["@mattem"],
+)
+
+bzl_library(
+    name = "bzl",
+    srcs = glob(["**/*.bzl"]),
+    deps = [
+        "@bazel_skylib//lib:paths",
+        "@build_bazel_rules_nodejs//:bzl",
+        "@build_bazel_rules_nodejs//internal/common:bzl",
+        "@build_bazel_rules_nodejs//internal/node:bzl",
+    ],
+)
+
+stardoc(
+    name = "docs",
+    testonly = True,
+    out = "index.md",
+    input = "index.bzl",
+    tags = ["fix-windows"],
+    deps = [":bzl"],
+)
+
+genrule(
+    name = "generate_README",
+    srcs = [
+        "_README.md",
+        "index.md",
+    ],
+    outs = ["README.md"],
+    cmd = """cat $(execpath _README.md) $(execpath index.md) | sed 's/^##/\\\n##/' > $@""",
+    tags = ["fix-windows"],
+    visibility = ["//docs:__pkg__"],
+)
+
+copy_file(
+    name = "npm_version_check",
+    src = "//internal:npm_version_check.js",
+    out = ":npm_version_check.js",
+)
+
+pkg_npm(
+    name = "npm_package",
+    srcs = [
+        "esbuild.bzl",
+        "esbuild_repo.bzl",
+        "helpers.bzl",
+        "index.bzl",
+        "package.json",
+    ],
+    build_file_content = " ",
+    deps = [
+        ":npm_version_check",
+    ] + select({
+        # FIXME: fix stardoc on Windows; //packages/karma:index.md generation fails with:
+        #   ERROR: D:/b/62unjjin/external/npm_bazel_karma/BUILD.bazel:65:1: Couldn't build file
+        #   external/npm_bazel_karma/docs.raw: Generating proto for Starlark doc for docs failed (Exit 1)
+        "@bazel_tools//src/conditions:windows": [],
+        "//conditions:default": [":generate_README"],
+    }),
+)

packages/esbuild/_README.md

@@ -0,0 +1,60 @@
+# esbuild rules for Bazel
+
+The esbuild rules runs the [esbuild](https://github.com/evanw/esbuild) bundler tool with Bazel.
+
+## Installation
+
+Add the `@bazel/esbuild` npm packages to your `devDependencies` in `package.json`.
+
+```
+npm install --save-dev @bazel/esbuild
+```
+or using yarn
+```
+yarn add -D @bazel/esbuild
+```
+
+Add the esbuild repository to the `WORKSPACE` file
+
+```python
+load("@npm//@bazel/esbuild:index.bzl", "esbuild_repository")
+
+esbuild_repository(name = "esbuild")
+```
+
+The version of `esbuild` can be specified by passing the `version` and `platform_sha` attributes
+
+```python
+load("@npm//@bazel/esbuild:index.bzl", "esbuild_repository")
+
+esbuild_repository(
+    name = "esbuild",
+    version = "0.7.19",
+    platform_sha = {
+        "darwin_64": "deadf43c0868430983234f90781e1b542975a2bc3549b2353303fac236816149",
+        "linux_64": "2d25ad82dba8f565e8766b838acd3b966f9a2417499105ec10afb01611594ef1",
+        "windows_64": "135b2ff549d4b1cfa4f8e2226f85ee97641b468aaced7585112ebe8c0af2d766",
+    }
+)
+```
+
+## Example use of esbuild
+
+The `esbuild` rule can take a JS or TS dependency tree and bundle it to a single file, or split across multiple files, outputting a directory. 
+
+```python
+ts_library(
+    name = "lib",
+    srcs = ["a.ts"],
+)
+
+esbuild(
+    name = "bundle",
+    entry_point = "a.ts",
+    deps = [":lib"],
+)
+```
+
+The above will create three output files, `bundle.js`, `bundle.js.map` and `bundle_metadata.json` which contains the bundle metadata to aid in debugging and resoloution tracing.
+
+Further options for minifying and splitting are available.