feat: add esbuild package

WORKSPACE

@@ -155,6 +155,11 @@ 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",

packages/esbuild/BUILD.bazel

@@ -0,0 +1,54 @@
+# 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")
+load("@build_bazel_rules_nodejs//tools/stardoc:index.bzl", "stardoc")
+
+package(default_visibility = ["//visibility:public"])
+
+codeowners(
+    teams = ["@mattem"],
+)
+
+bzl_library(
+    name = "bzl",
+    srcs = glob(["**/*.bzl"]),
+    deps = [
+        "@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__"],
+)

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 avialable.

packages/esbuild/esbuild.bzl

@@ -0,0 +1,207 @@
+"""
+esbuild rule
+"""
+
+load("@build_bazel_rules_nodejs//:providers.bzl", "JSEcmaScriptModuleInfo", "JSModuleInfo", "NpmPackageInfo", "node_modules_aspect")
+load("@build_bazel_rules_nodejs//internal/linker:link_node_modules.bzl", "module_mappings_aspect")
+
+def _strip_ext(f):
+    return f.short_path[:-len(f.extension) - 1]
+
+def _resolve_js_input(f, inputs):
+    if f.extension == "js" or f.extension == "mjs":
+        return f
+
+    no_ext = _strip_ext(f)
+    for i in inputs:
+        if i.extension == "js" or i.extension == "mjs":
+            if _strip_ext(i) == no_ext:
+                return i
+    fail("Could not find corresponding javascript entry point for %s. Add the %s.js to your deps." % (f.path, no_ext))
+
+def _filter_js(files):
+    return [f for f in files if f.extension == "js" or f.extension == "mjs"]
+
+def _esbuild_impl(ctx):
+    # For each dep, JSEcmaScriptModuleInfo is used if found, then JSModuleInfo and finally
+    # the DefaultInfo files are used if the former providers are not found.
+    deps_depsets = []
+    for dep in ctx.attr.deps:
+        if JSEcmaScriptModuleInfo in dep:
+            deps_depsets.append(dep[JSEcmaScriptModuleInfo].sources)
+        elif JSModuleInfo in dep:
+            deps_depsets.append(dep[JSModuleInfo].sources)
+        elif hasattr(dep, "files"):
+            deps_depsets.append(dep.files)
+
+        if NpmPackageInfo in dep:
+            deps_depsets.append(dep[NpmPackageInfo].sources)
+
+    deps_inputs = depset(transitive = deps_depsets).to_list()
+    inputs = _filter_js(ctx.files.entry_point) + ctx.files.srcs + deps_inputs
+
+    metafile = ctx.actions.declare_file("%s_metadata.json" % ctx.attr.name)
+    outputs = [metafile]
+
+    entry_point = _resolve_js_input(ctx.file.entry_point, inputs)
+
+    args = ctx.actions.args()
+    args.add("--bundle", entry_point.path)
+    args.add("--sourcemap")
+    args.add_joined(["--platform", ctx.attr.platform], join_with = "=")
+    args.add_joined(["--target", ctx.attr.target], join_with = "=")
+    args.add_joined(["--log-level", "info"], join_with = "=")
+    args.add_joined(["--metafile", metafile.path], join_with = "=")
+    args.add_joined(["--define:process.env.NODE_ENV", '"production"'], join_with = "=")
+
+    # disable the error limit and show all errors
+    args.add_joined(["--error-limit", "0"], join_with = "=")
+
+    if ctx.attr.splitting:
+        js_out = ctx.actions.declare_directory("%s" % ctx.attr.name)
+        outputs.append(js_out)
+
+        args.add("--splitting")
+        args.add_joined(["--format", "esm"], join_with = "=")
+        args.add_joined(["--outdir", js_out.path], join_with = "=")
+    else:
+        js_out = ctx.outputs.output
+        js_out_map = ctx.outputs.output_map
+        outputs.extend([js_out, js_out_map])
+
+        if ctx.attr.format:
+            args.add_joined(["--format", ctx.attr.format], join_with = "=")
+
+        args.add_joined(["--outfile", js_out.path], join_with = "=")
+
+    if len(ctx.attr.module_mappings):
+        rel_path_to_root = "/".join([".." for seg in ctx.build_file_path.split("/")[:-1]])
+
+        # generate a tsconfig.json file with module mappings
+        # we might be able to figure these out from the DeclarationInfo on the deps?
+        tsconfig = """{"compilerOptions":{"baseUrl":"%s","rootDirs":["."],"paths":%s}}""" % (rel_path_to_root, ctx.attr.module_mappings)
+
+        tsconfig_file = ctx.actions.declare_file("%s_tsconfig.json" % ctx.attr.name)
+        inputs.append(tsconfig_file)
+        ctx.actions.write(tsconfig_file, tsconfig)
+
+        args.add_joined(["--tsconfig", tsconfig_file.path], join_with = "=")
+
+    for ext in ctx.attr.external:
+        args.add("--external:%s" % ext)
+
+    if ctx.attr.minify:
+        args.add("--minify")
+
+    ctx.actions.run(
+        inputs = inputs,
+        outputs = outputs,
+        executable = ctx.executable.esbuild,
+        arguments = [args],
+        progress_message = "%s Javascript %s [esbuild]" % ("Bundling" if not ctx.attr.splitting else "Splitting", entry_point.short_path),
+        execution_requirements = {
+            "no-remote-exec": "1",
+        },
+    )
+
+    return [
+        DefaultInfo(files = depset(outputs)),
+    ]
+
+esbuild_bundle = rule(
+    attrs = {
+        "deps": attr.label_list(
+            aspects = [module_mappings_aspect, node_modules_aspect],
+            doc = "A list of direct dependencies that are required to build the bundle",
+        ),
+        "entry_point": attr.label(
+            mandatory = True,
+            allow_single_file = True,
+            doc = "The bundle's entry point (e.g. your main.js or app.js or index.js)",
+        ),
+        "esbuild": attr.label(
+            allow_single_file = True,
+            default = "@esbuild//:bin/esbuild",
+            executable = True,
+            cfg = "exec",
+            doc = "An executable for the esbuild binary, can be overriden if a custom esbuild binary is needed",
+        ),
+        "external": attr.string_list(
+            default = [],
+            doc = "A list of module names that are treated as external and not included in the resulting bundle",
+        ),
+        "format": attr.string(
+            values = ["iife", "cjs", "esm", ""],
+            mandatory = False,
+            doc = """The output format of the bundle, defaults to iife when platform is browser
+and cjs when platform is node. If performing code splitting, defaults to esm""",
+        ),
+        "minify": attr.bool(
+            default = False,
+            doc = "If true, produce a minified output",
+        ),
+        "module_mappings": attr.string_list_dict(
+            doc = """A tsconfig style mapping of module names to paths for module import resolution.
+To import from 'lib', set the module mapping to the path to the files:
+
+```python
+module_mappings = {
+    "lib": ["path/to/module"],
+},
+```""",
+        ),
+        "output": attr.output(
+            mandatory = False,
+            doc = "Name of the output file when bundling",
+        ),
+        "output_map": attr.output(
+            mandatory = False,
+            doc = "Name of the output source map when bundling",
+        ),
+        "platform": attr.string(
+            default = "browser",
+            values = ["node", "browser", ""],
+            doc = "The platform to bundle for",
+        ),
+        "splitting": attr.bool(
+            default = False,
+            doc = """If true, esbuild produces an output directory containing all the output files from code splitting 
+            """,
+        ),
+        "srcs": attr.label_list(
+            allow_files = True,
+            default = [],
+            doc = """Non-entry point JavaScript source files from the workspace.
+
+You must not repeat file(s) passed to entry_point""",
+        ),
+        "target": attr.string(
+            default = "es2015",
+            doc = "Language target for esbuild",
+        ),
+    },
+    implementation = _esbuild_impl,
+)
+
+def esbuild(name, splitting = False, **kwargs):
+    """esbuild helper macro around the `esbuild_bundle` rule
+
+    Args:
+        name: The name used for this rule and output files
+        splitting: If `True`, produce a code split bundle in an output directory
+        **kwargs: All other args from `esbuild_bundle`
+    """
+
+    if splitting == True:
+        esbuild_bundle(
+            name = name,
+            splitting = True,
+            **kwargs
+        )
+    else:
+        esbuild_bundle(
+            name = name,
+            output = "%s.js" % name,
+            output_map = "%s.js.map" % name,
+            **kwargs
+        )