feat: introduce package for runfile helpers

Introduces a new package called `@bazel/runfiles` that
provides runfile helpers for Bazel with NodeJS.

The benefit of providing the helpers as a separate package
is that people can explicitly specify a dependency on
the helpers and also can get typings. The current best practice
of using a require w/ an environment variable is untyped and
prone to mistakes (and doesn't fit well into the Node/NPM ecosystem).

Author: devversion

BUILD.bazel

@@ -89,6 +89,7 @@ pkg_npm(
         "//internal/pkg_npm:package_contents",
         "//internal/pkg_web:package_contents",
         "//internal/providers:package_contents",
+        "//internal/runfiles:package_contents",
         "//third_party/github.com/bazelbuild/bazel:package_contents",
         "//third_party/github.com/bazelbuild/bazel-skylib:package_contents",
         "//third_party/github.com/bazelbuild/bazel/tools/bash/runfiles:package_contents",

commitlint.config.js

@@ -17,6 +17,7 @@ module.exports = {
         'labs',
         'protractor',
         'rollup',
+        'runfiles',
         'terser',
         'typescript',
         'worker',

examples/BUILD.bazel

@@ -65,6 +65,9 @@ example_integration_test(
 
 example_integration_test(
     name = "examples_create-react-app",
+    npm_packages = {
+        "//packages/runfiles:npm_package": "@bazel/runfiles",
+    },
 )
 
 example_integration_test(
@@ -92,6 +95,9 @@ example_integration_test(
 
 example_integration_test(
     name = "examples_closure",
+    npm_packages = {
+        "//packages/runfiles:npm_package": "@bazel/runfiles",
+    },
 )
 
 example_integration_test(

examples/closure/BUILD.bazel

@@ -16,6 +16,9 @@ google_closure_compiler(
 
 nodejs_test(
     name = "test",
-    data = ["bundle.js"],
+    data = [
+        "bundle.js",
+        "@npm//@bazel/runfiles",
+    ],
     entry_point = "test.js",
 )

examples/closure/package.json

@@ -1,6 +1,8 @@
 {
     "private": true,
+    "//comment": "TODO: Change runfiles dependency to an actual version once released.",
     "dependencies": {
+        "@bazel/runfiles": "latest",
         "google-closure-compiler": "20190729.0.0"
     }
 }

examples/closure/test.js

@@ -1,4 +1,4 @@
-const runfiles = require(process.env['BAZEL_NODE_RUNFILES_HELPER']);
+const {runfiles} = require('@bazel/runfiles');
 
 const closureOutput = runfiles.resolve('examples_closure/bundle.js');
 

examples/create-react-app/BUILD.bazel

@@ -59,7 +59,10 @@ react_scripts(
 
 nodejs_test(
     name = "build_smoke_test",
-    data = ["build"],
+    data = [
+        "build",
+        "@npm//@bazel/runfiles",
+    ],
     entry_point = "build_smoke_test.js",
 )
 

examples/create-react-app/build_smoke_test.js

@@ -1,6 +1,6 @@
 const assert = require('assert');
 const fs = require('fs');
-const runfiles = require(process.env['BAZEL_NODE_RUNFILES_HELPER']);
+const {runfiles} = require('@bazel/runfiles');
 
 // Make sure there's a file like build/static/js/main.12345678.chunk.js
 const jsDir = runfiles.resolvePackageRelative('build/static/js');

examples/create-react-app/package.json

@@ -16,8 +16,10 @@
     "react-scripts": "3.4.1",
     "typescript": "~3.7.2"
   },
+  "//comment": "TODO: Change runfiles dependency to an actual version once released.",
   "devDependencies": {
     "@bazel/ibazel": "^0.15.6",
+    "@bazel/runfiles": "latest",
     "patch-package": "^6.2.2"
   },
   "scripts": {

internal/js_library/js_library.bzl

@@ -38,10 +38,10 @@ _ATTRS = {
     ),
     "deps": attr.label_list(),
     "external_npm_package": attr.bool(
-        doc = """Internal use only. Indictates that this js_library target is one or more external npm packages in node_modules.
+        doc = """Internal use only. Indicates that this js_library target is one or more external npm packages in node_modules.
         This is used by the yarn_install & npm_install repository rules for npm dependencies installed by
         yarn & npm. When true, js_library will provide ExternalNpmPackageInfo.
-        
+
         It can also be used for user-managed npm dependencies if node_modules is layed out outside of bazel.
         For example,