feat(terser): introduce @bazel/terser package

This is a clean implementation starting from what we were running in the built-in rollup_bundle rule.
It doesn't yet incorporate our new JS Providers design; that will come next. For now it just understands immediate .js inputs

commitlint.config.js

@@ -18,6 +18,7 @@ module.exports = {
         'protractor',
         'stylus',
         'rollup',
+        'terser',
         'typescript',
         'worker',
       ]

docs/BUILD.bazel

@@ -41,6 +41,7 @@ _PACKAGE_READMES = {
     "Less": "//packages/less:README.md",
     "Protractor": "//packages/protractor:README.md",
     "Stylus": "//packages/stylus:README.md",
+    "Terser": "//packages/terser:README.md",
     "TypeScript": "//packages/typescript:README.md",
 }
 

docs/Terser.md

@@ -0,0 +1,113 @@
+---
+title: Terser
+layout: default
+stylesheet: docs
+---
+# Terser rules for Bazel
+
+**WARNING: this is beta-quality software. Breaking changes are likely. Not recommended for production use without expert support.**
+
+The Terser rules run the Terser JS minifier with Bazel.
+
+Wraps the Terser CLI documented at https://github.com/terser-js/terser#command-line-usage
+
+
+## Installation
+
+Add the `@bazel/terser` npm package to your `devDependencies` in `package.json`.
+
+Your `WORKSPACE` should declare a `yarn_install` or `npm_install` rule named `npm`.
+It should then install the rules found in the npm packages using the `install_bazel_dependencies` function.
+See https://github.com/bazelbuild/rules_nodejs/#quickstart
+
+This causes the `@bazel/terser` package to be installed as a Bazel workspace named `npm_bazel_terser`.
+
+
+## Installing with self-managed dependencies
+
+If you didn't use the `yarn_install` or `npm_install` rule to create an `npm` workspace, you'll have to declare a rule in your root `BUILD.bazel` file to execute terser:
+
+```python
+# Create a terser rule to use in terser_minified#terser_bin
+# attribute when using self-managed dependencies
+nodejs_binary(
+    name = "terser_bin",
+    entry_point = "//:node_modules/terser/bin/uglifyjs",
+    # Point bazel to your node_modules to find the entry point
+    node_modules = ["//:node_modules"],
+)
+```
+
+[name]: https://bazel.build/docs/build-ref.html#name
+[label]: https://bazel.build/docs/build-ref.html#labels
+[labels]: https://bazel.build/docs/build-ref.html#labels
+
+
+## terser_minified
+
+Run the terser minifier.
+
+Typical example:
+```python
+load("@npm_bazel_terser//:index.bzl", "terser_minified")
+
+terser_minified(
+    name = "out.min",
+    src = "input.js",
+    config_file = "terser_config.json",
+)
+```
+
+Note that the `name` attribute determines what the resulting files will be called.
+
+
+
+### Usage
+
+```
+terser_minified(name, config_file, debug, sourcemap, src, terser_bin)
+```
+
+
+
+#### `name`
+(*[name], mandatory*): A unique name for this target.
+
+
+#### `config_file`
+(*[label]*): A JSON file containing Terser minify() options.
+
+This is the file you would pass to the --config-file argument in terser's CLI.
+https://github.com/terser-js/terser#minify-options documents the content of the file.
+
+Bazel will make a copy of your config file, treating it as a template.
+If you use the magic strings `bazel_debug` or `bazel_no_debug`, these will be
+replaced with `true` and `false` respecting the value of the `debug` attribute
+or the `--define=DEBUG=true` bazel flag.
+
+If this isn't supplied, Bazel will use a default config file.
+
+
+#### `debug`
+(*Boolean*): Configure terser to produce more readable output.
+
+Instead of setting this attribute, consider setting the DEBUG variable instead
+bazel build --define=DEBUG=true //my/terser:target
+so that it only affects the current build.
+
+
+#### `sourcemap`
+(*Boolean*): Whether to produce a .js.map file for each .js output
+
+
+#### `src`
+(*[label], mandatory*): A JS file, or a rule producing .js as its default output
+
+Note that you can pass multiple files to terser, which it will bundle together.
+If you want to do this, you can pass a filegroup here.
+
+
+#### `terser_bin`
+(*[label]*): An executable target that runs Terser
+
+

docs/_includes/drawer.html

@@ -40,6 +40,12 @@
             <li><a href="Jasmine.html">Jasmine</a></li>
           </ul>
         </li>
+        <li>
+          <span class="drawer-nav-title">Optimizers</span>
+          <ul>
+            <li><a href="Terser.html">Terser</a></li>
+          </ul>
+        </li>
         <li>
           <span class="drawer-nav-title">Deployment</span>
           <ul>

e2e/BUILD.bazel

@@ -96,6 +96,13 @@ e2e_integration_test(
     },
 )
 
+e2e_integration_test(
+    name = "e2e_terser",
+    npm_packages = {
+        "//packages/terser:npm_package": "@bazel/terser",
+    },
+)
+
 e2e_integration_test(
     name = "e2e_ts_devserver",
     npm_packages = {

e2e/index.bzl

@@ -13,6 +13,7 @@ ALL_E2E = [
     "stylus",
     "symlinked_node_modules_npm",
     "symlinked_node_modules_yarn",
+    "terser",
     "ts_auto_deps",
     "ts_devserver",
     "typescript",

e2e/terser/.bazelrc

@@ -0,0 +1 @@
+import %workspace%/../../common.bazelrc

e2e/terser/BUILD.bazel

@@ -0,0 +1,27 @@
+load("@build_bazel_rules_nodejs//:defs.bzl", "nodejs_test")
+load("@npm_bazel_terser//:index.bzl", "terser_minified")
+
+terser_minified(
+    name = "out.min",
+    src = "input.js",
+)
+
+nodejs_test(
+    name = "test",
+    data = ["out.min.js"],
+    entry_point = ":test.js",
+)
+
+# For testing from the root workspace of this repository with bazel_integration_test.
+filegroup(
+    name = "all_files",
+    srcs = glob(
+        include = ["**/*"],
+        exclude = [
+            "bazel-out/**/*",
+            "dist/**/*",
+            "node_modules/**/*",
+        ],
+    ),
+    visibility = ["//visibility:public"],
+)

e2e/terser/WORKSPACE

@@ -0,0 +1,38 @@
+# Copyright 2018 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.
+
+workspace(
+    name = "e2e_terser",
+    managed_directories = {"@npm": ["node_modules"]},
+)
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "build_bazel_rules_nodejs",
+    sha256 = "3356c6b767403392bab018ce91625f6d15ff8f11c6d772dc84bc9cada01c669a",
+    urls = ["https://github.com/bazelbuild/rules_nodejs/releases/download/0.36.1/rules_nodejs-0.36.1.tar.gz"],
+)
+
+load("@build_bazel_rules_nodejs//:defs.bzl", "yarn_install")
+
+yarn_install(
+    name = "npm",
+    package_json = "//:package.json",
+    yarn_lock = "//:yarn.lock",
+)
+
+load("@npm//:install_bazel_dependencies.bzl", "install_bazel_dependencies")
+
+install_bazel_dependencies()

e2e/terser/input.js

@@ -0,0 +1,2 @@
+const somelongname = 1;
+console.error(somelongname);

e2e/terser/package.json

@@ -0,0 +1,10 @@
+{
+    "name": "e2e-terser",
+    "private": true,
+    "devDependencies": {
+        "@bazel/terser": "latest"
+    },
+    "scripts": {
+      "test": "bazel test ..."
+    }
+}

e2e/terser/test.js

@@ -0,0 +1,5 @@
+const fs = require('fs');
+const content = fs.readFileSync(require.resolve(__dirname + '/out.min.js'), 'utf-8');
+if (content.indexOf('console.error(1)') < 1) {
+  console.error(content), process.exitCode = 1;
+}

internal/golden_file_test/BUILD.bazel

@@ -0,0 +1,3 @@
+package(default_visibility = ["//visibility:public"])
+
+exports_files(["bin.js"])

internal/golden_file_test/bin.js

@@ -0,0 +1,35 @@
+const fs = require('fs');
+const path = require('path');
+const unidiff = require('unidiff');
+
+function main(args) {
+  const [mode, golden, actual] = args;
+  const actualContents = fs.readFileSync(require.resolve(actual), 'utf-8').replace(/\r\n/g, '\n');
+  const goldenContents = fs.readFileSync(require.resolve(golden), 'utf-8').replace(/\r\n/g, '\n');
+
+  if (actualContents !== goldenContents) {
+    if (mode === '--out') {
+      // Write to golden file
+      fs.writeFileSync(require.resolve(golden), actualContents);
+      console.error(`Replaced ${path.join(process.cwd(), golden)}`);
+    } else if (mode === '--verify') {
+      // Generated does not match golden
+      const diff = unidiff.diffLines(goldenContents, actualContents);
+      const prettyDiff = unidiff.formatLines(diff, {aname: golden, bname: actual});
+      throw new Error(`Actual output doesn't match golden file:
+      
+${prettyDiff}
+      
+Update the golden file:
+
+            bazel run ${process.env['BAZEL_TARGET'].replace(/_bin$/, '')}.accept
+`);
+    } else {
+      throw new Error('unknown mode', mode);
+    }
+  }
+}
+
+if (require.main === module) {
+  main(process.argv.slice(2));
+}

internal/golden_file_test/golden_file_test.bzl

@@ -0,0 +1,24 @@
+"Convenience for testing that an output matches a file"
+
+load("@build_bazel_rules_nodejs//:defs.bzl", "nodejs_binary", "nodejs_test")
+
+def golden_file_test(name, golden, actual, **kwargs):
+    data = [golden, actual, "@npm//unidiff"]
+
+    loc = "$(location %s)"
+    nodejs_test(
+        name = name,
+        entry_point = "@build_bazel_rules_nodejs//internal/golden_file_test:bin.js",
+        templated_args = ["--verify", loc % golden, loc % actual],
+        data = data,
+        **kwargs
+    )
+
+    nodejs_binary(
+        name = name + ".accept",
+        testonly = True,
+        entry_point = "@build_bazel_rules_nodejs//internal/golden_file_test:bin.js",
+        templated_args = ["--out", loc % golden, loc % actual],
+        data = data,
+        **kwargs
+    )

package.json

@@ -50,6 +50,7 @@
         "semver": "5.6.0",
         "shelljs": "0.8.3",
         "sinon": "^7.3.2",
+        "source-map": "^0.7.3",
         "source-map-support": "0.5.9",
         "stylus": "~0.54.5",
         "terser": "3.17.0",

packages/index.bzl

@@ -23,6 +23,7 @@ NESTED_PACKAGES = [
     "less",
     "protractor",
     "stylus",
+    "terser",
     "typescript",
 ]
 

packages/terser/BUILD.bazel

@@ -0,0 +1,42 @@
+# Copyright 2017 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("@build_bazel_rules_nodejs//:tools/defaults.bzl", "npm_package")
+
+# Ugly genrule depending on local linux environment to build the README out of skylark doc generation.
+# Only referenced when we do a release.
+# TODO: This ought to be possible with stardoc alone. Need to coordinate with Chris Parsons.
+genrule(
+    name = "generate_README",
+    srcs = [
+        "//packages/terser/docs:index.md",
+        "//packages/terser/docs:install.md",
+    ],
+    outs = ["README.md"],
+    cmd = """cat $(location //packages/terser/docs:install.md) $(location //packages/terser/docs:index.md) | sed 's/^##/\\\n##/' > $@""",
+    visibility = ["//docs:__pkg__"],
+)
+
+npm_package(
+    name = "npm_package",
+    srcs = [
+        "@npm_bazel_terser//:package_contents",
+    ],
+    vendor_external = [
+        "npm_bazel_terser",
+    ],
+    deps = [
+        ":generate_README",
+    ],
+)

packages/terser/docs/BUILD.bazel

@@ -0,0 +1,13 @@
+load("//tools/stardoc:index.bzl", "stardoc")
+
+package(default_visibility = ["//visibility:public"])
+
+exports_files(["install.md"])
+
+stardoc(
+    name = "docs",
+    testonly = True,
+    out = "index.md",
+    input = "@npm_bazel_terser//:index.bzl",
+    deps = ["@npm_bazel_terser//:bzl"],
+)