(feat): closure compiler for minification

README.md

@@ -341,6 +341,8 @@ export interface TsdxOptions {
   writeMeta?: boolean;
   // Only transpile, do not type check (makes compilation faster)
   transpileOnly?: boolean;
+  // EXPERIMENTAL: Use closure compiler to minify production bundle instead of terser
+  closureCompiler?: boolean;
 }
 ```
 

package.json

@@ -35,6 +35,7 @@
     "templates"
   ],
   "dependencies": {
+    "@ampproject/rollup-plugin-closure-compiler": "^0.22.2",
     "@babel/core": "^7.4.4",
     "@babel/helper-module-imports": "^7.0.0",
     "@babel/plugin-proposal-class-properties": "^7.4.4",

src/createRollupConfig.ts

@@ -2,6 +2,7 @@ import { safeVariableName, safePackageName, external } from './utils';
 import { paths } from './constants';
 import { RollupOptions } from 'rollup';
 import { terser } from 'rollup-plugin-terser';
+import closureCompiler from '@ampproject/rollup-plugin-closure-compiler';
 import { DEFAULT_EXTENSIONS } from '@babel/core';
 // import babel from 'rollup-plugin-babel';
 import commonjs from '@rollup/plugin-commonjs';
@@ -195,18 +196,20 @@ export async function createRollupConfig(
       //   printInfo: false,
       // }),
       shouldMinify &&
-        terser({
-          sourcemap: true,
-          output: { comments: false },
-          compress: {
-            keep_infinity: true,
-            pure_getters: true,
-            passes: 10,
-          },
-          ecma: 5,
-          toplevel: opts.format === 'cjs',
-          warnings: true,
-        }),
+        (opts.closureCompiler
+          ? closureCompiler()
+          : terser({
+              sourcemap: true,
+              output: { comments: false },
+              compress: {
+                keep_infinity: true,
+                pure_getters: true,
+                passes: 10,
+              },
+              ecma: 5,
+              toplevel: opts.format === 'cjs',
+              warnings: true,
+            })),
     ],
   };
 }

src/env.d.ts

@@ -14,6 +14,7 @@ declare module '@babel/core' {
 }
 
 // Rollup plugins
+declare module '@ampproject/rollup-plugin-closure-compiler';
 declare module '@jaredpalmer/rollup-plugin-preserve-shebang';
 declare module 'rollup-plugin-babel';
 declare module 'rollup-plugin-size-snapshot';

src/index.ts

@@ -380,6 +380,11 @@ prog
   .example('build --tsconfig ./tsconfig.foo.json')
   .option('--transpileOnly', 'Skip type checking')
   .example('build --transpileOnly')
+  .option(
+    '--closureCompiler',
+    'EXPERIMENTAL: Use closure compiler to minify production bundle instead of terser'
+  )
+  .example('build --closureCompiler')
   .option(
     '--extractErrors',
     'Extract errors to ./errors/codes.json and provide a url for decoding.'

src/types.ts

@@ -47,6 +47,8 @@ export interface TsdxOptions extends SharedOpts {
   writeMeta?: boolean;
   // Only transpile, do not type check (makes compilation faster)
   transpileOnly?: boolean;
+  // EXPERIMENTAL: Use closure compiler to minify production bundle instead of terser
+  closureCompiler?: boolean;
 }
 
 export interface PackageJson {

test/fixtures/build-withConfig/src/closure.ts

@@ -0,0 +1,11 @@
+const split = (str: string) => str.split('');
+
+const sum = (a: number, b: number) => {
+  return a + b;
+};
+
+const bar = split('bar');
+
+// this line gets minified differently with
+// Terser vs. Closure vs. Closure ADVANCED_OPTIMIZATIONS
+export const signature = `${split('bar').join('')} ${sum(bar.length, -3)}`;

test/fixtures/build-withConfig/src/index.ts

@@ -1,8 +1,4 @@
-import invariant from 'tiny-invariant';
-import warning from 'tiny-warning';
-invariant(true, 'error occurred! o no');
-warning(false, 'warning - water is wet');
-export { foo } from './foo';
+export { signature } from './closure';
 
 export const sum = (a: number, b: number) => {
   if ('development' === process.env.NODE_ENV) {

test/fixtures/build-withConfig/tsdx.config.closure-advanced.js

@@ -0,0 +1,19 @@
+const closureCompiler = require('@ampproject/rollup-plugin-closure-compiler');
+
+const closureCompilerPlugin = closureCompiler({
+  compilation_level: 'ADVANCED_OPTIMIZATIONS',
+});
+
+module.exports = {
+  rollup(config) {
+    config.plugins = config.plugins.map(plugin => {
+      // override closure compiler plugin's default config
+      if (plugin && plugin.name === closureCompilerPlugin.name) {
+        return closureCompilerPlugin;
+      }
+      return plugin;
+    });
+
+    return config;
+  },
+};

test/fixtures/util.js

@@ -4,6 +4,17 @@ const rootDir = process.cwd();
 
 shell.config.silent = true;
 
+// shelljs.grep wrapper
+// @param {string|RegExp} pattern
+// @param {string} fileName
+// @returns {boolean} true if pattern has matches in file
+function grep(pattern, fileName) {
+  const output = shell.grep(pattern, fileName);
+  // output.code is always 0 regardless of matched/unmatched patterns
+  // so need to test output.stdout
+  return Boolean(output.stdout.match(pattern));
+}
+
 module.exports = {
   setupStageWithFixture: (stageName, fixtureName) => {
     const stagePath = path.join(rootDir, stageName);
@@ -22,5 +33,6 @@ module.exports = {
     shell.rm('-rf', path.join(rootDir, stageName));
   },
 
+  grep,
   rootDir,
 };

test/tests/tsdx-build-closure-compiler.test.js

@@ -0,0 +1,70 @@
+/**
+ * @jest-environment node
+ */
+
+const shell = require('shelljs');
+const util = require('../fixtures/util');
+
+shell.config.silent = false;
+
+const stageName = 'stage-build-closure-compiler';
+
+const cjsBundleDev = 'dist/build-withconfig.cjs.development.js';
+const cjsBundleProd = 'dist/build-withconfig.cjs.production.min.js';
+const esmBundle = 'dist/build-withconfig.esm.js';
+
+const simplePattern = /exports\.signature=signature/;
+const advancedPattern = /exports\.a="bar 0"/;
+
+describe('tsdx build with closure compiler', () => {
+  beforeAll(() => {
+    util.teardownStage(stageName);
+  });
+
+  it('should minify bundle with default options', () => {
+    util.setupStageWithFixture(stageName, 'build-withConfig');
+
+    let output = shell.exec('node ../dist/index.js build --closureCompiler');
+    expect(output.code).toBe(0);
+
+    expect(shell.test('-f', 'dist/index.js')).toBeTruthy();
+    expect(shell.test('-f', 'dist/index.d.ts')).toBeTruthy();
+    expect(shell.test('-f', cjsBundleDev)).toBeTruthy();
+    expect(shell.test('-f', cjsBundleProd)).toBeTruthy();
+    expect(shell.test('-f', esmBundle)).toBeTruthy();
+
+    const lib = require(`../../${stageName}/dist`);
+    expect(lib.signature).toBe('bar 0');
+
+    // with SIMPLE optimization level minified bundle should contain
+    // simplePattern 'exports.signature=signature'
+    expect(util.grep(simplePattern, cjsBundleProd)).toBeTruthy();
+    expect(util.grep(advancedPattern, cjsBundleProd)).toBeFalsy();
+  });
+
+  it('should minify bundle with advanced options', () => {
+    util.setupStageWithFixture(stageName, 'build-withConfig');
+    shell.mv('-f', 'tsdx.config.closure-advanced.js', 'tsdx.config.js');
+
+    let output = shell.exec('node ../dist/index.js build --closureCompiler');
+    expect(output.code).toBe(0);
+
+    expect(shell.test('-f', 'dist/index.js')).toBeTruthy();
+    expect(shell.test('-f', 'dist/index.d.ts')).toBeTruthy();
+    expect(shell.test('-f', cjsBundleDev)).toBeTruthy();
+    expect(shell.test('-f', cjsBundleProd)).toBeTruthy();
+    expect(shell.test('-f', esmBundle)).toBeTruthy();
+
+    const lib = require(`../../${stageName}/dist`);
+    expect(lib.signature).toBe('bar 0');
+
+    // with ADVANCED optimization level minified bundle should contain
+    // advancedPattern 'exports.a="bar 0"'
+    expect(util.grep(simplePattern, cjsBundleProd)).toBeFalsy();
+    expect(util.grep(advancedPattern, cjsBundleProd)).toBeTruthy();
+  });
+
+  afterEach(() => {
+    util.teardownStage(stageName);
+  });
+});