(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';
@@ -194,18 +195,20 @@ 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

@@ -13,6 +13,8 @@ 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';
 declare module 'rollup-plugin-terser';

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/integration/fixtures/build-withClosure/package.json

@@ -0,0 +1,7 @@
+{
+  "scripts": {
+    "build": "tsdx build"
+  },
+  "name": "build-withclosure",
+  "license": "MIT"
+}

test/integration/fixtures/build-withClosure/src/index.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/integration/fixtures/build-withClosure/tsconfig.json

@@ -0,0 +1,28 @@
+{
+  "compilerOptions": {
+    "module": "ESNext",
+    "lib": ["dom", "esnext"],
+    "declaration": true,
+    "sourceMap": true,
+    "rootDir": "./src",
+    "strict": true,
+    "noImplicitAny": true,
+    "strictNullChecks": true,
+    "strictFunctionTypes": true,
+    "strictPropertyInitialization": true,
+    "noImplicitThis": true,
+    "alwaysStrict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "moduleResolution": "node",
+    "baseUrl": "./",
+    "paths": {
+      "*": ["src/*", "node_modules/*"]
+    },
+    "jsx": "react",
+    "esModuleInterop": true
+  },
+  "include": ["src", "types"],
+}

test/integration/fixtures/build-withClosure/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/integration/tsdx-build-withClosure.test.ts

@@ -0,0 +1,76 @@
+import * as shell from 'shelljs';
+import * as util from '../utils/fixture';
+import { grep } from '../utils/shell';
+
+shell.config.silent = false;
+
+const testDir = 'integration';
+const fixtureName = 'build-withClosure';
+const stageName = `stage-integration-${fixtureName}`;
+
+describe('integration :: tsdx build :: --closureCompiler', () => {
+  beforeAll(() => {
+    util.teardownStage(stageName);
+  });
+  beforeEach(() => {
+    util.setupStageWithFixture(testDir, stageName, fixtureName);
+  });
+
+  it('should minify bundle with default options', () => {
+    let output = shell.exec('node ../dist/index.js build --closureCompiler');
+    expect(output.code).toBe(0);
+
+    expect(shell.test('-f', 'dist/index.js')).toBeTruthy();
+    expect(shell.test('-f', 'dist/index.d.ts')).toBeTruthy();
+    expect(
+      shell.test('-f', 'dist/build-withclosure.cjs.development.js')
+    ).toBeTruthy();
+    expect(
+      shell.test('-f', 'dist/build-withclosure.cjs.production.min.js')
+    ).toBeTruthy();
+    expect(shell.test('-f', 'dist/build-withclosure.esm.js')).toBeTruthy();
+
+    const lib = require(`../../${stageName}/dist`);
+    expect(lib.signature).toBe('bar 0');
+
+    // with SIMPLE optimization level minified bundle should contain
+    // simplePattern 'exports.signature=signature'
+    expect(
+      grep(/exports\.signature=signature/, [
+        'dist/build-withclosure.cjs.production.min.js',
+      ])
+    ).toBeTruthy();
+  });
+
+  it('should minify bundle with advanced options', () => {
+    shell.mv('-f', 'tsdx.config.closure-advanced.js', 'tsdx.config.js');
+
+    const 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', 'dist/build-withclosure.cjs.development.js')
+    ).toBeTruthy();
+    expect(
+      shell.test('-f', 'dist/build-withclosure.cjs.production.min.js')
+    ).toBeTruthy();
+    expect(shell.test('-f', 'dist/build-withclosure.esm.js')).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(
+      grep(/exports\.a="bar 0"/, [
+        'dist/build-withclosure.cjs.production.min.js',
+      ])
+    ).toBeTruthy();
+  });
+
+  afterEach(() => {
+    util.teardownStage(stageName);
+  });
+});