gulp-closure-compiler

Gulp plugin for Google Closure Compiler

Issues with the output or Java should be reported on the Closure Compiler issue tracker.

Install

npm install --save-dev gulp-closure-compiler

Example

Simple optimizations

Simple optimizations for classic minifying.

var gulp = require('gulp');
var closureCompiler = require('gulp-closure-compiler');

gulp.task('default', function() {
  return gulp.src('src/*.js')
    .pipe(closureCompiler('build.js'))
    .pipe(gulp.dest('dist'));
});

Advanced optimizations

Advanced optimizations is much more aggressive. It's aimed for libraries like Closure Library.

var gulp = require('gulp');
var closureCompiler = require('gulp-closure-compiler');

gulp.task('default', function() {
  return gulp.src('src/*.js')
    .pipe(closureCompiler({
      // compilerPath is optional, since google-closure-compiler is a dependency
      // compilerPath: 'bower_components/closure-compiler/lib/vendor/compiler.jar', 
      fileName: 'build.js',
      compilerFlags: {
        closure_entry_point: 'app.main',
        compilation_level: 'ADVANCED_OPTIMIZATIONS',
        define: [
          "goog.DEBUG=false"
        ],
        externs: [
          'bower_components/este-library/externs/react.js'
        ],
        extra_annotation_name: 'jsx',
        only_closure_dependencies: true,
        // .call is super important, otherwise Closure Library will not work in strict mode.
        output_wrapper: '(function(){%output%}).call(window);',
        warning_level: 'VERBOSE'
      }
    }))
    .pipe(gulp.dest('dist'));
});

Compiling with Google Closure Library

The current version of the compiler doesn't need a deps file as it used to. Now you need to supply the directories where your dependencies are defined (via goog.provide).

var gulp = require('gulp');
var closureCompiler = require('gulp-closure-compiler');

gulp.task('default', function() {
  return gulp.src(['main.js', 'src/**/*.js', 'bower_components/closure-library/closure/goog/**/*.js'])
    .pipe(closureCompiler({
      compilerPath: 'bower_components/closure-compiler/compiler.jar',
      fileName: 'build.js',
      compilerFlags: {
        closure_entry_point: 'app.main',
        compilation_level: 'ADVANCED_OPTIMIZATIONS',
        only_closure_dependencies: true,
        warning_level: 'VERBOSE'
      }
    }))
    .pipe(gulp.dest('dist'));
});

API

closureCompiler(options)

options

fileName

Type: String
Required

Generated file name.

compilerPath

Type: String

Path to compiler.jar

compilerFlags

Type: Object

Closure compiler flags.

tieredCompilation

Type: Boolean

Tiered compilation enhances the speed of compilation. It's supported everywhere since Java 1.7+, but requires the installation of a JDK.

maxBuffer

Type: Number

If the buffer returned by closure compiler is more than 1000kb, you will get an error saying "maxBuffer exceeded". To prevent this, you can set the maxBuffer to the preffered size you want (in kb).

continueWithWarnings

Type: boolean

Ignore the warnings and continue with the compiler. This adds flexiblity to some projects that can't work around certain warnings. Default value is false.

How to download Closure Compiler

Note: This step isn't required any more as of v0.4.0!

Use Bower.

{
  "name": "foo",
  "version": "0.0.0",
  "dependencies": {
    "closure-compiler": "http://dl.google.com/closure-compiler/compiler-latest.zip"
  }
}

Implementation notes

• Closure compiler supports pipes, but not correctly (issue).
• You don't need closurebuilder.py script, compiler knows how to resolve dependencies.
• Java 1.7+ is required.

License

MIT © Daniel Steigerwald