Check, compile, optimize and compress Javascript with Closure-Compiler
This repository tracks issues related to the publication to npmjs.org and associated plugins. Any bugs not related to the plugins themselves should be reported to the main repository.
Closure-compiler requires java to be installed and in the path.
If you are new to Closure-Compiler, make sure to read and understand the compilation levels as the compiler works very differently depending on the compilation level selected.
For help or questions with the compiler, the best resource is Stack Overflow. Posts there are monitored by multiple Closure Compiler team members.
You may also post in the Closure Compiler Discuss Google Group.
Please don't cross post to both Stackoverflow and Closure Compiler Discuss.
The compiler package now includes build tool plugins for Grunt and Gulp.
npm install --save google-closure-compiler
The compiler has a large number of flags. The best documentation for the flags can be found by
running the --help command of the compiler.jar found inside the
node_modules/google-closure-compiler folder:
java -jar compiler.jar --help
Both the grunt and gulp tasks take options objects. The option parameters map directly to the compiler flags without the leading '--' characters.
Values are either strings or booleans. Options which have multiple values can be arrays.
{
js: ['/file-one.js', '/file-two.js'],
compilation_level: 'ADVANCED',
js_output_file: 'out.js',
debug: true
}For advanced usages, the options may be specified as an array of strings. These values include the "--" characters and are directly passed to the compiler in the order specified:
[
'--js', '/file-one.js',
'--js', '/file-two.js',
'--compilation_level', 'ADVANCED',
'--js_output_file', 'out.js',
'--debug'
]When an array of flags is passed, the input files should not be specified via the build tools, but rather as compilation flags directly.
Some shells (particularly windows) try to do expansion on globs rather than passing the string on to the compiler. To prevent this it is necessary to quote certain arguments:
{
js: '"my/quoted/glob/**.js"',
compilation_level: 'ADVANCED',
js_output_file: 'out.js',
debug: true
}Include the plugin in your Gruntfile.js:
require('google-closure-compiler').grunt(grunt);
// The load-grunt-tasks plugin won't automatically load closure-compilerTask targets, files and options may be specified according to the grunt Configuring tasks guide.
require('google-closure-compiler').grunt(grunt);
// Project configuration.
grunt.initConfig({
'closure-compiler': {
my_target: {
files: {
'dest/output.min.js': ['src/js/**/*.js']
},
options: {
compilation_level: 'SIMPLE',
language_in: 'ECMASCRIPT5_STRICT',
create_source_map: 'dest/output.min.js.map',
output_wrapper: '(function(){\n%output%\n}).call(this)\n//# sourceMappingURL=output.min.js.map'
}
}
}
});var compilerPackage = require('google-closure-compiler');
compilerPackage.grunt(grunt);
// Project configuration.
grunt.initConfig({
'closure-compiler': {
my_target: {
files: {
'dest/output.min.js': ['src/js/**/*.js']
},
options: {
js: '/node_modules/google-closure-library/**.js'
externs: compilerPackage.compiler.CONTRIB_PATH + '/externs/jquery-1.9.js',
compilation_level: 'SIMPLE',
manage_closure_dependencies: true,
language_in: 'ECMASCRIPT5_STRICT',
create_source_map: 'dest/output.min.js.map',
output_wrapper: '(function(){\n%output%\n}).call(this)\n//# sourceMappingURL=output.min.js.map'
}
}
}
});// Project configuration.
grunt.initConfig({
'closure-compiler': {
my_target: {
options: {
// When args is present, all other options are ignored
args: [
'--js', '/file-one.js',
'--js', '/file-two.js',
'--compilation_level', 'ADVANCED',
'--js_output_file', 'out.js',
'--debug'
]
}
}
}
});The gulp plugin supports piping multiple files through the compiler.
Options are a direct match to the compiler flags without the leading "--".
var closureCompiler = require('google-closure-compiler').gulp();
gulp.task('js-compile', function () {
return gulp.src('./src/js/**/*.js', {base: './'})
.pipe(closureCompiler({
compilation_level: 'SIMPLE',
warning_level: 'VERBOSE',
language_in: 'ECMASCRIPT6_STRICT',
language_out: 'ECMASCRIPT5_STRICT',
output_wrapper: '(function(){\n%output%\n}).call(this)',
js_output_file: 'output.min.js'
}))
.pipe(gulp.dest('./dist/js'));
});Gulp files are all read into memory, transformed into a JSON stream, and piped through the compiler. With large source sets this may require a large amount of memory.
Closure-compiler can natively expand file globs which will greatly alleviate this issue.
var compilerPackage = require('google-closure-compiler');
var closureCompiler = compilerPackage.gulp();
gulp.task('js-compile', function () {
return closureCompiler({
js: './src/js/**.js',
externs: compilerPackage.compiler.CONTRIB_PATH + '/externs/jquery-1.9.js',
compilation_level: 'SIMPLE',
warning_level: 'VERBOSE',
language_in: 'ECMASCRIPT6_STRICT',
language_out: 'ECMASCRIPT5_STRICT',
output_wrapper: '(function(){\n%output%\n}).call(this)',
js_output_file: 'output.min.js'
})
.pipe(gulp.dest('./dist/js'));
});Gulp attempts to set the base of a glob from the point of the first wildcard. This isn't always
what is desired. Users can specify the { base: 'path' } option to gulp.src calls to override
this behavior.
var closureCompiler = require('google-closure-compiler').gulp();
gulp.task('js-compile', function () {
return closureCompiler([
'--js', '/file-one.js',
'--js', '/file-two.js',
'--compilation_level', 'ADVANCED',
'--js_output_file', 'out.js',
'--debug'
])
.pipe(gulp.dest('./dist/js'));
});By default, the gulp plugin will run the compiler even if no input is streamed in via gulp.src.
To disable this behavior, users can specify a { requireStreamInput: true } argument to skip
compilation if no files are streamed in. This allows interoperation with gulp plugins that signal
through empty streams.
var closureCompiler = require('google-closure-compiler').gulp({
requireStreamInput: true
});
var newer = require('gulp-newer');
gulp.task('js-compile', function () {
return gulp.src('./src/js/**/*.js', {base: './'})
.pipe(newer('./dist/output.min.js'))
.pipe(closureCompiler({
compilation_level: 'ADVANCED',
js_output_file: 'output.min.js'
}))
.pipe(gulp.dest('./dist'));
});The gulp plugin supports gulp sourcemaps.
var closureCompiler = require('google-closure-compiler').gulp();
var sourcemaps = require('gulp-sourcemaps');
gulp.task('js-compile', function () {
return gulp.src('./src/js/**/*.js', {base: './'})
.pipe(sourcemaps.init())
.pipe(closureCompiler({
compilation_level: 'SIMPLE',
warning_level: 'VERBOSE',
language_in: 'ECMASCRIPT6_STRICT',
language_out: 'ECMASCRIPT5_STRICT',
output_wrapper: '(function(){\n%output%\n}).call(this)',
js_output_file: 'output.min.js'
}))
.pipe(souremaps.write('/')) // gulp-sourcemaps automatically adds the sourcemap url comment
.pipe(gulp.dest('./dist/js'));
});A low-level node class is included to facilitate spawning the compiler jar as a process from Node. In addition, it exposes a static property with the path to the compiler jar file.
var ClosureCompiler = require('google-closure-compiler').compiler;
console.log(ClosureCompiler.COMPILER_PATH); // absolute path the compiler jar
console.log(ClosureCompiler.CONTRIB_PATH); // absolute path the contrib folder which contains
var closureCompiler = new ClosureCompiler({
js: 'file-one.js',
compilation_level: 'ADVANCED'
});
var compilerProcess = closureCompiler.run(function(exitCode, stdOut, stdErr) {
//compilation complete
});Copyright 2015 The Closure Compiler Authors
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.
Closure Compiler release notes can be found on the main repository wiki.
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