node package manager
Stop wasting time. Easily manage code sharing in your team. Create a free org »


Grunt Closure Tools

Google Closure Tools for grunt:

  • Compiler Compile your JS code using the powerful google closure compiler
  • Builder Concatenate your JS codebase to a single file, optionally also compile it
  • DepsWriter Calculate dependencies of your JS files and generate deps.js

Build Status

Getting Started

Install the module with: npm install grunt-closure-tools

npm install grunt-closure-tools --save-dev

Then register the task by adding the following line to your grunt.js:


Grunt 0.3.x compatibility

Migration Guide from 0.3.x grunt config to 0.4.x

To get a grunt 0.3.x. compatible version please install with:

npm install grunt-closure-tools@0.6.13 --save-dev

The Grunt 0.3.x repository can be found frozen in this branch.


All three tasks (compiler, builder and depswriter) are multitasks, so you can specify several targets depending on the complexity of your project.

Closure Compiler

The Closure Compiler task has two requirements.

  1. compilerFile The location of the compiler. Find the latest compiler.jar file here.
  2. src The js files you want to compile.

You can fully configure how the compiler will behave, by setting directives in the options. Every key will be used as a directive for the compiler.

You can use grunt file syntax (<config:...> or path/**/*.js) for the js directive and for declaring externs, set in options.externs.

Read more about the closure compiler here.

There is an NPM package that will install the closure compiler .jar, check out the superstartup-closure-compiler repository, the README there will give you examples of how to plug it to this package.

Sample Config for The Closure Compiler

closureCompiler:  {
  options: {
    // [REQUIRED] Path to closure compiler 
    compilerFile: 'path/to/closure/compiler.jar',
    // [OPTIONAL] set to true if you want to check if files were modified 
    // before starting compilation (can save some time in large sourcebases) 
    checkModified: true,
    // [OPTIONAL] Set Closure Compiler Directives here 
    compilerOpts: {
       * Keys will be used as directives for the compiler
       * values can be strings or arrays.
       * If no value is required use null
       * The directive 'externs' is treated as a special case
       * allowing a grunt file syntax (<config:...>, *)
       * Following are some directive samples...
       compilation_level: 'ADVANCED_OPTIMIZATIONS',
       externs: ['path/to/file.js', '/source/**/*.js'],
       define: ["'goog.DEBUG=false'"],
       warning_level: 'verbose',
       jscomp_off: ['checkTypes', 'fileoverviewTags'],
       summary_detail_level: 3,
       output_wrapper: '"(function(){%output%}).call(this);"'
    // [OPTIONAL] Set exec method options 
    execOpts: {
        * Set maxBuffer if you got message "Error: maxBuffer exceeded."
        * Node default: 200*1024
       maxBuffer: 999999 * 1024
    // [OPTIONAL] Java VM optimization options 
    // see 
    // Setting one of these to 'true' is strongly recommended, 
    // and can reduce compile times by 50-80% depending on compilation size 
    // and hardware. 
    // On server-class hardware, such as with Github's Travis hook, 
    // TieredCompilation should be used; on standard developer hardware, 
    // d32 may be better. Set as appropriate for your environment. 
    // Default for both is 'false'; do not set both to 'true'. 
    d32: true, // will use 'java -client -d32 -jar compiler.jar' 
    TieredCompilation: true // will use 'java -server -XX:+TieredCompilation -jar compiler.jar' 
  // any name that describes your task 
  targetName: {
     *[OPTIONAL] Here you can add new or override previous option of the Closure Compiler Directives.
     * IMPORTANT! The feature is enabled as a temporary solution to [#738](
     * As soon as issue will be fixed this feature will be removed.
    TEMPcompilerOpts: {
    // [OPTIONAL] Target files to compile. Can be a string, an array of strings 
    // or grunt file syntax (<config:...>, *) 
    src: 'path/to/file.js',
    // [OPTIONAL] set an output file 
    dest: 'path/to/compiled_file.js'

Closure compiler is typically used to produce a single output file out of multiple input files. For such scenario you specify src and dest properties as in the sample above. Grunt, however, has richer support for specifying source-destination mappings and you can leverage it for accomplishing other compilation scenarios, e.g. compiling a single output file out of each source file as demonstrates the sample below. To support also generation of source maps for this case you can specify create_source_map in compilerOpts with value set to null. This causes passing the dest filename with suffix .map to closure compiler's create_source_map parameter (this behavior is valid only when source-destination file mapping is specified for processing).

closureCompiler: {
    options: {
        // most options here omitted for brevity 
        compilerOpts: {
            // most options here omitted for brevity 
            create_source_map: null,
             * When 'create_source_map' with value set to null is defined here AND the dest file is specified in
             * the form of source-destination file mapping, the name of dest file extended with '.map' is passed
             * as value of parameter 'create_source_map' to the compiler to enable a source map file per output file.
             * E.g. for
             *  files: [
             * {src: 'lib/a.js', dest: 'build/a.min.js'},
             * {src: 'lib/b.js', dest: 'build/b.min.js'},
             *   ],
             * the value of 'create_source_map' would be 'build/' for the first mapping
             * and 'build/' for the second one.
    minify: {
         * Following sample uses dynamically created mappings, where src array of globs is evaluated
         * and dest file is constructed for each source file by replacing its extension with '.min.js'.
        files: [
                expand: true,
                src: ['**/*.js', '!**/*.min.js'],
                ext: '.min.js'

Closure Builder

The Closure Builder task has 3 required directives:

  1. A way to find the file. One of the following two directives are required:
* **`closureLibraryPath`** A path to the Google Closure Library. From there we can infer the location of the file
* **`builder`** Directly reference the file
  1. An input method must be defined. One of the following two directives is required:
* **`inputs`** String, array or grunt file syntax to define build targets
* **`namespaces`** String or array to define namespaces to build
  1. The root targets of the closureBuilder. These are defined in the:
* **`src`** option of each target. Can be string or array.

The builder has the ability to compile on-the-fly the built files. To enable this option you need to set the option compile to boolean true and then set the location of the compiler.jar file via the compiler directive.

You can set all the compiler directives in the compiler_options object. The js directive is no longer required, as the builder takes care of that. The compiler directives follow the same logic as the ones in the Closure Compiler multitask described above.

Read more about the closure builder in this link.

Sample Config for The Closure Builder

closureBuilder:  {
  options: {
    // [REQUIRED] To find the builder executable we need either the path to 
    //    closure library or directly the filepath to the builder: 
    closureLibraryPath: 'path/to/closure-library', // path to closure library 
    // [OPTIONAL] You can define an alternative path of the builder. 
    //    If set it trumps 'closureLibraryPath' which will not be required. 
    builder: 'path/to/',
    // [REQUIRED] One of the two following options is required: 
    inputs: 'string|Array', // input files (can just be the entry point) 
    namespaces: 'string|Array', // namespaces 
    // [OPTIONAL] Define the Python binary: 
    pythonBinary: '/path/to/binary/python/',
    // [OPTIONAL] The location of the compiler.jar 
    // This is required if you set the option "compile" to true. 
    compilerFile: 'path/to/compiler.jar',
    // [OPTIONAL] output_mode can be 'list', 'script' or 'compiled'. 
    //    If compile is set to true, 'compiled' mode is enforced. 
    //    Default is 'script'. 
    output_mode: '',
    // [OPTIONAL] if we want builder to perform compile 
    compile: false, // boolean 
    compilerOpts: {
      * Go wild here...
      * any key will be used as an option for the compiler
      * value can be a string or an array
      * If no value is required use null
    // [OPTIONAL] Set exec method options 
    execOpts: {
        * Set maxBuffer if you got message "Error: maxBuffer exceeded."
        * Node default: 200*1024
       maxBuffer: 999999 * 1024
  // any name that describes your operation 
  targetName: {
    // [REQUIRED] paths to be traversed to build the dependencies 
    src: 'string|Array',
    // [OPTIONAL] if not set, will output to stdout 
    dest: ''

Closure DepsWriter

The Closure DepsWriter task has 1 required directive:

  1. A way to find the file. One of the following two directives is required:
* **`closureLibraryPath`** A path to the Google Closure Library. From there we can infer the location of the file
* **`depswriter`** Directly reference the file

Read more about depswriter here.

Sample Config for The Closure DepsWriter

closureDepsWriter: {
  options: {
    // [REQUIRED] To find the depswriter executable we need either the path to 
    //    closure library or the depswriter executable full path: 
    closureLibraryPath: 'path/to/closure-library',
    // [OPTIONAL] Define the full path to the executable directly. 
    //    If set it trumps 'closureLibraryPath' which will not be required. 
    depswriter: 'path/to/', // filepath to depswriter 
    // [OPTIONAL] Root directory to scan. Can be string or array 
    root: ['source/ss', 'source/closure-library', 'source/showcase'],
    // [OPTIONAL] Root with prefix takes a pair of strings separated with a space, 
    //    so proper way to use it is to suround with quotes. 
    //    can be a string or array 
    root_with_prefix: '"source/ss ../../ss"',
    // [OPTIONAL] string or array 
    path_with_depspath: ''
   // any name that describes your operation 
  targetName: {
    // [OPTIONAL] Set file targets. Can be a string, array or 
    //    grunt file syntax (<config:...> or *) 
    src: 'path/to/awesome.js',
    // [OPTIONAL] If not set, will output to stdout 
    dest: ''

Release History

  • v1.0.0, 26 Jul 2017
  • v0.9.9, 08 Jun 2015
  • v0.9.8, 16 Jan 2015
    • Upgraded to task-closure-tools v0.1.9, better handling for cases where an empty source is provided. @betaorbust.
  • v0.9.7, 08 Jul 2014
    • Upgraded to task-closure-tools v0.1.7, new option pythonBinary defines the Python binary.
  • v0.9.6, 12 Mar 2014
    • Added test suite
    • Support for ClosureBuilder new JVM flags Thanks @robertdimarco
  • v0.9.4, 07 Mar 2014
    • Properly escapes compiler filename, will fix cases where spaces existed in the filename. Thanks @tgirardi
  • v0.9.3, 22 Feb 2014
    • Added compile optimization switches 50%+ gains! Thank you @probins
    • Updated Closure Compiler's zip file link on readme, thank you @ggundersen
    • Moved repository to thanpolas account
  • v0.9.2, 13 Jan 2014
    • Fixed bug that optExecOptions was passed only to first file in list by @stforek.
  • v0.9.0, 16 Dec 2013
    • No changes have been made, this is a stub version to indicate the change in the location of the core library, it has now been moved to its own repo and nmp package task-closure-tools.
  • v0.8.7, 12 Dec 2013
    • Added option to produce multiple SourceMap files when multiple source-dest compile targets are defined, thanks @fhurta
  • v0.8.4, 31 Oct 2013
    • Minor change in callback signature of helper 'executeCommand'
  • v0.8.3, 22 Apr 2013
    • If checkModified: true issue fixed correctly.
  • v0.8.2, 22 Apr 2013
    • If checkModified: true and the files not chaged the task does not fail.
  • v0.8.1, 19 Apr 2013
    • Added temporary feature to enable merging and overriding of the compilerOpts in the closureCompiler targets. Feature will be available until #738 will be fixed.
    • Added new option: execOpts. It allow to pass custom options to exec method.
    • Bug fixes 1.
  • v0.8.0, 28 Mar 2013
    • Changed internal API, it's a breaking change the package is required as an npm packaged.
    • Colors changed in build stats output.
  • v0.7.7, 19 Mar 2013
    • Removed the compiling time optimization for now, it fails the travis tests.
  • v0.7.6, 19 Mar 2013
    • helpers.makeParam() - if param is an array, makeParam() should return a flat array after expanding its items with grunt.file.expand and not an array of arrays. By @centi #22
    • Added two options on the compile command to speed up compiling time. Tip from @igorminar on this commit.
    • Moved repository to the closureplease organization. the full changelog.


Copyright ©2015 Thanasis Polychronakis Licensed under the MIT license. alpha

Bitdeli Badge