Compiles ECMAScript 6 (harmony) files, optionally merging and generating source maps
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.


Grunt task that uses google traceur compiler to build ECMAScript 6 (harmony) projects, optionally merging and generating source maps.

Getting Started

npm install grunt-traceur-build --save-dev

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:


The "traceur_build" task


In your project's Gruntfile, add a section named traceur_build to the data object passed into grunt.initConfig(). Eg:

  traceur_build: {
    options: {
      wrap: { // wraps the built files into a anonymous function that has
              // a binds 'expression' to 'param'. In the example below:
              // (function(exports) {
              //  /* code */
              // })(window.mymodule = {});
        param: 'exports',
        expression: 'window.mymodule = {}'
      sourceMaps: true,
      deferredFunctions: true
    project: {
      cwd: 'src',
      src: '**/*.js',
      dest: './build/build.js'


Almost all options are passed to the traceur compiler directly, see the section below for the default values.

Keep in mind that when a javascript file(any name ending with .js) is specified as the destination, the task will build and combine everything into one file, taking into consideration 'import' statements to resolve dependencies and put the files in the correct order.

It will by default generate source maps for debugging(as far as I know only google chrome and node-inspector support this feature. In node.js, stack traces will display the original filenames/location if you install the node-source-map-support package

Usage Examples

Default Options

  traceur_build: {
    options: {
      debug: false,
      sourceMaps: true,
      freeVariableChecker: true,
      validate: false,
      strictSemicolons: false,
      unstarredGenerators: false,
      ignoreNolint: false,
      arrayComprehension: true,
      arrowFunctions: true,
      classes: true,
      defaultParameters: true,
      destructuring: true,
      forOf: true,
      propertyMethods: true,
      propertyNameShorthand: true,
      templateLiterals: true,
      restParameters: true,
      spread: true,
      generatorComprehension: true,
      generators: true,
      modules: true,
      blockBinding: false,
      privateNameSyntax: false,
      privateNames: false,
      cascadeExpression: false,
      trapMemberLookup: false,
      deferredFunctions: false,
      propertyOptionalComma: false,
      types: false
    files: {
      'dest/default_options': ['src/testing', 'src/123'],