karma-commonjs-preprocessor

Preprocessor which enables you to load CoffeScript or Javascript CommonJS Modules on the fly using custom register and loader code.

Installation

The easiest way is to keep karma-commonjs-preprocessor as a devDependency in your package.json.

  "devDependencies":
    "karma": "~0.10"
    "karma-commonjs-preprocessor": "~0.1"

You can simple do it by:

npm install karma-commons-preprocessor --save-dev

Options

registerCmd Allows you to set the name of the function to wrap your module into. Default: "require.register"

isCoffeeScript Allows you to force enable or disable wrapping into coffee-script Format. If its set to false we decide based on the file-extension. Default: false

pathReplace Allows you to set filterer function for module names, for example, change all app/file to file. Default: false

    commonjsPreprocessor:
      options:
        isCoffeeScript: true
        pathReplace: (path) ->
          path.replace(/^app\//, '')

Why not just bundle before running karma?

Creating a single bundle means "recompiling" the bundle anytime any file changes. On big project, this can significantly slow down the development. This plugin processes only files that changed.

How is this different from karma-commonjs?

karma-commonjs is a complete framework handling wrapping, registering and loading all files matching the preprocessor.

The wrapper code of this preprocessor is based on brunch.io and the mechanism adapted from grunt-commonjs-coffee. It only wraps your code into a registering function.

So if you have existing bundles which are build from brunch or do include brunchs require.js directly you can use this preprocessor.

An example karma.conf.coffee could look like this:

module.exports = (config) ->
  config.set
    files: [
      'bower_components/commonjs-require-definition/require.js'
      'src/**/*.coffee'
      'spec/**/*.coffee'
    ]

    preprocessors:
      'src/**/*.coffee': ['commonjs', 'coffee']
      'spec/**/*.coffee': ['coffee']

    plugins: [
      'karma-coffee-preprocessor',
      'karma-commonjs-preprocessor'
    ]

This loads the require.js first and puts require.register into the global namespace. It then packages all coffee Files in the src directoy into commonjs modules and last but not least just executes the specs.

The resulting registering Code looks like this:

window.require.register({'PATH/TO/FILE.JS': function(exports, require, module) {
  FILE_CONTENT
}})

Credits

This plugin is basically a mix between grunt-commonjs-coffee and karma-commonjs.

License

MIT

For more information on Karma see the homepage.