Karma WebPack 2

This is a fresh Karma webpack loader whose primary aim is to be test driven and simple (currently still in development)

Functionality:

• Webpack configuration specified within Karma config file
• Source map friendly (can be used automatically in results or made available to frameworks)
• Allows specifying other files to Karma outside of your webpack bundle
• Uses in memory filesytem for bundle location (but still allows filesystem caching for loaders like Babel, Opal)
• Commons chunk support

Installation:

npm install karma karma-webpack_2 --save-dev

Configuration:

This is the simplest case:

module.exports = function(config) {
  config.set({
    files: [],
    frameworks: ['jasmine'], // Jasmine not required, use whichever framework you want
    middleware: ['webpack'],
    webpack: {
      entry: ['./entry_point.js']
    }
    ...
  })
}

Since this plugin is feeding output into Karma, it defines the Webpack output config and overwrites whatever you supply (see below re: commons chunk support).

Custom loaders

webpack is the standard webpack configuration object. Here is an example using a different loader:

module.exports = function(config) {
  config.set({
    files: [],
    frameworks: ['jasmine'], // Jasmine not required, use whichever framework you want
    middleware: ['webpack'],
    webpack: {
      entry: ['./entry_point.js'],
      module: {
        loaders: [
          {
            test: /\.rb$/,
            loader: 'opal-webpack'
          }
        ]
      }
    }
    ...
  })
}

Source maps

If source maps are enabled in webpack, they will be served to Karma AND displayed in the results (if something like karma-sourcemap-loader is used). Given there is some overhead in loading source maps in the results, you may only wish to make them available in the browser/launcher you are using and not load them until requested. To do that, use a configuration like this:

module.exports = function(config) {
  config.set({
    files: [],
    frameworks: ['jasmine'], // Jasmine not required, use whichever framework you want
    middleware: ['webpack'],
    webpack: {
      entry: ['./entry_point.js'],
      devtool: 'source-map'
    },
    karmaWebpack: {
      sourceMapResults: false
    }
    ...
  })
}

Commons chunk

If you use the commons chunk Webpack plugin, this tool will find the name of the "vendor" entry point you have declared and have Karma serve that up before your main entry points. Here is an example:

module.exports = function(config) {
  config.set({
    files: [],
    frameworks: ['jasmine'], // Jasmine not required, use whichever framework you want
    middleware: ['webpack'],
    webpack: {
      entry: {
        app: './entry_point.js',
        vendor: ['jquery']
      },
      plugins: [
        new webpack.optimize.CommonsChunkPlugin(/* chunkName= */'vendor', /* filename= */'vendor.bundle.js')
      ]
    }
    ...
  })
}

With this config, vendor.bundle.js will be served followed by app.bundle.js

Limitations:

• Does not rely on webpack dev middleware due to lack of tests for that project. It does however use the memory-fs filesystem
• Webpack config is not automatically read from webpack.config.js for you. You could do that manually in your Karma config for now.

Copyright (c) 2016, BSW Technology Consulting LLC All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

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