webpack.config.dev.js

const webpack = require('webpack')

module.exports = {
  resolve: {
    extensions: ['', '.js'],
  },

  module: {
    noParse: [
      /\/sinon.js/,
    ],
    preLoaders: [ // << add subject as webpack's preloader
      {
        test: /\.js$/,
        // exclude this dirs from coverage
        exclude: /(test|node_modules|bower_components)\//,
        loader: 'isparta-instrumenter-loader',
      },
    ],
    loaders: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        loader: 'babel',
      },
      {
        test: /\.json$/,
        loader: 'json',
      },
    ],
  },

  node: {
    fs: 'empty',
  },

  plugins: [
    new webpack.NormalModuleReplacementPlugin(
      /^sinon$/,
      `${__dirname}/node_modules/sinon/pkg/sinon.js`
    ),
  ],

  stats: {
    colors: true,
    reasons: true,
  },

  progress: true,
}