webpack.config.js

const webpack = require('webpack');
const path = require('path');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const base = {
  cache: true,
  entry: {
    popup: './src/popup/index.js',
    background: './src/background/index.js'
  },
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: 'js/[name].js'
  },
  module: {
    loaders: [
      {
        test: /\.jsx?$/,
        loader: 'babel-loader',
        query: {
          cacheDirectory: true,
          presets: ['react', 'es2015'],
          plugins: [
            'babel-plugin-lodash',
            'transform-object-rest-spread',
            'transform-async-to-generator',
            'transform-es3-property-literals',
            [
              'transform-runtime',
              {
                helpers: false,
                polyfill: false,
                regenerator: true,
                moduleName: 'babel-runtime'
              }
            ]
          ]
        }
      }
    ]
  },
  plugins: [
    new CopyWebpackPlugin([
      { from: './src/popup/popup.html' },
      { from: './src/manifest.json' },
      { from: './src/images', to: 'images' },
      { from: './src/thirdParty', to: 'thirdParty' }
    ])
  ]
};

module.exports = (env) => {
  env = env || {};
  const isProd = env.production;
  if (isProd) {
    base.plugins.push(
      new webpack.optimize.UglifyJsPlugin({
        compress: { warnings: false }
      })
    );

    base.plugins.push(
      new webpack.DefinePlugin({
        'process.env.NODE_ENV': JSON.stringify('production')
      })
    );
  } else {
    base.devtool = 'inline-source-map';
  }
  return base;
};