webpack.config.babel.js

import CopyWebpackPlugin from 'copy-webpack-plugin';
import webpack from 'webpack';

const NODE_ENV = process.env.NODE_ENV || 'development';
const IS_PRODUCTION = NODE_ENV === 'production';

const config = {
  entry: {
    index: ['./src/index.js'],
  },
  output: {
    path: IS_PRODUCTION ? `${__dirname}/dist` : `${__dirname}/build`,
    filename: '[name].js',
  },
  plugins: [
    new CopyWebpackPlugin([
      { from: './src/_locales', to: '_locales' },
      { from: './src/icon.png' },
      { from: './src/manifest.json' },
    ]),
    new webpack.optimize.UglifyJsPlugin({
      beautify: !IS_PRODUCTION,
      comments: !IS_PRODUCTION,
      compress: IS_PRODUCTION ? { warnings: false } : false,
      mangle: IS_PRODUCTION,
      sourceMap: !IS_PRODUCTION,
    }),
    new webpack.LoaderOptionsPlugin({
      debug: !IS_PRODUCTION,
    }),
  ],
  devtool: IS_PRODUCTION ? 'cheap-source-map' : 'eval',
  module: {
    rules: [
      {
        test: /\.jsx?$/,
        exclude: /node_modules|build|dist/,
        use: [
          {
            loader: 'babel-loader',
            query: {
              cacheDirectory: true,
              cacheIdentifier: true,
            },
          },
        ],
      },
      {
        test: /\.png$/,
        use: [
          {
            loader: 'url-loader',
            query: {
              limit: 10000,
              mimetype: 'image/png',
            },
          },
        ],
      },
    ],
  },
  resolve: {
    extensions: ['.js', '.jsx'],
    modules: ['src', 'node_modules'],
  },
};

module.exports = config;