text: const webpack = require('webpack');
  const merge = require('webpack-merge');
  const UglifyJSPlugin = require('uglifyjs-webpack-plugin');
  const ExtractTextPlugin = require('extract-text-webpack-plugin');
  const common = require('./webpack.common.js');
  module.exports = merge(common, {
      devtool: 'source-map',
      plugins: [
          new UglifyJSPlugin({
              sourceMap: true,
              parallel: 4
          }),
          new webpack.DefinePlugin({
              'process.env.NODE_ENV': JSON.stringify('production')
          }),
          new ExtractTextPlugin({
              filename: "[name].[contenthash].css"
          })
      ]
  });
  