webpack.config.prod.js

const webpack = require('webpack');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const path = require('path');

module.exports = {
  devtool: 'source-map',
  entry: ['./client/index.js', './client/sass/style.sass'],
  output: {
    path: __dirname + '/public',
    publicPath: '/',
    filename: 'bundle.js'
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        loader: 'babel-loader',
        exclude: /node_modules/,
        options: {
          presets: ['react', 'es2015', 'stage-1']
        },
      },
      {
        test: /\.sass$/,
        use: ExtractTextPlugin.extract({
          fallback: 'style-loader',
          use: ['css-loader', 'postcss-loader', 'sass-loader']
        })
      },
      {
        use: 'file-loader?name=./images/[name].[ext]',
        test: /\.(png|jpg|jpeg|gif|eot|ttf|woff|woff2|svg|svgz)(\?.+)?$/,
        exclude: /node_modules/,
      },
    ]
  },
  plugins: [
    new webpack.optimize.UglifyJsPlugin({
      minimize: true,
      sourceMap: true,
      compress: {
        warnings: false,
        drop_console: true,
        screw_ie8: true
      },
      beautify: false,
      comments: false,
      mangle: {
        except: [
          '$', 'webpackJsonp'
        ],
        screw_ie8: true,
        keep_fnames: true
      },
      output: {
        comments: false,
        screw_ie8: true
      }
    }),
    new webpack.DefinePlugin({
      'process.env': {
        'NODE_ENV': JSON.stringify('production'),
      }
    }),
    new ExtractTextPlugin({ filename: 'css/style.css', allChunks: true }),
  ],
  resolve: {
    extensions: ['.js', '.jsx']
  },
};