webpack.config.prod.js

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

module.exports = {
  devtool: 'cheap-module-source-map',
  entry: [
    './src/index'
  ],
  output: {
    path: path.join(__dirname, 'static'),
    filename: 'bundle.js',
    publicPath: 'static',
  },
  plugins: [
    new webpack.optimize.OccurenceOrderPlugin(),
    new webpack.optimize.UglifyJsPlugin({
      compressor: {
        warnings: false
      }
    }),
    new webpack.DefinePlugin({
      "process.env": {
         NODE_ENV: JSON.stringify("production") 
       }
    }),
    new ExtractTextPlugin("style.css", {
        allChunks: true
    })
  ],
  module: {
    loaders: [
      {
        test: /\.js$/,
        exclude: [/node_modules/, /styles/],
        loaders: ['babel'],
        include: path.join(__dirname, 'src')
      },
      {
        test: /\.scss$/,
        loader: ExtractTextPlugin.extract('style', 'css!postcss!sass')
      },
      {
        test: /\.(eot|woff|woff2|ttf|svg|png|jpg)$/,
        loader: 'url-loader?limit=30000&name=[name]-[hash].[ext]'
      },
    ]
  },
  postcss: function () {
    return [precss, autoprefixer];
  },
};