webpack.config.prod.js

const path = require('path');
const webpack = require('webpack');
const CleanWebpackPlugin = require('clean-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const precss = require('precss');
const autoprefixer = require('autoprefixer');



module.exports = {
  entry: path.resolve(__dirname, 'app/index'),
  devServer: {
    historyApiFallback: true,
    outputPath: path.join(__dirname, 'build'),
  },
  resolve: {
    extensions: ['', '.js', '.jsx'],
  },
  output: {
    path: path.resolve(__dirname, 'build/js'),
    publicPath: '/js/',
    filename: 'bundle.js',
  },
  plugins: [
    new CleanWebpackPlugin(['build']),
    new webpack.DefinePlugin({
        'process.env':{
          'NODE_ENV': JSON.stringify('production')
        }
      }),
    new webpack.optimize.UglifyJsPlugin({
      minimize: true,      
      compress:{
        warnings: true,
        }
      }),
    new CopyWebpackPlugin([
      {
        context: path.resolve(__dirname, 'app/static'),
        from: '**/*',
        to: path.resolve(__dirname, 'build'),
      },
    ]),
  ],
  module: {
    loaders: [
      {
        test: /\.jsx?$/,
        exclude: /(node_modules|bower_components)/,
        loaders: ['babel'],
      },
      {
        test: /\.css$/,
        loader: 'style-loader!css-loader!postcss-loader',
      },
    ],
  },
  postcss: () => [
    precss,
    autoprefixer,
  ],
};