Production ready webpack config for images, es2015/babel/react js/jsx, and sass/scss

webpack.config.js

var autoprefixer = require('autoprefixer');
const webpack = require('webpack');

module.exports = {
  output: {
    path: __dirname + "/dist",
    filename: "bundle.js"
  },
  module: {
    loaders: [
      {
        test: /\.(jpe?g|png|gif|svg)$/i,
        loaders: [
          'file?hash=sha512&digest=hex&name=[hash].[ext]',
          'image-webpack?bypassOnDebug&optimizationLevel=7&interlaced=false'
        ]
      },
      { 
        test: /\.css$/, 
        loader: "style!css?sourceMap!postcss-loader" 
      },
      {
        test: /\.scss$/,
        loaders: ["style", "css", "sass", "postcss-loader"]
      },
      {
        test: /\.jsx?$/,
        exclude: /(node_modules|bower_components)/,
        loader: 'babel',
        query: {
          presets: ['es2015', 'react']
        }
      }
    ]
  },
  postcss: [ autoprefixer({ browsers: ['last 2 versions'] }) ],
  plugins: [
    new webpack.DefinePlugin({
      'process.env': {
        'NODE_ENV': JSON.stringify('production')
      }
    }),
    new webpack.optimize.UglifyJsPlugin({
      minimize: true,
      compress: {
        unused: true,
        dead_code: true,
        warnings: false,
        screw_ie8: true
      },
      compress: {
        warnings: false
      }
    })
  ],
};