webpack.prod.js

const webpack = require('webpack');
const merge = require("webpack-merge");
const CompressionPlugin = require('compression-webpack-plugin');
const common = require('./webpack.common');

module.exports = merge(
    common,
    {
        plugins: [            
            new webpack.DefinePlugin({
                'process.env': {
                    'NODE_ENV': JSON.stringify('production')
                }
            }),
            new webpack.optimize.AggressiveMergingPlugin(),
            new webpack.optimize.OccurrenceOrderPlugin(),
            new webpack.optimize.UglifyJsPlugin({
              mangle: true,
              compress: {
                warnings: false, // Suppress uglification warnings
                pure_getters: true,
                unsafe: true,
                unsafe_comps: true,
                screw_ie8: true,
                conditionals: true,
                unused: true,
                comparisons: true,
                sequences: true,
                dead_code: true,
                evaluate: true,
                if_return: true,
                join_vars: true
              },
              output: {
                comments: false,
              }
            }),
            new CompressionPlugin({
                asset: "[path].gz[query]",
                algorithm: "gzip",
                test: /\.js$|\.css$|\.html$/,
                threshold: 10240,
                minRatio: 0.8
            })
        ]
    }
)