webpack.prod.js

const MiniCssExtractPlugin = require("mini-css-extract-plugin")
const UglifyJsPlugin = require("uglifyjs-webpack-plugin")
const OptimizeCSSAssetsPlugin = require("optimize-css-assets-webpack-plugin")
const merge = require('webpack-merge')
const common = require('./webpack.common.js')

let clientConfig = {
  entry: {
    main: ['./src/index.jsx'],
  },
  mode: 'production',
  devtool: 'source-map',
  // Webpack 4 does not have a CSS minifier, although
  // Webpack 5 will likely come with one
  optimization: {
    minimizer: [
      new UglifyJsPlugin({
        cache: true,
        parallel: true,
        sourceMap: true // set to true if you want JS source maps
      }),
      new OptimizeCSSAssetsPlugin({})
    ]
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: "[name].css",
      chunkFilename: "[id].css"
    })
  ]
}

let serverConfig = {
  entry: {
    server: ['babel-polyfill', './src/server/server.js']
  },
}
module.exports = [merge(common.clientConfig, clientConfig), merge(common.serverConfig, serverConfig)]