webpack.config.prod.js

const path = require('path');
const webpack = require('webpack');
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
const CompressionPlugin = require('compression-webpack-plugin');
const HTMLWebpackPlugin = require('html-webpack-plugin');

module.exports = {
  mode: 'production',
  entry: ['./index.js'],
  context: __dirname,
  devtool: 'source-map',
  output: {
    path: path.join(__dirname, 'dist'),
    filename: 'bundle.js',
    publicPath: '/',
  },
  resolve: {
    extensions: ['*', '.scss', '.js'],
    modules: ['node_modules'],
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /(node_modules)/,
        use: {
          loader: 'babel-loader?cacheDirectory=true',
        },
      },
      {
        test: /\.(scss|css)$/,
        use: ['style-loader', 'css-loader', 'sass-loader'],
      },
    ],
  },
  plugins: [
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify('production'),
    }),
    new CompressionPlugin(),
    new HTMLWebpackPlugin({
      template: './public/index.html',
    }),
  ],
  optimization: {
    minimizer: [
      new UglifyJsPlugin({
        parallel: true,
        sourceMap: true,
        cache: true,
      }),
    ],
    splitChunks: {
      cacheGroups: {
        default: false,
        commons: {
          test: /[\\/]node_modules[\\/]/,
          name: 'vendors',
          chunks: 'all',
        },
        styles: {
          test: /\.css$/,
          name: 'style',
          chunks: 'all',
        },
      },
    },
  },
};