webpack-prod.config.js

const CompressionPlugin = require('compression-webpack-plugin');
const TerserPlugin = require('terser-webpack-plugin');

module.exports = {
  mode: 'production',
  context: __dirname,
  entry: './source/_js/scripts.js',
  output: {
    path: __dirname + '/source/assets/',
    filename: 'bundle.js',
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env']
          },
        }      
      }
    ]
  },
  optimization: {
    minimize: true,
    minimizer: [new TerserPlugin({
    exclude: [/\.min\.js$/gi],
    })],
  },
  plugins: [
    new CompressionPlugin({
      // asset: '[path].gz[query]',
      algorithm: 'gzip',
      test: /\.js$|\.css$|\.html$/,
      threshold: 10240,
      minRatio: 0
    })
  ]
};