webpack.prod.js

const { merge } = require('webpack-merge');
const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer');
const CompressionPlugin = require('compression-webpack-plugin');
const CssMinimizerPlugin = require('css-minimizer-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const TerserPlugin = require('terser-webpack-plugin');
const common = require('./webpack.common');

module.exports = merge(common, {
  mode: 'production',
  devtool: 'source-map',
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: [
          {
            loader: 'babel-loader',
            options: {
              presets: ['@babel/preset-env'],
            },
          },
        ],
      },
      {
        test: /\.css$/,
        use: [MiniCssExtractPlugin.loader, 'css-loader'],
      },
    ],
  },
  optimization: {
    minimize: true,
    minimizer: [
      new CssMinimizerPlugin(),
      new TerserPlugin(),
    ],
    splitChunks: {
      chunks: 'async',
      minSize: 20000,
      minRemainingSize: 0,
      minChunks: 1,
      maxAsyncRequests: 30,
      maxInitialRequests: 30,
      enforceSizeThreshold: 50000,
      cacheGroups: {
        defaultVendors: {
          test: /[\\/]node_modules[\\/]/,
          priority: -10,
          reuseExistingChunk: true,
        },
        default: {
          minChunks: 2,
          priority: -20,
          reuseExistingChunk: true,
        },
      },
    },
  },
  plugins: [
    new BundleAnalyzerPlugin(),
    new CompressionPlugin(),
    new MiniCssExtractPlugin(),
  ],
});