webpack.config.prod.js

const {merge} = require('webpack-merge');
const webpackCommon = require('./webpack.config.common');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const OptimizeCssAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const TerserPlugin = require('terser-webpack-plugin');

module.exports = merge(webpackCommon, {
  mode: 'production',
  devtool: 'source-map',
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [MiniCssExtractPlugin.loader, 'css-loader']
      },
    ]
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: '[name].[contenthash].css'
    })
  ],
  optimization: {
    minimizer: [
      new OptimizeCssAssetsPlugin({
        cssProcessorOptions: {
          map: {
            inline: false,
            annotation: true
          }
        }
      }),
      new TerserPlugin({
        parallel: true,
        cache: true,
        sourceMap: true
      })
    ],
  }
});