webpack.prod.js

const path = require('path');
const common = require('./webpack.common');
const {merge} = require('webpack-merge');
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const CssMinimizerPlugin = require("css-minimizer-webpack-plugin");

module.exports = merge(common, {
  mode: "production",
  output: {
    filename: "[name]-[contenthash].bundle.js",
    path: path.resolve(__dirname, "dist"),
    clean: true
  },
  optimization: {
    minimizer: [
      // For webpack@5 you can use the `...` syntax to extend existing minimizers (i.e. `terser-webpack-plugin`), uncomment the next line
      `...`,
      new CssMinimizerPlugin(),
    ],
  },
  plugins: [new MiniCssExtractPlugin({
    filename: '[name]-[contenthash].css'
  })],
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [MiniCssExtractPlugin.loader, "css-loader", "postcss-loader"]
      }
    ]
  }
});