webpack.prod.js

const TerserPlugin = require('terser-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const common = require('./webpack.common.js');
const { merge } = require('webpack-merge');

module.exports = function({ env: environmentType }) {
  return merge(common(environmentType), {
    mode: 'production',
    devtool: false,
    module: {
      rules: [
        {
          test: /\.(j|t)sx?$/,
          exclude: /node_modules/,
          use: {
            loader: 'babel-loader',
            options: {
              cacheDirectory: true,
            },
          },
        },
        {
          test: /\.scss$/i,
          exclude: [/node_modules/],
          use: [MiniCssExtractPlugin.loader, 'css-loader', 'sass-loader'],
        },
        {
          test: /\.css$/,
          use: [MiniCssExtractPlugin.loader, 'css-loader'],
        },
      ],
    },
    optimization: {
      splitChunks: {
        cacheGroups: {
          vendors: {
            test: /[\\/]node_modules[\\/]/,
            name: 'vendors',
            chunks: 'all',
          },
        },
      },
      minimize: true,
      minimizer: [
        new TerserPlugin({
          parallel: true,

          test: /\.js(\?.*)?$/i,
        }),
      ],
    },
  });
};