webpack.prod.js

const webpack = require('webpack');
const merge = require('webpack-merge');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const UglifyJSPlugin = require('uglifyjs-webpack-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const cssnano = require('cssnano');

const common = require('./webpack.common.js')({
  isProduction: true
});

module.exports = merge(common, {
  mode: 'production',
  devtool: 'source-map',
  plugins: [
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify('production')
    }),
    new MiniCssExtractPlugin({
      filename: '[name].css',
    }),
    new OptimizeCSSAssetsPlugin({
      cssProcessor: cssnano,
      cssProcessorOptions: {
        discardComments: {
          removeAll: true,
        },
        // Run cssnano in safe mode to avoid
        // potentially unsafe transformations.
        safe: true,
      },
    }),
  ],
  optimization: {
    minimizer: [
      new UglifyJSPlugin({
        sourceMap: true
      }),
    ],
    splitChunks: {
      cacheGroups: {
        commons: {
          test: /[\\/]node_modules[\\/]/,
          name: 'vendor',
          chunks: 'all'
        }
      }
    }
  },
});