const { merge } = require('webpack-merge');
const base = require('./webpack.base.conf');
const OptimizeCss = require('optimize-css-assets-webpack-plugin');
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
const BundleAnalyzerPlugin =
  require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
const webpack = require('webpack');

module.exports = merge(base, {
  mode: 'production',
  optimization: {
    minimizer: [
      //压缩CSS代码
      new OptimizeCss(),
      //压缩js代码
      new UglifyJsPlugin({
        //启用文件缓存
        cache: true,
        //使用多线程并行运行提高构建速度
        parallel: true,
        sourceMap: false,
        output: {
          comments: false,
        },
      }),
    ],
    splitChunks: {
      cacheGroups: {
        vendor: {
          test: /[\\/]node_modules[\\/](react|react-dom)[\\/]/,
          name: 'vendor',
          chunks: 'all',
        },
      },
    },
  },
  plugins: [new BundleAnalyzerPlugin()],
});