webpack.config.js

const path = require('path');
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
const webpack = require('webpack');
const TerserPlugin = require('terser-webpack-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const DuplicatePackageCheckerPlugin = require('duplicate-package-checker-webpack-plugin');
const webpack = require('webpack');
const TerserPlugin = require('terser-webpack-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');

module.exports = {
  entry: ['@babel/polyfill', './src/index.js'],
  output: {
    filename: 'main.js',
    path: path.resolve(__dirname, 'dist'),
    chunkFilename: '[name].chunk.js',
  },
  mode: process.env.NODE_ENV,
  module: {
    loaders: [{
      test: /\.jsx$/,
      loader: 'babel-loader',
      query: {
        presets: ['env', 'react'],
      },
    }],
  },
  plugins: [
    new webpack.DefinePlugin({
      'process.env': {
        NODE_ENV: JSON.stringify('production'),
      },
    }),
    new webpack.optimize.DedupePlugin(),
    new UglifyJsPlugin(),
    new webpack.optimize.AggressiveMergingPlugin(),
    new webpack.ContextReplacementPlugin(
      /highlight\.js\/lib\/languages$/,
      new RegExp('^./(javascript)$'),
    ),
    new DuplicatePackageCheckerPlugin(),
    new webpack.optimize.AggressiveMergingPlugin(),
    new webpack.ContextReplacementPlugin(
      /highlight\.js\/lib\/languages$/,
      new RegExp('^./(javascript)$'),
    ),
  ],
  optimization: {
    minimize: true,
    minimizer: [
      new TerserPlugin({
        terserOptions: {
          parse: {
            ecma: 8,
          },
          compress: {
            ecma: 5,
            warnings: false,
            inline: 2,
          },
          mangle: {
            safari10: true,
          },
          output: {
            ecma: 5,
            comments: false,
            ascii_only: true,
          },
        },
        parallel: true,
        cache: true,
      }),
      new OptimizeCSSAssetsPlugin({
        cssProcessorOptions: {
          map: {
            inline: false,
            annotation: true,
          },
        },
      }),
    ],
  },
};