webpack.config.js

// entry point -> output bundle
// .js$, .css$ -> $ denotes file must end with js/ css

const path = require('path')
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
const CompressionPlugin = require('compression-webpack-plugin')
const webpack = require('webpack')
const zopfli = require('@gfx/zopfli');

module.exports = {
  mode: 'production',
  entry: './src/app.js',
  output: {
    path: path.join(__dirname, 'public'),
    filename: 'bundle.js',
    publicPath: '/'
  },
  plugins: [
    new BundleAnalyzerPlugin(),
    new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
    // new CompressionPlugin({
    //   compressionOptions: {
    //      numiterations: 15
    //   },
    //   algorithm(input, compressionOptions, callback) {
    //     return zopfli.gzip(input, compressionOptions, callback);
    //   }
    // })
  ],
  module: {
    rules: [{
      loader: 'babel-loader',
      test: /\.js$/,
      exclude: /node_modules/
    }, {
      test: /\.s?css$/,
      use: [
        'style-loader',
        'css-loader',
        'sass-loader'
      ]
    },
    {
      test: /\.(png|jpg)$/,
      loader: 'url?limit=25000'
    }]
  },
  devtool: 'cheap-module-eval-source-map',
  devServer: {
    contentBase: path.join(__dirname, 'public'),
    historyApiFallback: true
  }
}