webpack.config.js

'use strict'

const path = require('path')
const TerserPlugin = require('terser-webpack-plugin')
const nodeExternals = require('webpack-node-externals')

module.exports = {
  mode: 'production',
  entry: path.resolve(__dirname, 'src/index.js'),
  output: {
    path: path.resolve(__dirname, './dist'),
    filename: 'index.js',
    library: '',
    libraryTarget: 'commonjs'
  },
  externals: [nodeExternals()],
  optimization: {
    minimize: false,
    minimizer: [
      new TerserPlugin({
        terserOptions: {
          parse: {
            // we want terser to parse ecma 8 code. However, we don't want it
            // to apply any minfication steps that turns valid ecma 5 code
            // into invalid ecma 5 code. This is why the 'compress' and 'output'
            // sections only apply transformations that are ecma 5 safe
            // https://github.com/facebook/create-react-app/pull/4234
            ecma: 8,
          },
          compress: {
            ecma: 5,
            warnings: false,
            // Disabled because of an issue with Uglify breaking seemingly valid code:
            // https://github.com/facebook/create-react-app/issues/2376
            // Pending further investigation:
            // https://github.com/mishoo/UglifyJS2/issues/2011
            comparisons: false,
            // Disabled because of an issue with Terser breaking valid code:
            // https://github.com/facebook/create-react-app/issues/5250
            // Pending futher investigation:
            // https://github.com/terser-js/terser/issues/120
            inline: 2,
          },
          mangle: {
            safari10: true,
          },
          output: {
            ecma: 5,
            comments: false,
            // Turned on because emoji and regex is not minified properly using default
            // https://github.com/facebook/create-react-app/issues/2488
            ascii_only: true,
          },
        },
        // Use multi-process parallel running to improve the build speed
        // Default number of concurrent runs: os.cpus().length - 1
        // Setting parallel to true hangs the build
        // see https://github.com/webpack-contrib/terser-webpack-plugin/issues/21
        parallel: true,
        // Enable file caching
        cache: true,
        sourceMap: false,
      }),
    ],
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /(node_modules)/,
        loader: 'babel-loader',
        options: {
          cacheDirectory: true,
          // Save disk space when time isn't as important
          cacheCompression: true,
          compact: true,
        }
      }
    ]
  }
};