webpack.config.babel.js

const { resolve } = require('path');
const UglifyJSPlugin = require('uglifyjs-webpack-plugin');
const dist = resolve('dist');

module.exports = {
  entry: './client/js/index.js',
  module: {
    rules: [
      {
        test: /\.jsx?/i,
        exclude: /node_modules/,
        loader: 'babel-loader',
      }
    ],
    loaders: [
      {
        test: /\.jsx?/i,
        exclude: /node_modules/,
        loader: 'babel-loader',
        query: {
          presets: [
            ['env', {
              'targets': {
                'browsers': [
                  'last 2 Chrome versions',
                  'last 2 Firefox versions',
                  'last 2 Safari versions',
                  'last 2 Edge versions',
                  'last 2 iOS versions',
                  'last 2 ChromeAndroid versions'
                ]
              }
            }],
            'stage-0'
          ]
        }
      }
    ]
  },
  plugins: [
    new UglifyJSPlugin({
      uglifyOptions: {
        keep_fargs: false,
        passes: 3
      }
    })
  ],
  output: {
    filename: 'bundle.js',
    path: dist
  },
  resolve: {
    alias: {
      "react-dom/server": "preact-render-to-string",
      "react-dom/test-utils": "preact-test-utils",
      "react-dom": "preact-compat-enzyme",
      "react-test-renderer/shallow": "preact-test-utils",
      "react-test-renderer": "preact-test-utils",
      "react-addons-test-utils": "preact-test-utils",
      "react-addons-transition-group": "preact-transition-group",
      "react": "preact-compat-enzyme"
    }
  }
}