webpack.config.js

const path = require('path');
const webpack = require('webpack');
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;

const SRC_DIRECTORY = path.resolve(__dirname, 'src');
const DIST_DIRECTORY = path.resolve(__dirname, 'dist');

module.exports = {
  entry: SRC_DIRECTORY,
  externals: [
    {
      react: {
        root: 'React',
        commonjs2: 'react',
        commonjs: 'react',
        amd: 'react'
      }
    }
  ],
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: { cacheDirectory: true }
        }
      },
      {
        test: /\.(gif|jpe?g|png|svg)$/,
        use: {
          loader: 'url-loader',
          options: { name: '[name].[ext]' }
        }
      }
    ]
  },
  output: {
    filename: 'ReactNative.js',
    library: 'ReactNative',
    libraryTarget: 'umd',
    path: DIST_DIRECTORY
  },
  plugins: [
    new BundleAnalyzerPlugin({
      analyzerMode: 'static',
      openAnalyzer: false
    }),
    new webpack.DefinePlugin({ 'process.env.NODE_ENV': JSON.stringify('production') }),
    new webpack.optimize.UglifyJsPlugin({
      compress: {
        dead_code: true,
        drop_console: true,
        screw_ie8: true,
        warnings: false
      }
    })
  ]
};