webpack.config.js

// This is needed for webpack to compile JavaScript.
// Many OSS React Native packages are not compiled to ES5 before being
// published. If you depend on uncompiled packages they may cause webpack build
// errors. To fix this webpack can be configured to compile to the necessary
// `node_module`.
const babelLoaderConfiguration = {
	test: /\.js$/,
	// Add every directory that needs to be compiled by Babel during the build
	include: [
	  path.resolve(__dirname, 'src'),
	],
	use: {
	  loader: 'babel-loader',
	  options: {
		cacheDirectory: true,
		// This aliases 'react-native' to 'react-native-web' and includes only
		// the modules needed by the app
		plugins: ['react-native-web/babel'],
		// The 'react-native' preset is recommended (or use your own .babelrc)
		presets: ['react-native']
	  }
	}
  };

module.exports = {
	module: {
		rules: [
		babelLoaderConfiguration,
		]
	},

	plugins: [
		// `process.env.NODE_ENV === 'production'` must be `true` for production
		// builds to eliminate development checks and reduce build size. You may
		// wish to include additional optimizations.
		new webpack.DefinePlugin({
			'process.env.NODE_ENV': JSON.stringify('production')
		})
	],

	resolve: {
		// If you're working on a multi-platform React Native app, web-specific
		// module implementations should be written in files using the extension
		// `.web.js`.
		extensions: [ '.web.js', '.js' ]
	}
}