webpack.config.js

const webpack = require('webpack')
const fs = require('fs')

// NODE_ENV
const nodeEnv = process.env.NODE_ENV || 'development'
const isProd = nodeEnv === 'production'

module.exports = (options) => {
	let entryFile, outputPath, isClient, isServer

	switch(options.side)
	{
		case 'client':
			entryFile = { client: './app/client.jsx' }
			outputPath = __dirname + '/app/public'
			isClient = true
			break

		case 'server':
			entryFile = { server: './app/server.js' }
			outputPath = __dirname + '/dist'
			isServer = true
			break
	}

	return {
		entry: entryFile,

		devtool: isProd ? 'source-map' : 'eval',

		output: {
			filename: '[name].bundle.js',
			path: outputPath
		},

		resolve: {
			extensions: ['.js', '.jsx', '.styl'],
			modules: ['node_modules', 'shared']
		},

		module: {
			rules: [
				{
					test: /\.jsx$/,
					exclude: /node_modules/,
					loader: "babel-loader",
					options: {
						presets: [
							["env", { "targets": { "browsers": ["last 2 versions"] } }],
							'react',
							'stage-2'
						]
					}
				},
				{
					test: /\.styl$/,
					use: [
						{
							loader: "style-loader"
						},
						{
							loader: "css-loader"
						},
						{
							loader: "postcss-loader",
							options: {
								plugins: () => {
									return [
										require('autoprefixer')({ browsers: 'last 2 versions' })
									]
								}
							}
						},
						{
							loader: "stylus-loader"
						}
					]
				}
			]
		},

		externals: isServer ? fs.readdirSync(__dirname + '/node_modules')
			.concat([
				'react-dom/server'
			])
			.reduce(function (ext, mod) {
				ext[mod] = 'commonjs ' + mod;
				return ext
			}, {}) : '',

		target: isServer ? 'node' : 'web',

		plugins: isProd ? [
			new webpack.DefinePlugin({ "process.env": { NODE_ENV: JSON.stringify('production') } }),
			new webpack.optimize.OccurrenceOrderPlugin(),
			new webpack.optimize.UglifyJsPlugin({
				compress: {
					warnings: false,
					screw_ie8: true,
					conditionals: true,
					unused: true,
					comparisons: true,
					sequences: true,
					dead_code: true,
					evaluate: true,
					if_return: true,
					join_vars: true,
				},
				output: {
					comments: false
				},
			}),
			new webpack.LoaderOptionsPlugin({ minimize: true, debug: false })
		] : []
	}
}