Webpack + React + Stylus, Dev: Hotloat, Build: File Output

gistfile1.txt

var webpack = require('webpack'),
	path = require('path'),
	ExtractTextPlugin = require("extract-text-webpack-plugin"),
	isDev = process.env.NODE_ENV;

var config = {
	cache: true,
	resolve: {
		extensions: ["", ".js", ".css", ".styl"]
	},
	entry: [
		'webpack-dev-server/client?http://localhost:3001',
		'webpack/hot/dev-server',
		'./src/app.js'
	],
	output: {
		path: path.join(__dirname, '/build/'),
		filename: 'app.js',
		publicPath: 'http://localhost:3001/assets/'
	},
	module: {
		loaders: [
			{test: /\.js$/, exclude: /node_modules/, loaders: ['react-hot', 'jsx?harmony']},
			{test: /\.css$/, loader: isDev
				? "style-loader!css-loader"
				: ExtractTextPlugin.extract("css", "css-loader")},
			{test: /\.styl$/, loader: isDev
				? "style-loader!css-loader!stylus-loader"
				: ExtractTextPlugin.extract("stylus", "css-loader!stylus-loader")}
		]
	},
	plugins: [
		new webpack.HotModuleReplacementPlugin(),
		isDev ? new ExtractTextPlugin("app.css", {allChunks: true}) : ""
	]
};

if (process.env.NODE_ENV === "dev") {
	config.devtool = 'eval'; // This is not as dirty as it looks. It just generates source maps without being crazy slow.
}

module.exports = config;

I found this to fix it.
webpack-contrib/stylus-loader#80