Express + Webpack Dev Server

server.coffee

if process.env.NODE_ENV is 'development'
  app.all /(^\/(js|css)\/(.+))|(hot-update\.(.+)$)/, (req, res, next) ->
    url = 'http://localhost:3001' + req.originalUrl
    callback = (error, response, body) =>
      if body?
        res.writeHead response.statusCode, response.headers
        res.end(body)
      else
        next()
    request(url, callback)