單獨放入文件夾的話，如果你使用了app.use你還是需要在你的api文件夾里面聲明app

推薦使用對應的route

// invoked for any requests passed to this router

router.use(function(req, res, next) {

  // .. some logic here .. like any other middleware

  next();

});

// will handle any request that ends in /events

// depends on where the router is "use()'d"

router.get('/events', function(req, res, next) {

  // ..

});