Express.js Middleware Tutorial
  Developers who are new to Express often get confused with the difference between route handler and middleware. Therefore they also get confused with the difference between  app.use() ,  app.all() ,  app.get() ,  app.post() ,  app.delete()  and  app.put()  methods.   In this tutorial I will explain the exact difference between a middleware and route handler. And also how to use the  app.use() ,  app.all() ,  app.get() ,  app.post() ,  app.delete()  and  app.put()  methods correctly.   Route Handler   app.all() ,  app.get() ,  app.post() ,  app.delete()  and  app.put()  methods are all used to define routes. A route is used to handle a HTTP request. A route is a combination of a path and callback, which is executed when a request’s path is matches. The callback is called as the route handler.   The difference between  app.all() ,  app.get() ,  app.post() ,  a...