The router-level Middleware is used to bind to a specific instance of express.Router().Built-in Middleware : The built-in Middleware was introduced with version 4.x. It ends the dependency on Connect.
There are the following built-in middleware functions in Express.js :
* static : It is used to serve static assets such as HTML files, images, etc.
* json : It is used to parse the incoming requests with JSON payloads. It is available with Express 4.16.0+
* urlencoded : It is used to parse the incoming requests with URL-encoded payloads. It is available with Express 4.16.0+
