Developing Custom Express Middleware

In Express.js, middleware functions are like a chain of helpers that process incoming requests before they reach your final route handler.

• They have access to the request (req) and response (res) objects.
• They can modify these objects, end the request-response cycle, or pass control to the next middleware.
• Custom middleware allows you to add specific functionality tailored to your application's needs, such as logging, authentication, or data parsing.

Every Express middleware function follows a specific signature: (req, res, next).

• req (request): The incoming HTTP request object.
• res (response): The HTTP response object that Express sends back.
• next: A function that, when called, passes control to the next middleware function in the stack. If you don't call next(), the request-response cycle stops, and no further middleware or route handlers will execute.