Description: The middleware chain refers to the sequence of middleware functions that are executed for a request before reaching the final route handler in web applications using frameworks like Express.js. Each middleware function has access to the request object (req), the response object (res), and the next() function that allows passing control to the next function in the chain. This modular structure enables developers to add functionalities flexibly and scalably, such as authentication, error handling, data validation, and request logging. The middleware chain executes in the order they are defined, allowing precise control over the application’s flow. Additionally, each middleware can modify the request and response, facilitating the customization of the application’s behavior. This feature is fundamental in modern web application development, as it allows for a clear separation of concerns and better organization of code, resulting in more maintainable and understandable applications.
