Understanding Node.js Middleware: Express.js’s Hidden Gem
Mastering Middleware in Node.js
Express.js is a powerful, unopinionated, minimalist web framework for Node.js, which offers an effective set of features to develop web and mobile applications. Among them, one strong feature is middleware.
In Express.js applications, middleware functions enable developers to change the request and response objects, end the requests, and call the next middleware function in the stack. This article takes a stab at demystifying middleware by showing how important the feature is in Express.js and guiding you through mastering its usage.
What is Middleware?
In its most general form, middleware is a function that takes the request object (`req`), the response object (`res`) and the next middleware function in the application’s request-response cycle. These functions can do any of the following (and more):
- Execute any code.
- Change the request and response objects.
- Stopping the request-response loop.
- The next middleware in the stack is called.
It could include such middleware functions to log, perform authentications, handle errors, and a lot more. Express.js applications consist of…
