Familiarize Yourself with Middleware Functions

Before moving to implementation, we need to understand middleware functions. Our API rate-limiting function is actually going to be a middleware function that can be reused in any of the API routes, with a configurable window and the maximum number of API calls allowed per IP address in that window.

What are middleware functions?

In Express.js, middlewares are functions that have access to the request (req) and response (res) objects in the application's request-response ...