Express is an routing and middleware framework. And we use express to managing the routes and middlewares. Also it provides some folder structures.
Middleware is something which you wanted to execute before executing any particular function. For example we need a login check before accessing the user dashboard and logout. That check is called middleware here.
In Express framework middleware has access to req (Request), res (Response) and next (Next route).
We validate the data through the request and if validation is true then return to the next action else we return to any URL like login using res (Response). ...