TOPIC OVERVIEW

Express.js/Middleware

Run reusable logic in the request pipeline before the final route handler responds.

18 QuestionsIntermediateHigh Priority ~12 min read

Middleware is one of the most important ideas in Express. A middleware function can inspect or modify a request, perform some work, and then call next() to pass control to the next middleware or route handler.

This makes middleware useful for tasks such as logging, authentication, validation, parsing request data, handling errors, and adding information to the request. Understanding the order in which middleware runs is especially important because it directly affects how an Express application behaves.

What you'll walk away knowing

How Express middleware works

How next() moves a request through the middleware chain

How application-level and router-level middleware differ

How middleware is used for authentication, logging, and validation

1What are middlewares?ExpertHigh 2How do we apply middleware to routes?ExpertHigh 3List some common middleware tasks?ExpertHigh 4write an example of route in express where edit request and response object using middleware functionExpertHigh

All Topics