Backend with Node.js
🛡️ Middleware in Express
Intermediate functions (middleware): how they chain together, when they call next() and when they stop the request.
What you'll learn
- Implement middleware with the
(req, res, next)signature and decide between callingnext()or responding - Chain global middleware (
app.use) and per-route middleware in the correct order - Stop the request with the appropriate response (
401without authorization,400for invalid data) - Enrich the
reqobject with data for the following middleware and handlers
Lessons
Middleware and nextFunctions that run before the handler. The middleware chainHow they chain and run in order.Practice this module in the app
DevPath is a hands-on course: you read the theory here; in the app you put it into practice with exercises that really run, offline.
Start free in the app →