Express router.use() Method
What you’ll learn
- How to mount router-level middleware with and without path prefixes.
- How to mount child routers inside a parent router module.
- How router-level middleware order affects route handling.
- How to avoid scope/order mistakes when composing routers.
Syntax
javascript
router.use(middleware)
router.use(path, middleware)
router.use(path, childRouter)1
Router-level middleware for all routes
javascript
router.use(function (req, res, next) {
console.log('Router hit:', req.method, req.originalUrl);
next();
});2
Path-scoped middleware inside router
javascript
router.use('/admin', function (req, res, next) {
if (!req.user || !req.user.isAdmin) return res.status(403).send('Forbidden');
next();
});3
Mount child router from parent router
javascript
var usersRouter = require('./users-router');
router.use('/users', usersRouter);
// '/users' paths now handled by usersRouter⚠️ Common pitfalls
- Mounting middleware after routes that should have used it.
- Forgetting
next()in middleware and causing request hangs. - Assuming router-level path prefixes match differently than app-level prefixes.
❓ FAQ
It mounts middleware or another router inside the current router.
Yes. You can use router.use('/admin', middleware) to scope middleware to matching subpaths.
Both mount middleware, but router.use() is scoped to one router module while app.use() is app-level.
Yes. It is common to mount feature routers like router.use('/users', userRouter).
Yes, for matching paths it runs regardless of HTTP method unless filtered later.
Did you know?
router.use() mounts middleware or child routers on a router instance, letting you build modular middleware pipelines.
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