Order of router precedence in express.js

Question

I would like to understand the order precedence in express.js. For example, as bellow code

var routes = require('./routes/index'); var users = require('./routes/users'); var api = require('./routes/api');   app.use('/api', api); app.use('/users', users);  app.use('/:name', function(req, res, next) {         console.log('from app.js name:', req.params.name);         res.render('index', {         title: req.params.name     }); }, routes);  app.use('/', function(req, res, next) {        res.render('index', {         title: 'MainPage'     }); }); 

If a request come from client localhost:3000/api/abc and localhost:3000/user/abc, the response from api and user module. But if I make a request like localhost:3000/myName/xyz, the app module return a response. This behavior let me concern about what is precedence of expressjs and what is correct order for router modules. Why routers do not confuse between actions "api", "users" and parameter ":name". Please let me understand clearly how express does and what is precedence.

Answer 1

The order is first come first serve.

In your case, if user hits /api, he will get response from api, but if you write /:name route before /api, /:name will serve for /api requests also.

Case1: /api will serve requests for /api.

var routes = require('./routes/index'); var users = require('./routes/users'); var api = require('./routes/api');   app.use('/api', api); app.use('/users', users);  app.use('/:name', function(req, res, next) {         console.log('from app.js name:', req.params.name);         res.render('index', {         title: req.params.name     }); }, routes);  app.use('/', function(req, res, next) {        res.render('index', {         title: 'MainPage'     }); }); 

Case2: /:name serves requests for /api and /users

var routes = require('./routes/index'); var users = require('./routes/users'); var api = require('./routes/api');  app.use('/:name', function(req, res, next) {         console.log('from app.js name:', req.params.name);         res.render('index', {         title: req.params.name     }); }, routes);  app.use('/api', api); app.use('/users', users);    app.use('/', function(req, res, next) {        res.render('index', {         title: 'MainPage'     }); });