Express: Route parameters

Route parameters are parameters whose values are set dynamically on a page url.

For example, the url can be like

/users/:userId/movieTickets/:bookingId

When you call the above url like below.

/users/krishna123/movieTickets/booking789

Then userId is mapped to the value krishna123 and

bookingId is mapped to the value booking 789.

Captured alues from the routing object are mapped to 'req.params' object. Let’s see it by an example.

index.js

var express = require('express')

var app = express()

app.get('/users/:userId/movieTickets/:bookingId', function (req, res) {
  res.send(req.params);
});


var listener = app.listen(3000, () => {console.log('Application started on port ' + listener.address().port);});

Run index.js, and open the url ‘http://localhost:3000/users/krishna123/movieTickets/booking789’ in browser, you can see below kind of response.

You can access the route parameters using ‘.’ Notation.

index.js

var express = require('express')

var app = express()

app.get('/users/:userId/movieTickets/:bookingId', function (req, res) {
 var userId = req.params.userId
 var bookingId = req.params.bookingId
 
 var result = `User ${userId}'s booking id is ${bookingId}`
 res.send(result);
});


var listener = app.listen(3000, () => {console.log('Application started on port ' + listener.address().port);});

Run index.js and open the url ‘http://localhost:3000/users/krishna123/movieTickets/booking789’ in browser. You can see below message.

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