Express.js express.Router() Function
The express.Router() function is used to create a new router object. This function is used when you want to create a new router object in your program to handle requests.
Syntax:
express.Router( [options] )
Optional Parameters:
- case-sensitive: This enables case sensitivity.
- mergeParams: It preserves the req.params values from the parent router.
- strict: This enables strict routing.
Return Value: This function returns the New Router Object.
Installation of express module:
- You can visit the link to Install express module. You can install this package by using this command.
npm install express
- After installing the express module, you can check your express version in command prompt using the command.
npm version express
- After that, you can just create a folder and add a file for example, index.js. To run this file you need to run the following command.
node index.js
Example 1: Filename: index.js
var express = require( 'express' ); var app = express(); var PORT = 3000; // Single routing var router = express.Router(); router.get( '/' , function (req, res, next) { console.log( "Router Working" ); res.end(); }) app.use(router); app.listen(PORT, function (err){ if (err) console.log(err); console.log( "Server listening on PORT" , PORT); }); |
Steps to run the program:
- The project structure will look like this:
- Make sure you have installed express module using the following command:
npm install express
- Run index.js file using below command:
node index.js
Output:
Server listening on PORT 3000
- Now open your browser and go to http://localhost:3000/, you will see the following output on your screen:
Server listening on PORT 3000 Router Working
Example 2: Filename: index.js
var express = require( 'express' ); var app = express(); var PORT = 3000; // Multiple routing var router1 = express.Router(); var router2 = express.Router(); var router3 = express.Router(); router1.get( '/user' , function (req, res, next) { console.log( "User Router Working" ); res.end(); }); router2.get( '/admin' , function (req, res, next) { console.log( "Admin Router Working" ); res.end(); }); router2.get( '/student' , function (req, res, next) { console.log( "Student Router Working" ); res.end(); }); app.use(router1); app.use(router2); app.use(router3); app.listen(PORT, function (err){ if (err) console.log(err); console.log( "Server listening on PORT" , PORT); }); |
Run index.js file using below command:
node index.js
Now make a GET request to http://localhost:3000/user, http://localhost:3000/admin and http://localhost:3000/student, then you will see the following output on your console:
Server listening on PORT 3000 User Router Working Admin Router Working Student Router Working
Reference: Offical Documentation