Express.js router.METHOD() Function

The router.METHOD() method provides the routing functionality in Express, where METHOD is one of the HTTP methods, such as GET, PUT, POST, and so on, in lowercase. 

Syntax:

router.METHOD(path, [callback, ...] callback)

Parameter: The path parameter specifies the path on the URL and callback is the function that is executed when this path is called.

Return Value: Since, it provides the routing functionality, so it can return responses. 

Installation of the express module:

You can visit the link to Install the 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 the 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

Project Structure:

Example 1: Filename: index.js

javascript

const express = require('express');
const app = express();
const router = express.Router();
const PORT = 3000;

// Single route
router.get('/user', function (req, res, next) {
    console.log("GET request called");
    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:

Make sure you have installed the express module using the following command:

npm install express

Run the index.js file using the below command:

node index.js

Output:

Console Output:

Server listening on PORT 3000

Now make a GET request to http://localhost:3000/, you can see the following output on your screen:

Server listening on PORT 3000
GET request called

Example 2: Filename: index.js

javascript

const express = require('express');
const app = express();
const router = express.Router();
const PORT = 3000;

// Multiple routes
router.get('/user', function (req, res, next) {
    console.log("GET request called");
    res.end();
});

router.post('/user', function (req, res, next) {
    console.log("POST request called");
    res.end();
});

router.delete('/user', function (req, res, next) {
    console.log("DELETE request called");
    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:

Run the index.js file using the below command:

node index.js

Output:

Now make GET, POST, and DELETE request to http://localhost:3000/, you can see the following output on your screen:

Server listening on PORT 3000
GET request called
POST request called
DELETE request called

Reference: https://expressjs.com/en/4x/api.html#router.METHOD