Express.js res.links() Function

The res.links() function is used to join the links provided as properties of the parameter to populate the response’s Link HTTP header field.
Syntax:

res.links( links )

Parameter: The link parameter describes the name of the link to be joined.
Return Value: It returns an Object.
Installation of express module:

1. You can visit the link to Install express module. You can install this package by using this command. 
   

npm install express

1. After installing the express module, you can check your express version in command prompt using the command. 
   

npm version express

1. 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

javascript

var express = require('express');
var app = express();
var PORT = 3000;

// Without middleware
app.get('/', function(req, res){
    res.links({
        next: 'http://demo.com?page=2',
        middle: 'http://demo.com?page=4',
        last: 'http://demo.com?page=6'
    });

    console.log(res.get('link'));
});

app.listen(PORT, function(err){
    if (err) console.log(err);
    console.log("Server listening on PORT", PORT);
});

Steps to run the program:

1. The project structure will look like this: 
   

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

npm install express

1. Run index.js file using below command: 
   

node index.js

1. Output:
   

Server listening on PORT 3000

2. Now open browser and go to http://localhost:3000/, now check your console and you will see the following output: 
   

Example 2: Filename: index.js

javascript

var express = require('express');
var app = express();
var PORT = 3000;

// With middleware
app.use('/', function(req, res, next){
    res.links({
        next: 'http://demo.com?page=2',
        middle: 'http://demo.com?page=4',
        last: 'http://demo.com?page=6'
    });
    next();
})

app.get('/', function(req, res){
    console.log(res.get('link'));
    res.send();
});

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 open browser and go to http://localhost:3000/, now check your console and you will see the following output: 

Reference: https://expressjs.com/en/5x/api.html#res.links