Express.js res.cookie() Function

The res.cookie() function is used to set the cookie name to value. The value parameter may be a string or object converted to JSON.

Syntax:

res.cookie(name, value [, options])

Parameters: The name parameter holds the name of the cookie and the value parameter is the value assigned to the cookie name. The options parameter contains various properties like encode, expires, domain, etc. 

Return Value: It returns an Object. 

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 PORT = 3000;

// Without middleware
app.get('/', function (req, res) {

    // key-value
    res.cookie('name', 'geeksforgeeks');
    res.send("Cookie Set");
});

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

Browser Output:

Open your browser and go to http://localhost:3000/, now you the following output on your screen:

Cookie Set

Example 2: Filename: index.js

javascript

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

// With middleware
app.use('/', function (req, res, next) {
    res.cookie('title', 'GeeksforGeeks');
    res.send("Cookie Set");
    next();
})

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

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:

Console Output:

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

Server listening on PORT 3000
Cookie SET

Browser Output:

And you will see the following output on your browser:

Cookie Set

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