Express res.json() Function (original) (raw)

Last Updated : 07 Jan, 2025

The **res.json() function sends a JSON response. This method sends a response (with the correct content-type) that is the parameter converted to a JSON string using the JSON.stringify() method.

**Syntax:

res.json( [body] )

**Parameters: The body parameter is the body that is to be sent in the response.

**Return Value: It returns an Object.

**Steps to Install the Express Module:

**Step 1: You can install this package by using this command.

npm install express

**Step 2: After installing the express module, you can check your express version in the command prompt using the command.

npm version express

**Project Structure:

Project Structure

The updated dependencies in package.json file will look like:

"dependencies": {
"express": "^4.18.2",
}

**Example 1: Below is the code of res.json() Function implementation.

javascript `

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

// Without middleware app.get('/', function (req, res) { res.json({ user: 'geek' }); });

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

**Console Output:

Server listening on PORT 3000

**Browser Output: Now open the browser and go to **http://localhost:3000/, now on your screen you will see the following output:

{"user":"geek"}

**Example 2: Below is the code of res.json() Function implementation.

javascript `

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

// With middleware app.use('/', function (req, res, next) { res.json({ title: "GeeksforGeeks" }) next(); })

app.get('/', function (req, res) { console.log("User Page") res.end(); });

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

**Browser Output: Now open a browser and go to **http://localhost:3000/, now on your screen you will see the following output:

{"title":"GeeksforGeeks"}

**Console Output: And you will see the following output on your console:

User Page