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 which is to be sent in the response.
Return Value: It retuns an 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; // 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:
- 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 browser and go to http://localhost:3000/, now on your screen you will see the following output:
{"user":"geek"}
Example 2: Filename: index.js
var express = require( 'express' ); var app = express(); var PORT = 3000; // With middlware 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); }); |
Run index.js file using below command:
node index.js
Now open a browser and go to http://localhost:3000/, now on your screen you will see the following output:
{"title":"GeeksforGeeks"}
And you will see the following output on your console:
User Page
Reference: https://expressjs.com/en/4x/api.html#res.json