Express.js req.body Property

The req.body property contains key-value pairs of data submitted in the request body. By default, it is undefined and is populated when you use a middleware called body-parsing such as express.urlencoded() or express.json().

Syntax:

req.body

Parameter: No parameters.

Return Value: 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

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

   npm version express

3. 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;

// For parsing application/json
app.use(express.json());

// For parsing application/x-www-form-urlencoded
app.use(express.urlencoded({ extended: true }));

app.post('/profile', function (req, res) {
  console.log(req.body);
  res.send();
});

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

   npm install express

3. Run index.js file using below command:

   node index.js

   Output:

   Server listening on PORT 3000
   

4. Now make POST request to http://localhost:3000/profile with following body:

    {
        "title":"Greetings from GeeksforGeeks"
    }
   

   Now you can see the following output on your console:

   Server listening on PORT 3000
   { title: 'Greetings from GeeksforGeeks' }
   

Example 2: Filename: index.js

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

app.use(express.json());
app.use(express.urlencoded({ extended: true }));

app.post('/signup', function (req, res) {
  var data = req.body;

  console.log("Name: ", data.name);
  console.log("Age: ", data.age);
  console.log("Gender: ", data.gender);

  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 make a POST request to http://localhost:3000/signup with the following request body:

 {
     "name": "Gourav",
     "age": 13,
     "gender":"Male"
 }

Output: Now you will see the following output on your console screen:

Server listening on PORT 3000
Name:  Gourav
Age:  13
Gender:  Male

Reference: https://expressjs.com/en/4x/api.html#req.body