Express.js req.param() Function

Last Updated : 08 Jul, 2020

The req.param() function basically returns the value of param name when present. When parameters are passed, then it can be accessed using this function.

Syntax:

req.param(name [, defaultValue])

Parameter: The name parameter is the name of the paramter.

Return Value: String.

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;
    
app.get('/', function (req, res) {
    //reading single paramter
    console.log(req.param('title')); 
    res.end();
});
  
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 make a GET request to http://localhost:3000?title=GeeksforGeeks, then you will see the following output on your console:
```
Server listening on PORT 3000
GeeksforGeeks
```

Example 2: Filename: index.js

var express = require('express');
var app = express();
var PORT = 3000;
    
app.get('/', function (req, res) {
  
    // Reading multiple paramter
    console.log("Title:", req.param('title')); 
    console.log("Domain:", req.param('domain')); 
      
    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 make a GET request to http://localhost:3000?title=GeeksforGeeks&domain=CS, then you will see the following output on your console:

Server listening on PORT 3000
Title: GeeksforGeeks
Domain: CS

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

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