Express.js req.param() Function

The req.param() function basically returns the value of the 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 parameter.

Return Value: String.

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 

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

app.get('/', function (req, res) {
    //reading single parameter
    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: 

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:

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 

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

app.get('/', function (req, res) {

    // Reading multiple parameter
    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);
});

Steps to run the program:

Run the index.js file using the 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: 

Output:

Console Output:

Server listening on PORT 3000

Browser Output:

Title: GeeksforGeeks
Domain: CS

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