Express.js | app.set() Function

The app.set() function is used to assign the setting name to value. You may store any value that you want, but certain names can be used to configure the behavior of the server. 

Syntax:

app.set(name, value)

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:

Filename: index.js 

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

app.set('title', 'GeeksforGeeks');

app.get('/', (req, res) => {
    res.send(app.get('title'));
})

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 open the browser and go to http://localhost:3000/, you will get the following output:

GeeksforGeeks

So this is how you can use the express app.set() function which assigns a setting name to a value.