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How to Create Index JS File in Node JS?

Last updated:
23rd Jun, 2023
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How to Create Index JS File in Node JS?


JavaScript has been among the most predominant programming languages over the past few decades. Java was the only client-side programming language that was easily accessible and decipherable. 

However, over time, Node JS was introduced. Node JS can execute every kind of JavaScript code without changing the browser. 

Node JS now plays a vital role in building modern applications and consists of various frontend frameworks like React, Angular JS, and Vue. All these frameworks are responsible for building scalable applications for clients. You can check out the Full Stack Software Development Bootcamp of upGrad to upgrade your skills with these frameworks. 

In this blog, you’ll learn how to make index for project file with Node JS. 

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What is Index JS File in Node JS?

Node JS is a cross-platform Javascript backend. It primarily runs on the V8 engine and executes the JavaScript code outside the browser. 

On the other hand, the Index JS file in Node JS is an initial file that runs once Node JS is executed. Index JS file primarily helps start and route the applications with other functionalities. Index JS File, along with Mongoose, Axios, and Express, help Node JS to function. 

Index JS files are the first to be served when opening an application or on a browser. The Index JS project files help Node JS to run seamlessly and provide a feasible user experience. 

Why is Index JS File Important in Node JS?

As mentioned, the Index JS file is useful for structuring codes. It acts as an initial page when working with Node JS. 

However, Index JS files have much more important roles to play with Node JS. Let’s see what they are. 

Namespace: While the Index file is used as a namespace, it contains exports for everything in the folder. This is useful when there are group entities under the framework of a single identifier. This, in turn, helps to win over the imported components through various sub-directories according to preference. 

Sub-folder imports: If the Index JS file contains a folder, it will prevent any other subfolders from being imported. However, the folder or the subfolder can also import stuff if needed. It could be enforced automatically without any manual labour. 

Encapsulation: When an Index JS file is used primarily as an encapsulation, it contains a series of primary entities like component, class and function in the folder. It also might contain many secondary items, which would be useful to expose any single interface. 

Index JS file is one of the important concepts to master in computer science. Check out upGrad’s Master of Science in Computer Science from LJMU to enhance your knowledge of in-demand software development skills.. 

Creating Index JS File in Node JS – Step-by-Step Guide

Here’s a step-by-step guide to creating an Index JS file in Node JS:

Initializing a Node JS Project

The npm init is needed to create a package.json file before initialising a Node JS project. Creating a new empty directory in the development environment and running npm init would create a package.json file. 

$ npm init

This utility will walk you through creating a package.json file.

It only covers the most common items and tries to guess sensible defaults.

See `npm help init` for definitive documentation on these fields

and exactly what they do.

Use `npm install <pkg>` afterwards to install a package and

save it as a dependency in the package.json file.

Press ^C at any time to quit.

package name: (my-new-project)

version: (1.1.0)

description: A sample chatbot project

entry point: (app.js)

test command:

git repository:

keywords: chatbot, AI, node.js

author: John Smith

license: (MIT)

About to write to /Users/<your-username>/my-new-project/package.json:


  "name": "my-new-project",

  "version": "1.1.0",

  "description": "A sample chatbot project",

  "main": "node.js",

  "scripts": {

    "test": "echo \"Error: no test specified\" && exit 1"


  "author": "John Smith",

  "license": "MIT"


Creating the Index.js File

The Index JS file is the first page served in any domain. While visiting an HTML page or a PHP page, it would take you to the Index JS file. However, it is slightly different while creating an Index JS in Node JS. 

  • Go to the Node JS website and download and install the node package file. 
  • Create the new project folder in the working directory. 
  • Navigate through the project’s location via the terminal and then run the npm-init-y. 
  • Open the project on a code editor and sublime or vs code. 
  • Create the Index JS file inside the project folder. 
  • Paste the codes below in the Index. JS file. 
  • Put the server on the terminal using Node Index. JS. 
  • Visit the browser localhost:8080
const serverPort = 8080;

const http = require("http");

// Create a server object

const server = http.createServer(function (req, res) {

  res.write("<h1>Hello World!</h1>"); 

  // Write a response to the client


  // End the response


// Start the server and listen on the specified port

server.listen(serverPort, function () {

  console.log(`Server running on localhost:${serverPort}`);


Adding Modules and Routes to the Index.js File

Adding up modules and routes to an Index JS file is simple. One has to follow certain steps and guides to add it up. They are: 

  • Set up Index JS 
  • Set up platforms.JS routes files 
  • Set up platform.JS model files 
  • Build a model file. 
  • Build out routes file. 
  • Configure POST request and then add it to a Platform. 
  • Configure a GET request for viewing all platforms. 
  • Configure a PUT request endpoint for modifying platforms. 
  • Configure a DELETE request endpoint to delete platforms. 
const customConfig = require('config');

const Joi = require('joi');

const customMongoose = require('mongoose');

const customPlatforms = require('./routes/platforms');

const customUsers = require('./routes/users');

const customAuth = require('./routes/auth');

const customExpress = require('express');

const app = customExpress();

if (!customConfig.get('PrivateKey')) {

  console.error('FATAL ERROR: PrivateKey is not defined.');




  .then(() => console.log('Now connected to MongoDB!'))

  .catch(err => console.error('Something went wrong', err));


app.use('/api/platforms', customPlatforms);

app.use('/api/users', customUsers);

app.use('/api/auth', customAuth);

const customPort = process.env.PORT || 4000;

app.listen(customPort, () => console.log(`Listening on port ${customPort}...`));

Testing the Index.js File

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Testing the Index.JS file in Node JS is similar to creating Index JS. One can test the Index JS file by running the server on the terminal using Node Index JS. 

  "customName": "custom-nodejs", 

  "customVersion": "2.0.0", 

  "customDescription": "Custom Node.js project", 

  "customMain": "custom-index.js", 

  "customScripts": { 

    "customTest": "echo \"Error: no test specified\" && exit 1" 


  "customKeywords": ["custom", "Node.js"], 

  "customAuthor": "John Doe", 

  "customLicense": "MIT" 


Best Practices for Index JS File in Node JS

Using Index JS files on Node JS is comparatively easier than using JavaScript. The following best practices will help you make the most of using Index JS in Node JS:  

  • Index JS file is appropriate for building a simple website. A CSD imported from a CDN or Content Delivery Network can be included in building this website.
  • Index JS file can be appropriate to get web resources for Axios. Axios would help retrieve data from several users from a JSON placeholder website. Since Node JS has a basic HTTPS module, this would facilitate the user to make all the API calls online effortlessly. 
  • Node JS alongside IndexJS can facilitate building a countdown time. This countdown timer would enable time management. 

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Index JS file in Node JS creates an alternative for JavaScripts that has established its dominance for commercial purposes. Node Index JS is straightforward to learn and indispensable if you’re looking to build backend applications quickly. 

If you want to learn more about Node Index JS, Index JS for project file, find index in JavaScript, and full-stack development, check out upGrad’s Executive PG Programme in Full Stack Development from IIITB. To enrol in this course, all you need is a bachelor’s degree with 50% prior coding knowledge. The postgraduate programme can be an excellent opportunity to upskill yourself with software development and enhance your coding game. 


Pavan Vadapalli

Blog Author
Director of Engineering @ upGrad. Motivated to leverage technology to solve problems. Seasoned leader for startups and fast moving orgs. Working on solving problems of scale and long term technology strategy.

Frequently Asked Questions (FAQs)

1What should be included in an Index JS file?

Since Index JS primarily handles application startups and routing, it also requires other modules to modify its functionality. While running a website, it comes in handy as a basic HTTP web server replacing traditional servers like Apache.

2What is the disadvantage of Index JS files?

Even though Index JS file is known to make the work of software developers easier, it has a significant disadvantage. Index JS file is known to take up a lot of storage. This is because it requires special software to run, which lacks efficiency in terms of storage.

3What are two major types of Index JS files?

The two major types of Index JS files are Primary Indexing and Sparse Indexing. It helps in sorting out the key storage efficiently.