Node First Application (original) (raw)

Last Updated : 25 Apr, 2026

NodeJS is widely used for building scalable and high-performance applications, particularly for server-side development. It is commonly employed for web servers, APIs, real-time applications, and microservices.

Creating Console-based Node Application

This section demonstrates how to execute JavaScript directly in Node.js using the console (REPL) without creating any files or project setup.

Running Node.js in the Console (No Setup Required)

Node.js lets you run JavaScript directly in the console using the REPL. Simply type node in the terminal to execute JavaScript interactively.

$ node

let name = "Jane";
console.log("Hello, " + name + "!");

**Output:

Screenshot-2026-03-02-110220

Node First Application

Creating Application with npm init and Installed Modules

Initialize a Node.js application using npm init and enhance its functionality by installing required modules.

**Step 1: Initialize a Node.js Project

mkdir my-node-app
cd my-node-app
npm init -y

**Step 2: Install Required Modules

We will install fs (for handling file operations) and path (for working with file paths).

npm install fs path

**Step 3: Create an index.js File

Create a simple HTTP server that reads and serves a file.

JavaScript `

import http from "http"; import fs from "fs"; import path from "path"; import { fileURLToPath } from "url";

const __filename = fileURLToPath(import.meta.url); const __dirname = path.dirname(__filename);

const server = http.createServer((req, res) => { const filePath = path.join(__dirname, "message.txt");

fs.readFile(filePath, "utf8", (err, data) => {
    if (err) {
        res.writeHead(500, { "Content-Type": "text/plain" });
        res.end("Error reading file");
    } else {
        res.writeHead(200, { "Content-Type": "text/plain" });
        res.end(data);
    }
});

});

server.listen(3000, () => { console.log("Server is running on port 3000"); });

`

**Step 4: Create a message.txt File

Create a message.txt file in the same directory and add some content:

JavaScript `

Hello, this is a Node.js application without Express!

`

**Step 5: Run the Application

node index.js

Creating Web-based Node Application

A web-based Node application consists of the following three important components:

**Step 1: Import required modules

Load Node modules using the required directive. Load the http module and store the returned HTTP instance into a variable.

**Syntax:

var http = require("http");

**Step 2: Creating a server in Node

Create a server to listen to the client's requests. Create a server instance using the createServer() method. Bind the server to port 8080 using the listen method associated with the server instance.

**Syntax:

http.createServer().listen(8080);

**Step 3: Read request and return response in Node

Read the client request made using the browser or console and return the response. A function with request and response parameters is used to read client requests and return responses.

**Syntax:

http.createServer(function (request, response) {...}).listen(8080);

**step 4: Create an index.js File

JavaScript `

var http = require('http');

http.createServer(function (req, res) {

res.writeHead(200, {'Content-Type': 'text/html'});

res.end('Hello World!');

}).listen(8080);

`

**Step 5: To run the program type the following command in terminal

node index.js

**Output:

first node application creatednode application hello world output

Core Components of a Node-First Application