1. Asynchronous & Non-Blocking

• Unlike traditional server-side programming languages, Node.js does not wait for a task to finish before executing the next one.
• Example:

const fs = require(‘fs’);

fs.readFile(‘file.txt’, ‘utf8’, (err, data) => {

    if (err) throw err;

    console.log(data);

});

console.log(‘Reading file…’);

Output (Order may vary):

Reading file…

(file content)

  2. Single-Threaded but Highly Scalable

• Uses an event loop instead of creating multiple threads.
• Can handle thousands of requests without creating separate threads for each.

3. Event-Driven Architecture

• Uses the EventEmitter class to handle events asynchronously.
• Example:

const EventEmitter = require(‘events’);

const event = new EventEmitter();

event.on(‘greet’, () => {

    console.log(‘Hello, Event-Driven Programming!’);

});

event.emit(‘greet’);

Output: Hello, Event-Driven Programming!

  4. Built-in Modules

• Node.js provides various built-in modules:

Creating a Simple HTTP Server

Using Node.js, you can create a basic web server without needing Apache or Nginx.

Example:

const http = require('http');

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

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

    res.end('Hello, World!');

});

server.listen(3000, () => {

    console.log('Server running at http://localhost:3000/');

});

How to Run:

1. Save this as server.js
2. Run: node server.js
3. Open your browser and visit:
   http://localhost:3000
   You will see “Hello, World!” displayed.