🚀 Basic Node.js Tutorial

💡 A beginner-friendly repository to learn Node.js fundamentals, core concepts, and backend basics in a simple and structured way.

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✨ About Node.js

🟢 Node.js is a JavaScript runtime built on Chrome's V8 engine 🟢 It allows JavaScript to run outside the browser (server-side) 🟢 Used to build fast, scalable network applications

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📜 History

In 2009, Ryan Dahl created Node.js with the idea:

“Why not run JavaScript outside the browser?”

He used the V8 Engine (C++) to execute JavaScript on the server — and Node.js was born 🚀

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⚙️ V8 Engine

• JavaScript engine developed by Chrome

• Converts JavaScript into machine code

• Other engines:

  • Firefox → SpiderMonkey
  • Edge → Chakra

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🎯 Where Node.js is Used

• ⚡ I/O bound applications
• 📡 Real-time chat apps
• 📊 Data streaming apps
• 🌐 APIs & backend services

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🛠️ Installation

Step 1:

Download Node.js 👉 https://nodejs.org/en/download/

Step 2:

Install it

Step 3:

Verify installation

node -v
npm -v

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📦 NPM (Node Package Manager)

• 📚 Largest software registry in the world
• 📥 Install packages easily
• ⚙️ Manage dependencies

Example:

npm install express

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🧠 ES6 (Modern JavaScript)

• Introduced in 2015

• Adds features like:

  • Arrow functions ➡️
  • let / const
  • Promises
  • Modules

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💻 REPL (Read Eval Print Loop)

Node.js provides an interactive shell:

• R → Read input
• E → Evaluate
• P → Print output
• L → Loop

Features:

• Run JS expressions
• Use variables
• Multiline code
• _ → last result

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🧰 Useful REPL Commands

.help       # Show help
.editor     # Enter editor mode

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📦 Core Modules

Node.js provides built-in modules:

• fs → File system
• http → Web server
• path → File paths
• events → Event handling

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🌐 Creating a Web Server

Node.js can create its own web server:

const http = require('http');

http.createServer((req, res) => {
  res.write("Hello World");
  res.end();
}).listen(3000);

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📄 JSON

• Lightweight data format
• Used for data exchange
• Common in APIs

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🔌 API (Application Programming Interface)

• Allows communication between applications

• Used in:

  • Web apps
  • Mobile apps
  • Services

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⚡ Event Module

Node.js is event-driven

const EventEmitter = require('events');
const event = new EventEmitter();

event.on('sayHello', () => {
  console.log('Hello World!');
});

event.emit('sayHello');

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🌊 Streams in Node.js

Streams handle data efficiently:

1. Readable
2. Writable
3. Duplex
4. Transform

👉 Used in real-time processing (video, audio, etc.)

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⌨️ Terminal Commands

ctrl + `        # Open terminal
dir             # List files
cd ..           # Go back
mkdir folder    # Create folder
node app.js     # Run file
nodemon app.js  # Auto restart server

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🎯 Purpose of This Repo

This project was created to:

• Learn Node.js fundamentals
• Understand backend development basics
• Build a strong foundation for full-stack development

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🚀 Future Improvements

• Add Express.js examples
• Add REST API projects
• Add MongoDB integration
• Convert into full backend course

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⚡ Note

This repository reflects my early journey into backend development using Node.js.

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🙌 Author

Sastik Kumar Das

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⭐ Support

If you find this helpful, give it a ⭐ on GitHub!