Introduction to Node.js

If you’ve been working with JavaScript on the frontend, you’ve probably wondered:
"Can I use JavaScript outside the browser?"
The answer is yes — thanks to Node.js.

🚀 What is Node.js?

Node.js is an open-source, cross-platform runtime environment that lets you run JavaScript code outside the browser.
It’s built on Google’s V8 engine (the same engine powering Chrome), making it fast and efficient.

Key points:

• Runs JavaScript on the server-side
• Event-driven and non-blocking I/O (handles thousands of requests efficiently)
• Huge ecosystem of packages via npm

🔑 Why Use Node.js?

1. Single Language Everywhere
   Use JavaScript for both frontend and backend — less context switching.

2. Performance
   Non-blocking architecture makes it great for APIs, chat apps, and real-time features.

3. npm Ecosystem
   Access to millions of libraries — from authentication to file handling.

🛠 Simple Example

Here’s a minimal HTTP server using Node.js:

// Import Node's built-in http module
const http = require("http");
 
const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader("Content-Type", "text/plain");
  res.end("Hello, Node.js!");
});
 
server.listen(3000, () => {
  console.log("Server running at http://localhost:3000/");
});

Run this with:

node server.js

Visit http://localhost:3000 and you’ll see: Hello, Node.js!

📦 Installing Node.js

Download from nodejs.org

Check versions with:

node - v;
npm - v;

I recommend using nvm to manage Node versions.

⚡ Common Use Cases

• REST APIs & GraphQL servers

• Real-time apps (chats, notifications)

• CLI tools

• Static file servers

• Backend for SPAs and mobile apps

🎯 Final Thoughts

Node.js isn’t just “JavaScript on the server.” It’s a powerful platform that changed how developers build scalable, real-time applications.

If you’re already comfortable with JavaScript, learning Node.js is a natural next step to becoming a full-stack developer. 🚀