Introduction to Node.js
Node.js is a runtime environment that allows you to run JavaScript code outside of a web browser. It's built on Chrome's V8 JavaScript engine and enables developers to create server-side applications using JavaScript.
Key Points:
- Open-source and cross-platform
- Event-driven, non-blocking I/O model
- Large ecosystem with npm (Node Package Manager)
- Active community and corporate backing
Origins and History
2009
Ryan Dahl creates Node.js, combining Google's V8 engine with a event loop and low-level I/O operations
2011
npm (Node Package Manager) is introduced, revolutionizing package management
2015
Node.js Foundation is created, merging Node.js and io.js
2018
Node.js and JS Foundations merge to form OpenJS Foundation
When to Use Node.js
Ideal Use Cases
- Real-time applications (chat, games)
- API development
- Streaming applications
- Microservices architecture
- Command-line tools
Less Ideal Use Cases
- CPU-intensive operations
- Heavy server-side computation
- Traditional relational database operations
Feature Matrix
| Feature | Node.js | Python | PHP | Java |
|---|---|---|---|---|
| Asynchronous by Default | ✅ | ❌ | ❌ | ❌ |
| Package Manager | npm/yarn | pip | composer | maven |
| Learning Curve | Moderate | Easy | Easy | Steep |
| Performance | High | Moderate | Moderate | High |
| Enterprise Support | Good | Excellent | Good | Excellent |
Quick Start Guide
// First Node.js program
const http = require('http');
const server = http.createServer((req, res) => {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
});
server.listen(3000, 'localhost', () => {
console.log('Server running at http://localhost:3000/');
});
Installation
Download Node.js from nodejs.org
# Verify installation node --version npm --version
Cost Considerations
Hobby Applications
- Free to use and distribute
- Free hosting options (Heroku, Vercel, Netlify)
- Low resource requirements
Commercial Use
- No licensing fees
- Cloud hosting costs vary (AWS, Google Cloud, Azure)
- Developer salary considerations
- Enterprise support available
Glossary of Terms
- Event Loop
- The mechanism that allows Node.js to perform non-blocking I/O operations despite JavaScript being single-threaded.
- npm (Node Package Manager)
- The default package manager for Node.js, allowing you to install and manage project dependencies.
- Package.json
- A file that contains metadata about a Node.js project and its dependencies.
- Middleware
- Functions that have access to the request and response objects in an application's request-response cycle.
- Express.js
- A minimal and flexible Node.js web application framework that provides a robust set of features.
- Callback
- A function passed as an argument to another function, which is executed after the main function has finished its execution.
- Promise
- An object representing the eventual completion (or failure) of an asynchronous operation.
- Async/Await
- Syntactic sugar built on top of promises, making asynchronous code easier to write and understand.