Node.js Brief Board

Overview

• Node.js: Open-source, cross-platform JavaScript runtime for server-side development.

• Built on Chrome's V8 JavaScript engine.

• Non-blocking, event-driven, and highly scalable.

Core Features

1. Asynchronous & Non-blocking: Efficiently handles multiple requests.

2. Event Loop: Single-threaded but manages concurrency effectively.

3. Fast Execution: Powered by the V8 engine.

4. Modular Architecture: Thousands of libraries are available via npm.

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Key Components

• Event Loop: Executes callbacks in phases.

• Libuv: Provides asynchronous I/O and thread pooling.

• Modules: Includes fs, http, path, and more.

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Common Use Cases

• RESTful APIs

• Real-time applications (e.g., chat apps)

• Microservices

• Serverless architectures

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Coding Snippet: HTTP Server

const http = require('http');
const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello, World!');
});
server.listen(3000, () => console.log('Server running on port 3000'));

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Error Handling

1. Synchronous Code: Use try-catch blocks.

2. Async Code:

   • Promises: .catch() for error handling.

   • Async/Await: Wrap in try-catch.

3. Global Errors:

   • uncaughtException for unhandled exceptions.

   • unhandledRejection for rejected Promises.

4. Example:

    try {
      const data = await fetchData();
    } catch (err) {
      console.error('Error:', err.message);
    }
   

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Security

1. Input Validation: Prevent injection attacks using libraries like validator or Joi.

2. HTTPS: Always use encrypted connections.

3. Environment Variables: Secure sensitive data using dotenv.

4. Best Practices:

   • Implement CORS to restrict access.

   • Use helmet to set HTTP headers.

   • Apply rate-limiting to prevent DDoS attacks.

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Performance Optimization

1. Clustering: Utilize multiple CPU cores with the cluster module.

2. Caching:

   • Use tools like Redis to cache data.

   • Avoid repeated database queries.

3. Asynchronous Code: Replace the blocking code with an async operation.

4. Example - Clustering:

    const cluster = require('cluster');
    const os = require('os');
   
    if (cluster.isMaster) {
      const cpuCount = os.cpus().length;
      for (let i = 0; i < cpuCount; i++) cluster.fork();
    } else {
      // Worker logic
      console.log(`Worker ${process.pid} started`);
    }
   

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Package Management

• npm: Manage dependencies and scripts.

• Key commands: npm install, npm run, npm update.

• Central file: package.json (metadata and dependencies).

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Advantages

• High performance for I/O-bound tasks.

• A huge ecosystem of libraries via npm.

• Easy to learn for JavaScript developers.

Limitations

• Not ideal for CPU-intensive tasks.

• Callback hell (mitigated with Promises/async-await).

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Further Reading

• Official Node.js Documentation

• npm Package Registry