Node.js Development

// Simple HTTP Server
const http = require('http');

const server = http.createServer((req, res) => {
  res.writeHead(200, { 'Content-Type': 'text/html' });
  res.end('<h1>Hello from Node.js! 🚀</h1>');
});

const PORT = 3000;
server.listen(PORT, () => {
  console.log(`🌟 Server running at http://localhost:${PORT}`);
});

// Run with: node server.js

const express = require('express');
const app = express();

// Middleware to parse JSON
app.use(express.json());

// Sample data
let users = [
  { id: 1, name: 'Alice', age: 25 },
  { id: 2, name: 'Bob', age: 30 }
];

// GET all users
app.get('/api/users', (req, res) => {
  res.json(users);
});

// GET user by ID
app.get('/api/users/:id', (req, res) => {
  const user = users.find(u => u.id === parseInt(req.params.id));
  if (!user) {
    return res.status(404).json({ message: 'User not found' });
  }
  res.json(user);
});

// POST new user
app.post('/api/users', (req, res) => {
  const newUser = {
    id: users.length + 1,
    name: req.body.name,
    age: req.body.age
  };
  users.push(newUser);
  res.status(201).json(newUser);
});

app.listen(3000, () => {
  console.log('🚀 API server running on port 3000');
});

// fileManager.js - Custom Module
const fs = require('fs').promises;
const path = require('path');

class FileManager {
  constructor(baseDir = './data') {
    this.baseDir = baseDir;
    this.ensureDirectoryExists();
  }

  async ensureDirectoryExists() {
    try {
      await fs.access(this.baseDir);
    } catch {
      await fs.mkdir(this.baseDir, { recursive: true });
      console.log(`📁 Created directory: ${this.baseDir}`);
    }
  }

  async saveData(filename, data) {
    const filePath = path.join(this.baseDir, filename);
    await fs.writeFile(filePath, JSON.stringify(data, null, 2));
    console.log(`💾 Saved data to ${filename}`);
  }

  async loadData(filename) {
    try {
      const filePath = path.join(this.baseDir, filename);
      const data = await fs.readFile(filePath, 'utf8');
      return JSON.parse(data);
    } catch (error) {
      console.log(`❌ Error loading ${filename}:`, error.message);
      return null;
    }
  }

  async deleteFile(filename) {
    try {
      const filePath = path.join(this.baseDir, filename);
      await fs.unlink(filePath);
      console.log(`🗑️ Deleted ${filename}`);
    } catch (error) {
      console.log(`❌ Error deleting ${filename}:`, error.message);
    }
  }
}

// Usage
const fileManager = new FileManager();

// Save some data
fileManager.saveData('users.json', [
  { name: 'Alice', email: 'alice@example.com' },
  { name: 'Bob', email: 'bob@example.com' }
]);

// Load and display data
fileManager.loadData('users.json')
  .then(data => console.log('📖 Loaded users:', data));

module.exports = FileManager;