Destructuring

        
          // 1. ARRAY DESTRUCTURING
const numbers = [10, 20, 30, 40, 50];

// Basic destructuring
const [first, second] = numbers;
console.log(first, second); // 10, 20

// Skip elements
const [, , third] = numbers;
console.log(third); // 30

// Rest operator for remaining elements
const [head, ...tail] = numbers;
console.log(head, tail); // 10, [20, 30, 40, 50]

// Default values
const [a = 1, b = 2, c = 3] = [100];
console.log(a, b, c); // 100, 2, 3

// Swapping variables (no temporary variable needed!)
let x = 1, y = 2;
[x, y] = [y, x];
console.log(x, y); // 2, 1

// 2. OBJECT DESTRUCTURING
const user = {
  name: 'Alice',
  age: 28,
  job: 'Designer',
  location: {
    city: 'New York',
    country: 'USA'
  },
  hobbies: ['reading', 'coding', 'gaming']
};

// Basic destructuring
const { name, age } = user;
console.log(name, age); // Alice, 28

// Renaming variables
const { name: userName, job: profession } = user;
console.log(userName, profession); // Alice, Designer

// Default values
const { salary = 50000, department = 'General' } = user;
console.log(salary, department); // 50000, General

// Nested destructuring
const { location: { city, country } } = user;
console.log(city, country); // New York, USA

// 3. ADVANCED PATTERNS
// Destructuring function parameters
function createUser({ name, age, email, ...otherProps }) {
  return {
    id: Date.now(),
    name: name || 'Anonymous',
    age: age || 18,
    email: email || 'no-email@example.com',
    ...otherProps
  };
}

const newUser = createUser({
  name: 'Bob',
  age: 25,
  email: 'bob@example.com',
  department: 'Engineering'
});
console.log(newUser);

// Destructuring in loops
const users = [
  { id: 1, name: 'Alice', role: 'admin' },
  { id: 2, name: 'Bob', role: 'user' },
  { id: 3, name: 'Charlie', role: 'moderator' }
];

for (const { id, name, role } of users) {
  console.log(`${name} (${id}) is a ${role}`);
}

// 4. PRACTICAL EXAMPLES
// API Response handling
function processApiResponse(response) {
  const {
    data: {
      user: { name, email },
      posts = []
    },
    status,
    message
  } = response;

  if (status !== 'success') {
    throw new Error(message);
  }

  return { user: { name, email }, posts };
}

// React component props (concept)
function UserCard({ user: { name, avatar }, onClick, className = '' }) {
  return `<div class="${className}" onclick="${onClick}">
    <img src="${avatar}" alt="${name}'s avatar">
    <h3>${name}</h3>
  </div>`;
}

// Configuration object
const config = {
  server: { host: 'localhost', port: 3000 },
  database: { url: 'mongodb://localhost:27017' },
  features: { auth: true, logging: false }
};

const {
  server: { host, port },
  database: { url: dbUrl },
  features: { auth: isAuthEnabled, logging: isLoggingEnabled }
} = config;

console.log(`Server: ${host}:${port}`);
console.log(`Database: ${dbUrl}`);
console.log(`Auth enabled: ${isAuthEnabled}`);

// 5. DESTRUCTURING WITH REGEX MATCHES
const url = 'https://www.example.com/path?param=value';
const regex = /^https?:\/\/([^/?#]+)([^?#]*)/;
const [, domain, path] = url.match(regex) || [];
console.log(domain, path); // www.example.com, /path

// 6. MIXED DESTRUCTURING
const mixedData = {
  items: [
    { id: 1, title: 'First' },
    { id: 2, title: 'Second' }
  ],
  metadata: {
    total: 2,
    page: 1
  }
};

const {
  items: [firstItem, secondItem],
  metadata: { total, page }
} = mixedData;

console.log(firstItem.title, total); // First, 2

// 7. DESTRUCTURING IN RETURN STATEMENTS
function getCoordinates() {
  return { x: 10, y: 20, z: 30 };
}

const { x, y } = getCoordinates();
console.log(x, y); // 10, 20

// 8. COMPUTED PROPERTY NAMES (Advanced)
const dynamicKey = 'theme';
const settings = {
  [dynamicKey]: 'dark',
  language: 'en',
  notifications: true
};

const { [dynamicKey]: selectedTheme, ...otherSettings } = settings;
console.log(selectedTheme, otherSettings); // dark, { language: 'en', notifications: true }