Object Literals and Properties in JavaScript

const counter = {
  count: 0,
  
  // Regular method - 'this' refers to counter object
  incrementRegular() {
    this.count++;
    return this.count;
  },
  
  // Arrow function - 'this' doesn't refer to counter object
  incrementArrow: () => {
    // this.count++; // This would not work as expected!
    // 'this' refers to outer scope, not the object
  },
  
  // Using arrow functions inside regular methods works fine
  incrementMultiple(times) {
    // 'this' works here because we're in a regular method
    const numbers = Array.from({length: times}, (_, i) => i + 1);
    numbers.forEach(() => {
      this.count++; // Arrow function inherits 'this' from incrementMultiple
    });
    return this.count;
  }
};

console.log(counter.incrementRegular()); // 1
console.log(counter.incrementMultiple(5)); // 6
console.log(counter.count); // 6

// Shopping cart object (real-life example)
const cart = {
  // Array to store all items added to the cart
  items: [],

  // Tax rate (10%)
  taxRate: 0.1,

  // Method to add an item to the cart
  addItem(name, price) {
    // Add a new item object into the items array
    this.items.push({ name, price });

    // Display confirmation message
    console.log(`${name} added to cart`);
  },

  // Method to calculate total price including tax
  getTotal() {
    let total = 0; // Variable to store subtotal

    // Loop through each item in the cart
    for (let item of this.items) {
      // Add item price to total
      total += item.price;
    }

    // Calculate tax amount
    const tax = total * this.taxRate;

    // Return final total (subtotal + tax)
    return total + tax;
  }
};

// Object - Named properties
const userObject = {
  id: 101,
  name: 'Emma Wilson',
  email: 'emma@example.com',
  age: 28
};

console.log(userObject.name); // Access by property name: 'Emma Wilson'

// Array - Indexed elements
const userArray = [101, 'Emma Wilson', 'emma@example.com', 28];

console.log(userArray[1]); // Access by index: 'Emma Wilson'
// Problem: What does index 1 represent? Not immediately clear!

// User profile - single entity with multiple attributes
const userProfile = {
  username: 'john_dev',
  email: 'john@example.com',
  role: 'developer',
  permissions: ['read', 'write', 'execute'],
  preferences: {
    theme: 'dark',
    language: 'en',
    notifications: true
  },
  lastLogin: new Date('2024-01-15')
};

// Product details - named properties provide clarity
const product = {
  sku: 'LAP-2024-001',
  name: 'Pro Laptop',
  price: 1299.99,
  category: 'Electronics',
  inStock: true,
  specifications: {
    processor: 'Intel i7',
    ram: '16GB',
    storage: '512GB SSD'
  }
};

// Application configuration
const appConfig = {
  apiBaseUrl: 'https://api.example.com',
  timeout: 5000,
  retryAttempts: 3,
  enableLogging: true,
  features: {
    darkMode: true,
    notifications: false,
    analytics: true
  }
};

// Database query result - single record
const blogPost = {
  id: 42,
  title: 'Understanding JavaScript Objects',
  author: 'Jane Smith',
  publishDate: '2024-01-10',
  content: 'Full article content here...',
  tags: ['javascript', 'programming', 'tutorial'],
  views: 1523,
  likes: 89
};

// List of users - multiple similar entities
const users = [
  { id: 1, name: 'Alice', role: 'admin' },
  { id: 2, name: 'Bob', role: 'user' },
  { id: 3, name: 'Charlie', role: 'user' }
];

// Shopping list - ordered collection
const shoppingList = [
  'Milk',
  'Eggs',
  'Bread',
  'Butter',
  'Coffee'
];

// Scores - order matters (chronological or ranking)
const testScores = [95, 87, 92, 78, 88];

// Todo items - list that will be iterated
const todos = [
  { id: 1, task: 'Buy groceries', completed: false },
  { id: 2, task: 'Pay bills', completed: true },
  { id: 3, task: 'Call dentist', completed: false }
];

// Coordinates - ordered numeric data
const coordinates = [40.7128, -74.0060]; // [latitude, longitude]

// History or timeline - chronological order matters
const loginHistory = [
  { timestamp: '2024-01-15T10:30:00', ip: '192.168.1.1' },
  { timestamp: '2024-01-15T14:22:00', ip: '192.168.1.1' },
  { timestamp: '2024-01-16T09:15:00', ip: '10.0.0.5' }
];

const numbers = [1, 2, 3, 4, 5];

// Filter - get even numbers
const evenNumbers = numbers.filter(num => num % 2 === 0);
console.log(evenNumbers); // [2, 4]

// Map - double each number
const doubled = numbers.map(num => num * 2);
console.log(doubled); // [2, 4, 6, 8, 10]

// Reduce - sum all numbers
const sum = numbers.reduce((total, num) => total + num, 0);
console.log(sum); // 15

// Find - get first number greater than 3
const found = numbers.find(num => num > 3);
console.log(found); // 4

// Sort - arrange in descending order
const sorted = [...numbers].sort((a, b) => b - a);
console.log(sorted); // [5, 4, 3, 2, 1]

// ForEach - iterate through items
numbers.forEach((num, index) => {
  console.log(`Index ${index}: ${num}`);
});

const students = [
  {
    id: 1,
    name: "Rahul",
    subject: "Math",
    marks: 85
  },
  {
    id: 2,
    name: "Priya",
    subject: "Science",
    marks: 92
  },
  {
    id: 3,
    name: "Aman",
    subject: "English",
    marks: 78
  }
];

// Accessing data
console.log(students[0].name);    // Rahul
console.log(students[1].marks);   // 92