// Before:
function processOrder(order) {
  // 50 lines of code
}

// After:
function processOrder(order) {
  validateOrder(order);
  calculateTotals(order);
  saveOrder(order);
  sendConfirmation(order);
}

// Before:
class UserService {
  async validateEmail(email) {
    if (!email || !email.includes('@')) return false;
    const domain = email.split('@')[1];
    return domain.length > 0;
  }
}
class AdminService {
  async validateEmail(email) {
    if (!email || !email.includes('@')) return false;
    const domain = email.split('@')[1];
    return domain.length > 0;
  }
}

// After:
class EmailValidator {
  async validate(email) {
    if (!email || !email.includes('@')) return false;
    return email.split('@')[1].length > 0;
  }
}

// Before:
class User {
  // Authentication
  // Profile management
  // Notifications
  // Reporting
}

// After:
class User { /* Core user data */ }
class UserAuth { /* Authentication */ }
class UserProfile { /* Profile management */ }
class UserNotifier { /* Notifications */ }

// Before:
function createUser(name, email, age, address, phone, role) { ... }

// After:
function createUser(user: UserData) { ... }

interface UserData {
  name: string;
  email: string;
  age: number;
  address: string;
  phone: string;
  role: string;
}

// Before:
class Order {
  calculatePrice(customer) {
    const discount = customer.getDiscountLevel();
    // ...
  }
}

// After:
class Customer {
  calculatePriceForOrder(order) {
    const discount = this.discountLevel;
    // ...
  }
}

// Before:
function drawShape(x, y, width, height) { ... }
function moveShape(x, y, width, height, dx, dy) { ... }

// After:
class Rectangle {
  constructor(x, y, width, height) { ... }
}
function drawShape(rect: Rectangle) { ... }

// Before:
function createUser(name, email, phone) { ... }

// After:
class Email {
  constructor(value) {
    if (!this.isValid(value)) throw new Error('Invalid email');
    this.value = value;
  }
  // ...
}

// Before:
function calculatePay(employee) {
  switch (employee.type) {
    case 'engineer': return employee.salary * 1.2;
    case 'manager': return employee.salary * 1.5;
    case 'sales': return employee.salary * 1.1;
  }
}

// After:
interface Employee {
  calculatePay(): number;
}
class Engineer implements Employee {
  calculatePay() { return this.salary * 1.2; }
}

// Before:
class User {
  calculateRefund() {
    this.tempRefundAmount = 0;
    // complex calculation
    return this.tempRefundAmount;
  }
}

// After:
class RefundCalculator {
  calculate(user) {
    // ...
  }
}

// Before:
// Calculate the total price including discounts
// and tax based on user location
function calc(u, i) {
  let t = 0;
  // discount logic
  if (u.vip) t *= 0.9;
  // tax logic
  if (u.state === 'CA') t *= 1.08;
  return t;
}

// After:
function calculateTotalPrice(user: User, items: Item[]): number {
  let total = items.sum(i => i.price);
  if (user.isVIP) {
    total = applyVIPDiscount(total);
  }
  return applyTax(total, user.state);
}