Classes

        
          // Class with type annotations
class Person {
  // Property types
  name: string;
  private age: number;
  protected email: string;

  // Constructor
  constructor(name: string, age: number, email: string) {
    this.name = name;
    this.age = age;
    this.email = email;
  }

  // Method
  greet(): string {
    return `Hello, I'm ${this.name}`;
  }

  // Getter/Setter
  get isAdult(): boolean {
    return this.age >= 18;
  }

  set updateAge(newAge: number) {
    if (newAge >= 0) {
      this.age = newAge;
    }
  }

  // Static method
  static createAnonymous(): Person {
    return new Person("Anonymous", 0, "anonymous@example.com");
  }
}

// Inheritance
class Employee extends Person {
  jobTitle: string;
  salary: number;

  constructor(name: string, age: number, email: string, jobTitle: string, salary: number) {
    super(name, age, email);
    this.jobTitle = jobTitle;
    this.salary = salary;
  }

  work(): string {
    return `${this.name} is working as ${this.jobTitle}`;
  }

  // Method override
  greet(): string {
    return `${super.greet()} and I work as ${this.jobTitle}`;
  }
}

// Abstract classes
abstract class Shape {
  abstract getArea(): number;

  getDescription(): string {
    return `Area: ${this.getArea()}`;
  }
}

class Rectangle extends Shape {
  constructor(private width: number, private height: number) {
    super();
  }

  getArea(): number {
    return this.width * this.height;
  }
}

// Usage
const person = new Person("John", 25, "john@example.com");
const employee = new Employee("Jane", 30, "jane@example.com", "Developer", 75000);
const rect = new Rectangle(10, 20);

console.log(person.greet()); // Hello, I'm John
console.log(employee.greet()); // Hello, I'm Jane and I work as Developer
console.log(rect.getArea()); // 200