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Classes and Object-Oriented Programming

Beginner
100 XP
40 min
Lesson Content

Classes in TypeScript

TypeScript classes support access modifiers and are essential for Angular and object-oriented programming.

Basic Class

class Person {
  name: string;
  age: number;
  
  constructor(name: string, age: number) {
    this.name = name;
    this.age = age;
  }
  
  greet(): string {
    return `Hello, I'm ${this.name}`;
  }
}

Access Modifiers

class BankAccount {
  public balance: number; // Accessible everywhere
  private accountNumber: string; // Only inside class
  protected owner: string; // Accessible in subclasses
}

Inheritance

class Animal {
  constructor(public name: string) {}
  
  speak(): void {
    console.log(`${this.name} makes a sound`);
  }
}

class Dog extends Animal {
  speak(): void {
    console.log(`${this.name} barks`);
  }
}
Example Code

Create classes with properties and methods

class Rectangle {
  width: number;
  height: number;
  
  constructor(width: number, height: number) {
    this.width = width;
    this.height = height;
  }
  
  getArea(): number {
    return this.width * this.height;
  }
}

const rect = new Rectangle(5, 10);
console.log(`Area: ${rect.getArea()}`);

Expected Output:

Area: 50
Study Tips
  • •Read the theory content thoroughly before practicing
  • •Review the example code to understand key concepts
  • •Proceed to the Practice tab when you're ready to code