Classes

1. Welcome and Icebreaker:

• If you could design a class to represent any real-world object, what would it be and what properties would it have?

2. Outline the Session:

• We’ll learn about classes in TypeScript: how to define them, add properties and methods, and use constructors.
• Learning Outcomes: Understand how to create and use classes as blueprints for objects.
• Let’s get object-oriented!

3. Concept Explanation:

• Classes are blueprints for creating objects with specific properties and methods.
• In TypeScript, classes can have typed properties, methods, and constructors.
• Syntax:

  class Person {
    name: string;
    constructor(name: string) {
      this.name = name;
    }
    greet() {
      console.log(`Hello, my name is ${this.name}`);
    }
  }
  

• Classes can also have access modifiers (public, private, protected) and can implement interfaces.

4. Live Coding Demonstration:

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

const dog = new Animal("Buddy");
dog.speak(); // Buddy makes a sound.

class Dog extends Animal {
  breed: string;
  constructor(name: string, breed: string) {
    super(name);
    this.breed = breed;
  }
  speak() {
    console.log(`${this.name} barks!`);
  }
}

const beagle = new Dog("Max", "Beagle");
beagle.speak(); // Max barks!

5. Tasks:

• Short Exercise:
  1. Create a class Book with properties: title (string), author (string), and year (number).
  2. Add a method getSummary that returns a string summary of the book.
  3. Create an instance of Book and print its summary.
  4. Extend Book with a subclass EBook that adds a fileSize property (number, in MB) and overrides getSummary to include the file size.