Roadmap

    3 - Class

    Class

    A class is similar to an interface, it provides a blueprint for creating objects with specific properties and methods.

    ts
    // Classes can have a constructor to initialize objects.
     
    class Phone {
      make: string;
      model: string;
      year: number;
     
      constructor(make: string, model: string, year: number) {
        this.make = make;
        this.model = model;
        this.year = year;
      }
     
      drive() {
        console.log(`Calling from my ${this.year} ${this.make} ${this.model}`);
      }
    }

    But, It can also include implementations of properties and methods, and have constructors, inheritance, and access modifiers.

    ts
    class Animal {
      // by using the public keyword we can automatically create properties with the same name as the constructor arguments
      constructor(public name: string, public age: number) {}
     
      //Classes can define methods with implementations
      public getAge(): number {
        return this.age;
      }
    }
     
    // Classes can extend other classes to inherit properties and methods.
     
    class Dog extends Animal {
      // By using private keyword, we can restrict access to the owner property
      constructor(
        name: string,
        age: number,
        public breed: string,
        private owner?: string
      ) {
        super(name, age);
      }
     
      public introduce(): void {
        console.log(`${this.name} is a ${this.age} yr old ${this.breed}`);
      }
    }
     
    const dog = new Dog("Buddy", 5, "Golden Retriever");
     
    dog.introduce(); // Buddy is a 5 yr old Golden Retriever

    Differences Between Interface and Class

    Interface is used to define the shape of an object, primarily for type-checking. It does not provide implementations for properties and methods.

    Class is Used to create objects with specific properties and methods, and can provide implementations for properties and methods.