🔶 Polymorphism (পলিমরফিজম)

class Person {
  getSleep() {
    console.log(`I am sleeping for 8 hours per day`);
  }
}
 
class Student extends Person {
  getSleep() {
    console.log(`I am sleeping for 7 hours per day`);
  }
}
 
class Developer extends Person {
  getSleep() {
    console.log(`I am sleeping for 6 hours per day`);
  }
}
 
const getSleepingHours = (param: Person) => {
  param.getSleep(); // কোন ক্লাসের instance দিচ্ছো, তার উপর নির্ভর করবে
}
 
const karim = new Person();
const rahim = new Student();
const hasan = new Developer();
 
getSleepingHours(karim);   // I am sleeping for 8 hours per day
getSleepingHours(rahim);   // I am sleeping for 7 hours per day
getSleepingHours(hasan);   // I am sleeping for 6 hours per day

class Shape {
  getArea(): number {
    return 0;
  }
}
 
class Circle extends Shape {
  constructor(public radius: number) {
    super();
  }
  getArea(): number {
    return Math.PI * this.radius * this.radius;
  }
}
 
class Reactangle extends Shape {
  constructor(public height: number, public width: number) {
    super();
  }
  getArea(): number {
    return this.height * this.width;
  }
}
 
const getShapeArea = (shape: Shape) => {
  console.log(shape.getArea());
}
 
const round = new Circle(5);
const box = new Reactangle(10, 20);
 
getShapeArea(round); // 78.54...
getShapeArea(box);   // 200