inheritance || JS hackerrank Solution

 Task

We provide the implementation for a Rectangle class in the editor. Perform the following tasks:

1. Add an area method to Rectangle's prototype.

2. Create a Square class that satisfies the following:

It is a subclass of Rectangle.

It contains a constructor and no other methods.

It can use the Rectangle class' area method to print the area of a Square object.

Locked code in the editor tests the class and method implementations and prints the area values to

STDOUT.

   

Solution:

class Rectangle {     constructor(w, h) {         this.w = w;         this.h = h;     }   }     Rectangle.prototype.area=function(){     return (this.h*this.w);    }        class Square extends Rectangle{     constructor(s){         super(s);                 this.w=s;         this.h=s;               }        }       if (JSON.stringify(Object.getOwnPropertyNames(Square.prototype))   === JSON.stringify([ 'constructor' ])) {     const rec = new Rectangle(3, 4);     const sqr = new Square(3);         console.log(rec.area());     console.log(sqr.area());     } else {     console.log(-1);     console.log(-1);     }