Day 5: Inheritance | 10 Days Of JavaScript | HackerRank Solution

Hello coders, today we are going to solve Day 5: Inheritance HackerRank Solution which is a part of 10 Days of JavaScript Series.

Objective

In this challenge, we practice implementing inheritance and use JavaScript prototypes to add a new method to an existing prototype.

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 – Day 5: Inheritance

class Rectangle {
    constructor(w, h) {
        this.w = w;
        this.h = h;
    }
}

/*
 *  Write code that adds an 'area' method to the Rectangle class' prototype
 */
 Rectangle.prototype.area = function() {
     return (this.w * this.h);
 }
 class Square extends Rectangle {
     constructor(w){
         super(w, w);
     }
 }
/*
 * Create a Square class that inherits from Rectangle and implement its class constructor
 */


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);
}

Disclaimer: The above Problem (Inheritance) is generated by Hacker Rank but the Solution is provided by CodingBroz. This tutorial is only for Educational and Learning Purpose.