Hackerrank | 10 Days of Javascript | Day 5-Solution in JS | Inheritance-hackerrank-Solution-in-JS

Hackerrank | 10 Days of Javascript | Day 5-Solution in JS | Inheritance-hackerrank-Solution-in-JS

Objective

In this challenge, we practice implementing inheritance and use JavaScript prototypes to add a new method to an existing prototype. Check out the attached Classes tutorial to refresh what we've learned about these topics.

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.

https://www.hackerrank.com/challenges/js10-inheritance/problem

Day 5: Inheritance Solution in JS

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);
}

/*
 * Create a Square class that inherits from Rectangle and implement its class constructor
 */
class Square extends Rectangle {
    constructor(s) {
        super(s, 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);
}