ES6 Classes and Inheritance example (www.es6fiddle.net)

es6-classes-inheritance.js

/**
 * Classes and Inheritance
 * Code Example from http://www.es6fiddle.net/
 */
class Polygon {
  constructor(height, width) { //class constructor
    this.name = 'Polygon';
    this.height = height;
    this.width = width;
  }

  sayName() { //class method
    console.log('Hi, I am a', this.name + '.');
  }
}

class Square extends Polygon {
  constructor(length=10) { // ES6 features Default Parameters
    super(length, length); //call the parent method with super
    this.name = 'Square';
  }

  get area() { //calculated attribute getter
    return this.height * this.width;
  }
}

let s = new Square(5);

s.sayName(); // => Hi, I am a Square.
console.log(s.area); // => 25

console.log(new Square().area); // => 100