Comparison between ES6 and traditional approach to extending classes

extends.js

// ES6 style
class Gorilla extends Animal {
    constructor(name, weight) {
        super(name, weight);
    }
  //...
}

// Traditional style
function Gorilla(name, weight) {
    Animal.call(this, name, weight);
}

Gorilla.prototype = Object.create(Animal.prototype);
Gorilla.prototype.constructor = Gorilla;
//...