javascript-no-inheritance-fud.js

(function () {
  function Animal() {}

  Object.defineProperties(Animal.prototype, {
    noise: {
      configurable: false,
      enumerable: false,
      value: null,
      writable: false
    }
  });

  Animal.prototype.makeNoise = function () {
    throw new Error('You must override this method.');
  };

  function Dog() {
    Animal.call(this);
  }

  Dog.prototype = Object.create(Animal.prototype);

  Object.defineProperties(Dog.prototype, {
    noise: {
      configurable: false,
      enumerable: false,
      value: 'woof',
      writable: false
    }
  });

  Dog.prototype.constructor = Dog;

  Dog.prototype.makeNoise = function () {
    console.log(this.noise + '!');
  };

  var snoopy = new Dog();

  if (snoopy instanceof Animal) {
    console.log('snoopy is an instance of Animal.');
  }

  if (snoopy instanceof Dog) {
    console.log('snoopy is an instance of Dog.');
  }

  snoopy.makeNoise();
}).call(this);