JS prototype inheritance pattern examples

Dog.js

// https://medium.com/@PitaJ/javascript-inheritance-patterns-179d8f6c143c#.36nqv16pb
// Object.create, top-level factory, prototype post-declaration

function Animal(type){
  var animal = Object.create(Animal.prototype);
  animal.type = type;
  return animal;
}
Animal.isAnimal = function(obj, type){
  if(!Animal.prototype.isPrototypeOf(obj)){
    return false;
  }
  return type ? obj.type === type : true;
};
Animal.prototype = {};
function Dog(name, breed){
  var dog = Object.create(Dog.prototype);
  Object.assign(dog, Animal("dog"));
  dog.name = name;
  dog.breed = breed;
  return dog;
}
Dog.isDog = function(obj){
  return Animal.isAnimal(obj, "dog");
};
Dog.prototype = {
  bark(){
    console.log("ruff, ruff");
  },
  print(){
    console.log("The dog " + this.name + " is a " + this.breed);
  }
};
Object.setPrototypeOf(Dog.prototype, Animal.prototype);

// https://medium.com/@PitaJ/javascript-inheritance-patterns-179d8f6c143c#.36nqv16pb
// Explicit prototype declaration, Object.create, method factory

var Animal = {
  create(type){
    var animal = Object.create(Animal.prototype);
    animal.type = type;
    return animal;
  },
  isAnimal(obj, type){
    if(!Animal.prototype.isPrototypeOf(obj)){
      return false;
    }
    return type ? obj.type === type : true;
  },
  prototype: {}
};
var Dog = {
  create(name, breed){
    var dog = Object.create(Dog.prototype); 
    Object.assign(dog, Animal.create("dog"));
    dog.name = name;
    dog.breed = breed;
    return dog;
  },
  isDog(obj){
    return Animal.isAnimal(obj, "dog");
  },
  prototype: {
    bark(){
      console.log("ruff, ruff");
    },
    print(){
      console.log("The dog " + this.name + " is a " + this.breed);
    }
  }
};
Object.setPrototypeOf(Dog.prototype, Animal.prototype);