Prototypal class object creator

dogPrototypalClass.js

var Dogs = function (name, breed, age, happiness, hunger, energy){
  var dog = Object.create(Dogs.prototype)
  dog.name = name;
  dog.breed = breed;
  dog.age = age;
  dog.happiness : happiness;
  dog.hunger = hunger;
  dog.energy = energy;
  return dog;
}
  Dogs.prototype.feed = function(food){
    if(this.hunger - food > 0) {
      this.hunger -= food;
    } else {
      this.hunger = 0;
    }
  };

  Dogs.prototype.play = function(time){
    if(this.happiness + time < 100) {
      this.happiness += time;
    } else {
      this.happiness = 100;
  } 

    if(this.energy - time > 0) {
      this.energy -= time;
    } else {
      this.energy = 0;
    }
  };

  Dogs.prototype.nap = function(time) {
    if(this.energy + time < 100) {
      this.energy += time;
    } else {
      this.energy = 100;
    }
  };