getting name of object part of prototype chain

Question

I have a simple prototype chain, and I want to get the name of all prototypes that are a part of it:

function Animal(name, age){
    this.name = name;
    this.age = age;

    this.eat = function(){console.log(name + " eats");}
    this.getAge = function(){console.log(name + " is " + age + " years old");}
}

function Cat(name, age){
    Animal.call(this, name, age);
    this.hunt = function(){console.log(name + " hunts mice")};
}
Cat.prototype = new Animal();

var cat1 = new Cat("cat1", 2);

var currentPrototype = cat1;
while(currentPrototype != null){
    console.log(currentPrototype.constructor.name);
    currentPrototype = Object.getPrototypeOf(currentPrototype);
}

I would expect to get Cat, then Animal, then Object. However, I am getting:

Animal
Animal
Animal
Object

Can someone explain to me why this happens, and how to get the correct result. Is my whole prototype inheritance wrong..?

Answer 1

When you did Cat.prototype = new Animal();, you made

[[prototype]] of Child be a ref to Parent.

This changes the child's constructor pointing to parent.

you need to explicitly set

Cat.prototype.constructor = Cat;

See the below example:

function Animal(name, age){
    this.name = name;
    this.age = age;

    this.eat = function(){console.log(name + " eats");}
    this.getAge = function(){console.log(name + " is " + age + " years old");}
}

function Cat(name, age){
    Animal.call(this, name, age);
    this.hunt = function(){console.log(name + " hunts mice")};
}
Cat.prototype = new Animal();

Cat.prototype.constructor = Cat;
var cat1 = new Cat("cat1", 2);

var currentPrototype = cat1;
while(currentPrototype != null){
    console.log(currentPrototype.constructor.name);
    currentPrototype = Object.getPrototypeOf(currentPrototype);
}