Question

I am trying to understand JavaScripts Prototypal nature and I am trying to create object inheritance without using class like constructor functions.

How can I attach the prototype chain from Animals and then each to Cat and Dog if they are all three object literals?

Also, is there a way to do an Object.create and add more properties in literal form (like myCat).

I’ve added the code below & to paste bin http://jsbin.com/eqigox/edit#javascript

var Animal = {
    name        : null,
    hairColor   : null,
    legs        : 4,

    getName : function() {
        return this.name;
    },
    getColor : function() {
        console.log("The hair color is " + this.hairColor);
    }
};

/* Somehow Dog extends Animal */

var Dog = {
    bark : function() {
        console.log("Woof! My name is ");
    }
};

/* Somehow Cat Extends Animal */

var Cat = {
    getName : function() {
        return this.name;
    },

    meow : function() {
        console.log("Meow! My name is " + this.name);
    }
};


/* myDog extends Dog */

var myDog = Object.create(Dog);

/* Adding in with dot notation */
myDog.name = "Remi";
myDog.hairColor = "Brown";
myDog.fetch = function() {
    console.log("He runs and brings back it back");
};


/* This would be nice to add properties in litteral form */
var myCat = Object.create(Cat, {
    name        : "Fluffy",
    hairColor   : "white",
    legs : 3, //bad accident!
    chaseBall : function(){
        console.log("It chases a ball");
    }

});

myDog.getColor();

Answer 1

You can use Object.create to use your defined objects as prototypes. For instance:

var Dog = Object.create(Animal, {
    bark : {
        value: function() {
            console.log("Woof! My name is " + this.name);
        }
    }
});

Now you can create a new Dog object:

var myDog = Object.create(Dog);
myDog.bark();  // 'Woof! My name is null'
myDog.getColor();  // 'The hair color is null'

Example: http://jsfiddle.net/5Q3W7/1/

Alternatively, if you’re working in the absence of Object.create, you can use constructors:

function Animal() {
    this.name = null;
    this.hairColor = null;
    this.legs = 4;
};

Animal.prototype = {
    getName : function() {
        return this.name;
    },
    getColor : function() {
        console.log("The hair color is " + this.hairColor);
    }
}

function Dog() {
}

Dog.prototype = new Animal;
Dog.prototype.bark = function() {
    console.log("Woof! My name is " + this.name);
};

Example: http://jsfiddle.net/5Q3W7/2/

For more information about Object.create: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/create/

For more information about Constructors and prototypes chains:
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/constructor

https://developer.mozilla.org/en/JavaScript/Guide/Inheritance_and_the_prototype_chain