Javascript inheritence of child object on prototype

Question

I am just starting to learn prototype inheritance in JS and I would like the child object (def2) of my subclass object to inherit from superclass object's child object (def). The following code will explain what I mean:

function Animal(name)
{
    this.name = name;       
    this.def = {
        FieldA: 'aaa',
        FieldB: 'bbb'
    }
}

function Rabbit(name, category)
{
    Animal.apply(this, arguments);  

    this.def2 = { };        
    this.def2.prototype = Animal.def;       
    alert(this.def2.FieldA);  // this is undefined 

}

you would have to say this.def2 = new Animal(name). if you use prototype, you use "new ". — dandavis, Nov 06 '13 at 21:56
I dont want def2 to have properties/methods from Animal, but from Animal.def — BlueChameleon, Nov 06 '13 at 21:57

megawac · Accepted Answer · 2013-11-06T22:07:19.000

1

function Rabbit(name, category) {
    Animal.apply(this, arguments);
    this.def2 = clone(this.def); //where clone is a function similar to http://stackoverflow.com/questions/122102/most-efficient-way-to-clone-an-object#answer-122190   

    alert(this.def.FieldA);  // this is 'aaa'
}
Rabbit.prototype = new Animal(); //inherit Animal
Rabbit.prototype.constructor = Rabbit;

I suggest you read http://phrogz.net/JS/classes/OOPinJS2.html or a similar article

edited Nov 06 '13 at 22:07

answered Nov 06 '13 at 22:00

megawac

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Ok, but now in rabbit i want to define another object called def2, which should inherit properties of Animal.def. How do I do this? – BlueChameleon Nov 06 '13 at 22:01
is Animal.def always going to be an object say defaults? – megawac Nov 06 '13 at 22:03
Then clone it - not sure why you want to clone it though. I'll update my code – megawac Nov 06 '13 at 22:04
with $.extend() right? I was thinking about cloning, but for some reason didnt go that path – BlueChameleon Nov 06 '13 at 22:06
Yes, `jQuery.clone(this.def)` or `jQuery.extend({}, this.def)` is what you're looking for I believe – megawac Nov 06 '13 at 22:08

Javascript inheritence of child object on prototype

1 Answers1