Javascript nested object access root level

Question

I have a nested object in javascript like this one:

{
nameRoot: "my object",
sub: {
  nameSub: "my sub object"
}
}

I want to access nameRoot from a function defined in sub.

Using a function i would have defined something like:

var self = this;

and used self but how can I do this in a literal object?

I don't believe you can. I don't know of the post off the top of my head, but I remember reading this on StackOverflow recently. Can you define that object as a function, instead of an object literal? — Brad
– Brad, Commented Aug 29, 2012 at 14:26
You can’t. But an object is not without reference, so somewhere you must have a reference to the object you are in, no? — David Hellsing
– David Hellsing, Commented Aug 29, 2012 at 14:33
This is also the reason why nodes and such need to have an explicit reference back to parentNode. — voithos
– voithos, Commented Aug 29, 2012 at 14:46

ChaosPandion · Accepted Answer · 2012-08-29 15:03:32Z

2

The following code allows you to link to a parent element and avoid the parent showing up in a for-in loop.

var parent = { a: 1 };
var child = { b: 2 };

Object.defineProperty(
    child, 'parent', 
    { value: parent, 
      enumerable: false }
);

parent.child = child;

child.performAction = function() {
    console.log(this.parent.a) // 1
}

answered Aug 29, 2012 at 15:03

ChaosPandion

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Comments

Paul · Accepted Answer · 2012-08-29 14:48:26Z

0

So the best way to do this is w/ function scope.

function myFunc(){
   this.nameRoot = "my object";
}

then you could do something like:

var func = new myFunc();
func.sub = new myFunc();
func.sub.nameRoot = "my sub object";

Obviously there are smarter ways to do it (e.g. pass the name through the function params) but this is the general pattern.

answered Aug 29, 2012 at 14:48

Paul

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2 Comments

Andrew D. Over a year ago

Question: but how can I do this in a "literal object"

Paul Over a year ago

You can't, that's why I said to do it the way I suggested.

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