JS: revealing module pattern - accessing internal objects vs arrays?

Question

Using the revealing module pattern, how can I provide direct access to non-static private variables? Here's what I have:

var M = function () {
    var obj = {};
    var arr = [];
    var change = function () {
        obj = {"key":"if I see this, O is a reference to obj"};
        arr.push("If I see this, A is a reference to arr")
        };
    return {
        change: change,
        O: obj,
        A: arr
        };
}();

M.change();
console.log(M.A); // prints ["If I see this, A is a reference to arr"] 
console.log(M.O); // prints Object {}, wanted "if I see this, O..."

It seems that A references arr directly, while O settles for a copy of obj's value at initialization time. I would understand the behavior if obj were a string, float, or boolean.

I could of course expose obj via a public get_obj method, but I'm still curious if this can be solved without additional help methods (I want to keep the interface to obj intact). Furthermore, what's so special about arrays that objects don't have, that causes this behavior?

Really grateful for any insights,

In change, you're re-setting value of the obj variable, but modifying the arr variable in place. M.A and M.O are references to the values that arr and obj held at that point. Changing the value of the obj and arr variables doesn't affect M. There's no copying done. Maybe you meant to do obj.key = "if I see this...";. If you want to reset the whole obj and only have one key/value pair in it, you can loop through it and delete properties, then use .key = "if I see this..." — Ian
– Ian, Commented Jul 25, 2013 at 17:21
Ah, I see, and changing O.key did the trick. In my original code I had 'O = d3.layout.force()' which is quite a complex object... =/ — o-o
– o-o, Commented Jul 25, 2013 at 18:53

vsr · Accepted Answer · 2013-07-25 17:36:26Z

1

obj["key"] = "if I see this, O is a reference to obj";

You can set the key property for obj and keep the reference to the original object.

answered Jul 25, 2013 at 17:36

vsr

3,2281 gold badge21 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

JS: revealing module pattern - accessing internal objects vs arrays?

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related