CODEWITHSUNDEEP
javascriptobjectgarbage-collectiondispose
blow
blow

Reputation: 13209

Javascript: know when an object will be garbaged

is there a way to know when an object will be disposed by GC?

My object (call it A) write some variables in a global array-object, so when the object will be garbaged its own variable will stay in the global array-object, taking up memory.

ps. i have numerous objects A and i prefer to not call "manually" a method to free my global array-object.

This is my situation:

var global_array=[];

function A(x){
    global_array.push({who:"A", what:x, id:A.instance++});
    this.x=x;
}
A.instance=0;
A.prototype.useIt=function(){
    return this.x*2;
}

//will be created an A object and will be garbaged after use by GC
function test(){
    var a=new A(10);
    var y=a.useIt();
}

test();
//i will never use <a> object again, but global_array hold {who:"A", what:10, id:0)}

DO NOT WANT

A.prototype.dispose=function(){
    // free global_array at the correct index
}

Thanks.

Upvotes: 0

Views: 2300

Answers (2)

MaLKaV_eS
MaLKaV_eS

Reputation: 1325

And what about clearing it from globla_array at the end of test method? As you are saying it won't be used anymore, it will be safe to clear that info.

EDIT: In response to your comment (as I think I can't get it clearly stated), let's asume you can get to know when object A is gc:

function objectGetGC(sender)
{
    // You still have to implement here how to clear global_array from object data
    // javascript won't know how to do it on its own.
}

If global_array holds a reference to object A, instead of only data, it won't be gc...

Hope that now is a bit clear what I mean.

Upvotes: 0

Tim Down
Tim Down

Reputation: 324627

I'm not exactly sure what the question is, but I can tell you this:

  1. You can't tell exactly when an object will be garbage collected

  2. An object cannot be garbage collected until all references to it have been deleted, so keeping a reference to an object in an array stored in a global variable will ensure that it isn't garbage collected until the page unloads.

Upvotes: 2

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