Accessing closures in setTimeout

[sloLearner]

Hi - I wonder if anyone can help me with something that's been bugging me for a long time. When writing JS, I try to encapsulate my code somehow. For instance, in the example below, I have a function ('testFunc') that's encapsulated within jQuery's document.ready callback function :

$(function(){
		var testFunc = function(x){
			x++;
			return x;	
		}
});

If I then start using JS's base timer functions like settimeout, I've always been unsure of how to access the 'testFunc' function. As I understand it, even if the timer functions are called inside the same function, as in...

$(function(){
		var testFunc = function(x){
			x++;
			return x;	
		}
		
		var timer = setTimeout("testFunc", 100);
});

... they will lose the scope of the jQuery callback - instead the timer functions will only be able to access objects in the global scope.

Does anyone have any ideas/advice on best practise for how to solve this kind of problem?

Thanks for any help!

Nick

[Kor]

But you have sent no argument to that function. Maybe you wanted something like

var arg=1;
var that=this;
var timer = setTimeout(function(){that.testFunc(arg)), 100);

or something like that

[sloLearner]

Doh! Thanks for your reply. Sorry, I did indeed forget to send an argument...

Will experiment with your suggestion..!

[sloLearner]

Hi - am afraid I couldn't get that last suggestion to work. If anyone's interested however, I 'think' I've got something reasonably simple to work, using the Singleton pattern. I don't know if it's a bit over the top, but it seems to work...

var NSD = (function() {
	return {
		testFunc: function(x){
			x++;
			document.write (x);
		},
		onload: $(function(){
		var a = setTimeout('NSD.testFunc(1)', 1000);			
		})
	}
})();

'NSD' here is just a namespace used to encapsulate all my functions. Because 'testFunc' is now a public function (note, not a global one), the 'setTimeout' function can access it.

You can probably tell I'm just experimenting - I'm sure there are more elegant ways of doing this, so any suggestions are welcome!!

[Kor]

My suggestion was otherwise. Try:

var a = setTimeout(function(){NSD.testFunc(1)}, 1000);

[sloLearner]

Thanks - yes, I should write it using the anonymous function as you suggest