Mootools - how to destroy a class instance
- by Rob
What I'm trying to do is create a class that I can quickly attach to links, that will fetch and display a thumbnail preview of the document being linked to. Now, I am focusing on ease of use and portability here, I want to simply add a mouseover event to links like this:
<a href="some-document.pdf" onmouseover="new TestClass(this)">Testing</a>
I realize there are other ways I can go about this that would solve my issue here, and I may end up having to do that, but right now my goal is to implement this as above. I don't want to manually add a mouseout event to each link, and I don't want code anywhere other than within the class (and the mouseover event creating the class instance).
The code:
TestClass = new Class({
initialize: function(anchor) {
this.anchor = $(anchor);
if(!this.anchor) return;
if(!window.zzz) window.zzz = 0;
this.id = ++window.zzz;
this.anchor.addEvent('mouseout', function() {
// i need to get a reference to this function
this.hide();
}.bind(this));
this.show();
},
show: function() {
// TODO: cool web 2.0 stuff here!
},
hide: function() {
alert(this.id);
//this.removeEvent('mouseout', ?); // need reference to the function to remove
/*** this works, but what if there are unrelated mouseout events? and the class instance still exists! ***/
//this.anchor.removeEvents('mouseout');
//delete(this); // does not work !
//this = null; // invalid assignment!
//this = undefined; // invalid assignment!
}
});
What currently happens with the above code:
1st time out: alerts 1
2nd time out: alerts 1, 2
3rd time out: alerts 1, 2, 3
etc
Desired behavior:
1st time out: alerts 1
2nd time out: alerts 2
3rd time out: alerts 3
etc
The problem is, each time I mouse over the link, I'm creating a new class instance and appending a new mouseout event for that instance. The class instance also remains in memory indefinitely.
On mouseout I need to remove the mouseout event and destroy the class instance, so on subsequent mouseovers we are starting fresh.
