JS: capture a static snapshot of an object at a point in time with a method
- by Barney
I have a JS object I use to store DOM info for easy reference in an elaborate GUI.
It starts like this:
var dom = {
m:{
old:{},
page:{x:0,y:0},
view:{x:0,y:0},
update:function(){
this.old = this;
this.page.x = $(window).width();
this.page.y = $(window).height();
this.view.x = $(document).width();
this.view.y = window.innerHeight || $(window).height();
}
I call the function on window resize:
$(window).resize(function(){dom.m.update()});
The problem is with dom.m.old. I would have thought that by calling it in the dom.m.update() method before the new values for the other properties are assigned, at any point in time dom.m.old would contain a snapshot of the dom.m object as of the last update – but instead, it's always identical to dom.m. I've just got a pointless recursion method.
Why isn't this working? How can I get a static snapshot of the object that won't update without being specifically told to?
Comments explaining how I shouldn't even want to be doing anything remotely like this in the first place are very welcome :)
