On Mon, Jul 20, 2009 at 10:30 PM, David Flanagan <[email protected]>wrote:
>
> What about the performance implications of creating those jQuery objects
> for each call? Could you check the length property of the callback
> function and only pass the jQuery object if it is actually declared to
> expect 2 arguments?
Yep! John and I had discussed this. I think it's the way to go.
>
>
> What about modifying each() so that it passes three arguments to its
> callback: the index, the element, and the wrapped element:
>
> function(i, e, $e) { // e === $e[0] }
>
> That avoids the compatibility problem, but loses the parallel with the
> other methods, unless you pass both e and $e to their callback as well.
Nah. If we do it, we need to do it right. I'd be ok with a jQuery.legacyEach
= true, but John didn't like that ;)
>
>
> David
>
> John Resig wrote:
> > A quick example:
> >
> > $(".msg").each(function(i, $this){
> > $(".hide", this).click(function(){
> > $this.hide();
> > });
> > });
> >
> > I actually proposed this set of changes to Yehuda on IM and then had a
> > back and forth as to how to best implement them. I think they actually
> > hold some promise. I like this since it's relatively pain-free which
> > helping to reduce extra syntax (when dealing with closures in jQuery
> > it's common that you'll need to declare references to the wrapped jQuery
> > set - something that this avoids).
> >
> > The proposal is a set of 3 changes - each change is making the second
> > argument of a callback function equal to $(this).
> >
> > - Modifying existing callbacks that have no second argument (like
> > .filter, as Yehuda mentioned).
> > - Modifying event callbacks to have a second argument be $(this)
> > (which, can conflict with .trigger(event, data)).
> > - Modifying each callbacks to have a second argument be $(this)
> > (replacing the existing second argument of this).
> >
> > Obviously changing the second incoming argument to
> > .each(function(i,$this)) is going to require a little bit of finesse. I
> > did a quick search on Google Codesearch but didn't see any immediate
> > warning signs:
> > http://www.google.com/codesearch?hl=en&lr=&q=
> > <http://www.google.com/codesearch?hl=en&lr=&q=
> >\.each\%28\s*function\%28\s*\w%2B%2C\s*\w%2B\s*\%29+lang%3Ajavascript&sbtn=Search
> >
> > If we make a change like this I would like it to be an all-or-nothing
> > proposition (having a half-baked API modification landing seems kind of
> > lame) BUT it must be done in a way that we're sure won't break important
> > code. (At the very least, a change like this would have to be done in a
> > major 1.x release.)
> >
> > A quick note: It's probably important to use function(i, $this) in the
> > examples (to help differentiate it from a "normal" self [which generally
> > equates to var self = this;]).
> >
> > --John
> >
> >
> > On Mon, Jul 20, 2009 at 11:14 PM, Yehuda Katz <[email protected]
> > <mailto:[email protected]>> wrote:
> >
> > At the moment, traversal callbacks, like the ones passed to
> > find/filter/etc. take a single "index" parameter. I'd like to
> > propose that they are unified with .each as follows:
> >
> > $("div").filter(function(i, self) {
> > // stuff
> > });
> >
> > As a separate concern, I'd like to discuss changing the second
> > parameter in both to be a jQuery object. Obviously, it would need to
> > be done via slow deprecation for .each, but I don't think it'd break
> > all that much code:
> >
> > $("div").filter(function(i, self) {
> > // self == $(this)
> > })
> >
> > Thoughts?
> >
> > --
> > Yehuda Katz
> > Developer | Engine Yard
> > (ph) 718.877.1325
> >
> >
> >
> >
> > >
>
>
> >
>
--
Yehuda Katz
Developer | Engine Yard
(ph) 718.877.1325
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