[wp-trac] [WordPress Trac] #15650: Inefficient selectors in common.dev.js

[WordPress Trac]

#15650: Inefficient selectors in common.dev.js
-------------------------+--------------------------------------------------
 Reporter:  GamajoTech   |       Owner:                
     Type:  enhancement  |      Status:  new           
 Priority:  normal       |   Milestone:  Future Release
Component:  Performance  |     Version:                
 Severity:  minor        |    Keywords:  needs-refresh 
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Comment(by GamajoTech):

 Replying to [comment:2 azaozz]:
 > These two do the same thing:
 > {{{
 > $('.wp-menu-toggle', menu)...
 > }}}
 >
 > {{{
 > menu.find('.wp-menu-toggle')...
 > }}}
 >
 > They limit the search for the `.wp-menu-toggle` class only to children
 of `menu`.

 Agreed.


 >Did some testing few months ago and the first one was slightly faster.
 As the first is converted internally to use the second, I find your
 results interesting. Could you share your test code?

 From http://api.jquery.com/jQuery/

   Internally, selector context is implemented with the .find() method, so
 $('span', this) is equivalent to $(this).find('span').

 I see no reason not to jump straight to using the find() method for the
 optimizations I've listed.

 > It can also be written as:
 > {{{
 > $('li.wp-has-submenu', '#adminmenu')...
 > }}}
 > i.e. find `li` nodes that have `wp-has-submenu` class but search only in
 the node with id = `adminmenu`.

 Actually, no it can't. Again from http://api.jquery.com/jQuery/ the
 context is:

   A DOM Element, Document, or jQuery to use as context

 A string doesn't cut it; the context would still be "document", and not
 "#adminmenu".

 Further information at http://brandonaaron.net/blog/2009/06/24
 /understanding-the-context-in-jquery

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Ticket URL: <http://core.trac.wordpress.org/ticket/15650#comment:5>
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