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#6547 closed enhancement (invalid)

Opened May 07, 2010 05:05PM UTC

Closed January 14, 2011 07:55AM UTC

jQuery.each has unnecessary property lookups which are a hindrance to performance

Reported by: fitzgen Owned by: fitzgen
Priority: low Milestone: 1.5
Component: core Version: 1.4.2
Keywords: speed each Cc:
Blocked by: Blocking:

Hello jQuery!

I improved the performance of $.each while iterating over objects by storing object[ name ] in a local variable in the loop.

I ran the following to show myself that it was in fact faster with the local variable:

    <script type="text/javascript" src="jq-before.js" ></script>
    <script type="text/javascript">
      var time = (new Date).valueOf();
      var obj = {
        foo: 1,
        bar: 2,
        baz: 3,
        bang: 4,
        quux: 5
      var i = 200000;
      while (i--) {
        $.each(obj, function () {});
      alert((new Date).valueOf() - time);

FF 3.5 before: 4621 ms

FF 3.5 after: 4186 ms

Chromium 5.0.391.0 before: 331 ms

Chromium 5.0.391.0 after: 307 ms

The relevant commit is this one:

Thanks! jQuery is awesome!


Attachments (0)
Change History (5)

Changed June 15, 2010 01:44AM UTC by dmethvin comment:1

component: unfiledcore

Changed November 03, 2010 08:51PM UTC by SlexAxton comment:2

keywords: → speed each
priority: → low
status: newopen

A pull request is the fastest way to get this kind of stuff in core, but I'll push this through to the enhancement list.

Changed November 03, 2010 08:53PM UTC by SlexAxton comment:3

Also, performance related enhancements are better accepted when they come along with a example. Thanks!

Changed December 30, 2010 03:01PM UTC by dmethvin comment:4

owner: → fitzgen
status: openpending

gf3 posted his own results showing this was slower. Can you provide a example so we can test it across all browsers? Thanks.

Changed January 14, 2011 07:55AM UTC by trac-o-bot comment:5

resolution: → invalid
status: pendingclosed

Because we get so many tickets, we often need to return them to the initial reporter for more information. If that person does not reply within 14 days, the ticket will automatically be closed, and that has happened in this case. If you still are interested in pursuing this issue, feel free to add a comment with the requested information and we will be happy to reopen the ticket if it is still valid. Thanks!