openstack
/
horizon
Code Issues Proposed changes

Updates contribution guidelines for JS object performance 

In a new section, titled performance, a requirement is added
for JavaScript code to limit the re-creation of objects in
the same scope. An example with jQuery is given with explanation.

Change-Id: I2f0d8392277f65384389d8d20154d645197050af
Partial-Bug: #1412971
This commit is contained in:
Matt Farina 2015-01-29 10:15:28 -05:00
parent b4091382c9
commit 52f401457f
1 changed files with 22 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
doc/source/contributing.rst
View File

@ -309,6 +309,28 @@ Required
* Avoid commented-out code.
* Avoid dead code.
**Performance**
* Avoid creating instances of the same object repeatedly within the same scope.
Instead, assign the object to a variable and re-use the existing object. For
example:
.. code ::
$(document).on('click', function() { /* do something. */ });
$(document).on('mouseover', function() { /* do something. */ });
A better approach:
.. code ::
var $document = $(document);
$document.on('click', function() { /* do something. */ });
$document.on('mouseover', function() { /* do something. */ });
In the first approach a jQuery object for ``document`` is created each time.
The second approach creates only one jQuery object and reuses it. Each object
needs to be created, uses memory, and needs to be garbage collected.
Recommended
~~~~~~~~~~~