_getElementRect returns an new object

[gregmax17]

I was doing some digging around the code and noticed the _getElementRect method returns a new object. For this particular method/instance, it runs this method EVERY frame the mouse/touch moves. This is poor practice, see the test here.

Creating some kind of static object like _lastElementRect with the properties top, left, right, and bottom and reseting those values every time the _getElementRect is called instead of the newly created object will help performance a lot.

[hilts-vaughan]

Wouldn't that make it a reference type suddenly and be a breaking change?
On May 7, 2015 5:23 PM, "Gregory Athons" notifications@github.com wrote:

I was doing some digging around the code and noticed the _getElementRect
method returns a new object. For this particular method/instance, it runs
this method EVERY frame the mouse/touch moves. This is poor practice, see
the test here http://jsperf.com/object-set/2.

Creating some kind of static object like _lastElementRect with the
properties top, left, right, and bottom and reseting those values every
time the _getElementRect is called instead of the newly created object will
help performance a lot.

—
Reply to this email directly or view it on GitHub
#611.

[kyfoote]

At quick glance, I don't see how this change would break anything currently. _getElementRect only gets called from the stage._updatePointerPosition function and only keeps that object for that function closure. But if _getElementRect is meant to be used on other elements in other situations, then returning a new object makes sense. However seems like it would be nice to prevent object creation in a place like _updatePointerPosition.

[MannyC]

Well, it's marked a protected rather than private so in theory somebody could have obeyed the documentation, extended Stage and made use of it directly, although I doubt that's common and the proposed change would only break it if the caller is trying to hang on to and reuse the returned object. Another option is to have an optional second parameter, and have _getElementRect use the provided object if it's supplied. This would leave the maintenance of the object up to the calling function.

[lannymcnie]

We can consider this for the next version. It could be a valuable optimization.