ScrollPanel: Errors in moveBar() when xBar and yBar attributes don't exist

[autoboxer]

Describe the bug

In some cases, the requestAnimationFrame() that sets attributes for this.$refs.xBar and this.$refs.yBarthrow errors due to neitherxBarnoryBarexisting onthis.$refs`.

screenshot

Reproducer

none - PR incoming though

PrimeVue version

3.50.0

Vue version

3.x

Language

ES6

Build / Runtime

Vite

Browser(s)

Chrome 123.0.6312.87

Steps to reproduce the behavior

This doesn't seem to happen in all cases and is hard to reproduce, but in my case it's due to a scrollbar which doesn't need to be rendered, being placed in a Panel which takes up 1/3 of the screen width. When it does occur, it happens on load, before the ScrollPanel is interacted with in any way.

Expected behavior

No errors are thrown due to the ScrollPanel component loading.

[tugcekucukoglu]

How can we replicate this issue? Could you share a stackblitz link?

[autoboxer]

although it's happening consistently in my app, I haven't been able to easily replicate the issue. I'll hopefully free up a bit next week and can try to put something together, but may not be able to showcase the same behavior in a sandbox environment. I was hoping the error showing that there are cases where xBar and yBar are not set as expected when the requestAnimationFrame is run would be adequate, but I completely understand if it's not.