[Feature]: Tree Animation or Allow passing tree node items into TreeVirtualizer？

[frankchen211]

Describe the feature

I’m trying to implement tree expand & collapse animations following the Ant Design Vue's tree method:

NodeList.tsx
MotionTreeNode.tsx
Based on this approach, the tree node items are dynamically computed and passed to the Virtualizer component.

If there’s an easier way to animate tree items, I would appreciate any advice!

I’ve attempted using TransitionGroup, but the result doesn’t match the animation style of Ant Design Tree.

Another question is how to get and watch the changes of flattenItems in TreeRoot?

Additional information

• I intend to submit a PR for this feature.
• I have already implemented and/or tested this feature.