onDetach

Runs once, when the element leaves the modifier or the node is released/reused.

Property nodes come apart in the reverse of the order the modifier declared them last, so a node putting back what it read finds every node declared before it still standing. Subscription nodes are held by position instead, and come apart after the property diff has restored what left the modifier and applied what stands, so what one of them reads as it goes is what the pass leaves behind.