Handling 'Zombie Children' and Component Teardown in Complex Viewport Logic

Zombie children are component instances that persist in memory after their parent has been unmounted due to uncleared global references.

This occurs most often in 'Virtual List' implementations or 'Keep-Alive' scenarios. If a child component registers a listener on a global event bus or a ResizeObserver but doesn't unregister it, the component instance cannot be garbage collected. Senior developers must implement strict 'Teardown' contracts using onUnmounted or onBeforeUnmount for all external side effects.