LifecycleClient Component
useUnmountedRef
Overview
useUnmountedRef provides a stable boolean ref for guarding delayed work that may finish after a component has been removed.
Signature
ts
function useUnmountedRef(): RefObject<boolean>;Parameters
This Hook takes no parameters.
Returns
A stable ref whose current value is false while the component is live and true during unmount cleanup.
Behavior
The ref remains stable across renders. Cleanup sets it to true; Strict Mode's development replay restores false during the next setup so a live component is not marked as unmounted.
SSR / RSC
The initial value is false during SSR and no browser API is accessed. Read the ref from Client Component effects or callbacks.
Example
Composition
Use it as a guard around optional state updates from timers, subscriptions, or promise continuations when explicit cancellation is not available.