useOptimisticAction

const action = useOptimisticAction(typedReference, {
  currentData,
  updateFn, // your immutable (input, current) => newValue function
  ...actionOptions,
})

It returns the useAction members plus readonly optimisticData. execute/executeAsync apply the optimistic update before the request. Only one optimistic operation is owned; newer execution replaces older pending work.

Failure, cancellation, or reset restores the baseline only while the ref still contains the installed optimistic value. External ref replacement is preserved. In-place mutations cannot be detected by the identity guard.

Success retains optimistic state until your application merges or refreshes authoritative output. TOutput is never assumed to equal TData. cancel/reset release owned optimism; server-side mutations already underway can still complete. Example and reconciliation guidance.

If updateFn throws, no request starts; executeAsync rejects and execute logs the failure. Keep updateFn pure and immutable.