useLockFn
Overview
useLockFn wraps an action with a small concurrency lock. While one invocation is pending, later calls resolve to undefined.
Signature
function useLockFn<Args extends readonly unknown[], Result>(
fn: (...args: Args) => Result | PromiseLike<Result>,
options?: UseLockFnOptions,
): LockFn<Args, Awaited<Result>>;Parameters
fn may return a value or a promise. options.onError observes a failure before the original rejection is rethrown.
Returns
A stable function returning Promise<Result | undefined>. A call made while the lock is held resolves to undefined.
Behavior
The lock is acquired before invoking fn and released in finally, including when fn throws or rejects. Errors are never swallowed; onError is only an observation hook.
SSR / RSC
The wrapper is safe to create during SSR and does not invoke fn during render. Invoke it from a Client Component event or action.
Example
Composition
Use it for submit, save, or mutation actions where duplicate requests must be prevented without disabling the surrounding UI.