Function testingEffect

packages/core/test/signals/effect_util.ts:16–28

(
  effectFn: (onCleanup: (cleanupFn: WatchCleanupFn) => void) => void,
)

 * A wrapper around `Watch` that emulates the `effect` API and allows for more streamlined testing.
 */
export function testingEffect(
  effectFn: (onCleanup: (cleanupFn: WatchCleanupFn) => void) => void,
): () => void {
  const w = createWatch(effectFn, queue.add.bind(queue), true);

  // Effects start dirty.
  w.notify();

  return () => {
    queue.delete(w);
    w.destroy();
  };
}

export function flushEffects(): void {
  for (const watch of queue) {