/** Serialize refreshes, retaining one follow-up if a change arrives mid-request. */
export function realtimeRefresh(
  refresh: () => Promise<void>,
  onError: (error: unknown) => void,
) {
  let running = false;
  let pending = false;
  let closed = false;
  async function request() {
    if (closed) return;
    pending = true;
    if (running) return;
    running = true;
    try {
      while (pending && !closed) {
        pending = false;
        try {
          await refresh();
        } catch (error) {
          if (!closed) onError(error);
        }
      }
    } finally {
      running = false;
    }
  }
  return {
    request,
    close: () => {
      closed = true;
      pending = false;
    },
  };
}