/**
 * Races an operation against an abort signal.
 *
 * @param operation - The promise to await
 * @param signal - The signal that can abort the operation
 * @returns The operation's fulfilled value, or rejects with an `AbortError` if the signal aborts first
 */
export function awaitWithAbort<T>(operation: Promise<T>, signal: AbortSignal): Promise<T> {
  return new Promise((resolve, reject) => {
    let settled = false;
    const finish = (callback: () => void): void => {
      if (settled) return;
      settled = true;
      signal.removeEventListener("abort", abort);
      callback();
    };
    const abort = (): void => {
      const error = new Error("Operation aborted.");
      error.name = "AbortError";
      finish(() => reject(error));
    };

    operation.then(
      (value) => finish(() => resolve(value)),
      (error) => finish(() => reject(error)),
    );
    if (signal.aborted) abort();
    else signal.addEventListener("abort", abort, { once: true });
  });
}