Function abortableNext

lib/internal/streams/iter/pull.js:703–721

* Read one item from an async iterator, rejecting early if the signal aborts. * @param {AsyncIterator} iterator - The iterator to read from. * @param {AbortSignal|undefined} signal - Optional abort signal. * @returns {Promise >|IteratorResult }

(iterator, signal)

 * @returns {Promise<IteratorResult<Uint8Array[]>>|IteratorResult<Uint8Array[]>}
 */
function abortableNext(iterator, signal) {
  if (signal === undefined) {
    return iterator.next();
  }

  signal.throwIfAborted();

  const next = iterator.next();
  const { promise, reject } = PromiseWithResolvers();
  const onAbort = getOnAbort(reject, signal);
  signal.addEventListener('abort', onAbort, { __proto__: null, once: true });
  if (signal.aborted) {
    onAbort();
  }

  return SafePromisePrototypeFinally(SafePromiseRace([next, promise]), () => {
    signal.removeEventListener('abort', onAbort);
  });
}

/**
 * Wrap an async source so each pending read is abort-aware.