Function isWatchResourceExhaustion

src/sync/watcher.ts:101–108

* True when an error is OS watch/file-descriptor exhaustion (EMFILE/ENFILE). * Prefers the structured `err.code`; falls back to message matching ONLY when * no code is present (some platforms surface a bare Error from `fs.watch`).

(err: unknown)

 * no code is present (some platforms surface a bare Error from `fs.watch`).
 */
function isWatchResourceExhaustion(err: unknown): boolean {
  const e = err as NodeJS.ErrnoException | undefined;
  if (e?.code === 'EMFILE' || e?.code === 'ENFILE') return true;
  if (!e?.code && e?.message) {
    return /EMFILE|ENFILE|too many open files/i.test(e.message);
  }
  return false;
}

/**
 * True when an error is Linux inotify *watch-count* exhaustion. `fs.watch`