QuestQueue

A concurrency-limited async task queue. At most simultaneous tasks run at once; the rest wait, and a slot is refilled as each one finishes. Use it for batch uploads or batch requests: anything you cannot fire all at once.

API

new QuestQueue({ simultaneous })

Example

import { QuestQueue } from 'ranuts';

const queue = new QuestQueue({ simultaneous: 3 });
const results = await Promise.all(urls.map((url) => queue.add(() => fetch(url))));

// Or fire and forget, then wait for everything including failures
urls.forEach((url) => queue.add(() => fetch(url)).catch(report));
await queue.onIdle();

Notes

1. FIFO: tasks run in the order they were added.
2. One failure does not stall the queue. Each task rejects its own promise; the next task starts regardless.
3. A task that throws synchronously is caught too, so it cannot leak out of add() and leave the concurrency counter stuck.
4. allSettled keeps input order and reports each outcome separately.