The documentation for the signal option of the add() method is misleading:

AbortSignal for cancellation of the operation. When aborted, it will be removed from the queue and the queue.add() call will reject...

However, when a providing an abort signal, the associated items are not removed from the queue. This is problematic when combined with an intervalCap:

const queue = new PQueue({
  concurrency: 1,
  interval: 1000,
  intervalCap: 1,
});

const controller = new AbortController();

for (let i = 0; i < 10; i++) {
  queue.add(() => console.log('foo'), { signal: controller.signal });
}
queue.add(() => console.log('Hello World'));

controller.abort();

In such a scenario I would expect to get "Hello World" logged immediately (or perhaps after 1 second) but instead all 10 of the cancelled tasks remain in the queue and are ejected one by one, causing "Hello World" to print after 10 seconds.