Rate limit and throttle: Last item throttled about async-sema

[OlliV]

I believe that's correct behavior, at least it's something that we wanted for the applications where we use the rate limiter, that are usually very long running tasks.

For downloading/uploading files I would recommend to use the semaphore primitive directly because what you usually want to do is to download/upload n files concurrently all the time, without pauses or gaps.

const s = new Sema(2);
await Promise.all(
  images.map(async (image, index) => {
    await s.acquire();
    const parsed = await _prepImage.call(this, image);
    await util.downloadImage(parsed.url, parsed.target);
    s.release();
  })
);

or more correctly if you want to keep s global and never leak the tokens, then you should use

try {
  await s.acquire();
  ...
} catch (err)
  ...
} finally {
  s.release();
}

[mhulse]

Awesome! Thank you so much @OlliV, that should do the trick for me.

I really appreciate your help!