Should clearQueue() reject the pending promises?

[jedwards1211]

Right now it leaves them hanging indefinitely. It seems like undesirable behavior, though I guess it ultimately depends on the use case.

[sindresorhus]

There's no way to reject promises from the outside. We could maybe support cancelling them if they are of the type p-cancelable.

[jedwards1211]

There's no way to reject promises from the outside

I take it you mean promises returned by the user-supplied function, but I'm not talking about those, I'm talking about the promises p-limit created for queued functions that haven't even been called yet:

const generator = (fn, ...args) => new Promise(resolve => enqueue(fn, resolve, ...args));
                                       ^^^^^^^

We could change this to

const generator = (fn, ...args) => new Promise((resolve, reject) => enqueue(fn, resolve, reject, ...args));

And refactor the queue entries to include reject (instead of just being the bound function), so that clearQueue() can call reject on all the queue entries.

[RichardBronosky]

Could you please add an example of how to clearQueue() on error? I cannot figure it out. No matter when/where I try to call limit.clearQueue() I get TypeError: limit.clearQueue is not a function

[jedwards1211]

@RichardBronosky maybe you have an old version installed? Looks like clearQueue was only added 3 months ago.

[sindresorhus]

I think it would be better to support AbortController and let the user decide what to do about the signal.

[nickluger]

Reading the docs, I assumed this:

try {
   await Promise.all(things.map(async (thing) => limit(async () => {/*...*/}) ));
} catch (error) {
  limit.clearQueue();
  throw error;
}

would prevent promises not yet queued from running.

For example, if things.length === 1000 and limit is 3 and one of the first 3 promises throws, the queue is emptied and the remaining 997 other things and their Promises are not executed.

Is this correct?