RxJS 5 bufferWithTimeOrCount? (add maxCount to bufferTime)

[avielfedida]

So RxJS 5 currently not containing bufferWithTimeOrCount, is it planned to be added in the future?, anyway I was looking for comparable way to "do" bufferWithTimeOrCount in RxJS 5, should I create my own operator or there is a nicer combo with the already ported operators?

[benlesh]

Hmmm... seems like an oversight. I think we can probably add an additional argument to bufferTime to cover this without impacting performance greatly.

Until we add that, you could use something like this:

(I haven't tested it, and it looks a little gross but with some tweaks it may work):

function bufferWithTimeOrCount(source, duration, bufferSize) {
  let reset = false;

  const buffers = source.scan((buffer, x) => {
    if (reset) {
      buffer = [];
      reset = false;
    }
    buffer.push(x);
    return buffer;
  }, []).share();

  const bufferCounted = buffers.filter(buffer => buffer.length < bufferSize);
  const timer = Observable.of(null).merge(bufferCounted).switchMap(() => Observable.timer(duration));

  return buffers.sample(timer.merge(bufferCounted)).do(() => reset = true);
}

[benlesh]

Thank you for your patience and for bring this issue up for us, @avielfedida. We'll get it fixed.

[benlesh]

Contributors or those looking to implement this:

The idea I have here is that we can add an optional maxBufferSize parameter to bufferTime (likewise with windowTime) that would default to Number.POSITIVE_INFINITY. Then rework the the operator to support that functionality.

The operator function itself can be mildly polymorphic: bufferTime(1000), bufferTime(1000, scheduler), or bufferTime(1000, 5, scheduler), but per Rx design, scheduler should be the last argument.

[justinwoo]

Sorry if I have the details wrong, but bufferTimeOrCount only allows a single buffer at a time, right? And as soon as a buffer is flushed, a new buffer starts immediately? (e.g. this JSBin for single/double clicks)

It looks like in the current implementation of bufferWithTime, you'd have to purposefully limit and rewire the scheduling of opening multiple buffers and all, which sounds hard/like a lot of work.

I have a small implementation for bufferTimeOrCount with this base spec, but I don't know if this necessarily behaves as expected.

[lock]

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