asap scheduler throws error with limiting interval via take

[kwonoj]

RxJS version:
5.3.1

Code to reproduce:

Rx.Observable.interval(100, Rx.Scheduler.asap).take(3).subscribe((x) => {
  console.log(x);
});

Expected behavior:

Actual behavior:

Additional information:

Error: executing a cancelled action
    at AsapAction.AsyncAction.execute (C:\github\test\node_modules\rxjs\scheduler\AsyncAction.js:83:20)
    at AsapScheduler.flush (C:\github\test\node_modules\rxjs\scheduler\AsapScheduler.js:22:32)
    at ontimeout (timers.js:386:14)
    at tryOnTimeout (timers.js:250:5)
    at Timer.listOnTimeout (timers.js:214:5)

[kwonoj]

Seems this was happening in 5.3.0 as well, not a regression between patches.

[trxcllnt]

@kwonoj I'll take a look

[dreamershl]

I encounter this issue too. And find it is caused by the AnimationFrameAction unmatched requestAsyncId/recycleAsyncId process.

in request, if the delay is positive value, it will call the super method, the AsynAction will just use the "setInterval". But in the recycleAsyncID triggered by the "unsubscribe", the checking "delay === null && this.delay > 0" will be false. So the corresponding "clearInterval" isn't properly called.

All are just because the "AsyncAction._unsubscribe" function set 'delay' null first before the "recycleAsyncId"

protected _unsubscribe() {

    const id = this.id;
    const scheduler = this.scheduler;
    const actions = scheduler.actions;
    const index = actions.indexOf(this);

    this.work  = null;
    this.delay = null;
    this.state = null;
    this.pending = false;
    this.scheduler = null;

    if (index !== -1) {
      actions.splice(index, 1);
    }

    if (id != null) {
      this.id = this.recycleAsyncId(scheduler, id, null);
    }
  }

       AnimationFrameAction.prototype.requestAsyncId = function (scheduler, id, delay) {
        if (delay === void 0) { delay = 0; }
        // If delay is greater than 0, request as an async action.
        if (delay !== null && delay > 0) {
            return _super.prototype.requestAsyncId.call(this, scheduler, id, delay);
        }
        // Push the action to the end of the scheduler queue.
        scheduler.actions.push(this);
        // If an animation frame has already been requested, don't request another
        // one. If an animation frame hasn't been requested yet, request one. Return
        // the current animation frame request id.
        return scheduler.scheduled || (scheduler.scheduled = AnimationFrame.requestAnimationFrame(scheduler.flush.bind(scheduler, null)));
    };
    AnimationFrameAction.prototype.recycleAsyncId = function (scheduler, id, delay) {
        if (delay === void 0) { delay = 0; }
        // If delay exists and is greater than 0, or if the delay is null (the
        // action wasn't rescheduled) but was originally scheduled as an async
        // action, then recycle as an async action.
        if ((delay !== null && delay > 0) || (delay === null && this.delay > 0)) {
            return _super.prototype.recycleAsyncId.call(this, scheduler, id, delay);
        }
        // If the scheduler queue is empty, cancel the requested animation frame and
        // set the scheduled flag to undefined so the next AnimationFrameAction will
        // request its own.
        if (scheduler.actions.length === 0) {
            AnimationFrame.cancelAnimationFrame(id);
            scheduler.scheduled = undefined;
        }
        // Return undefined so the action knows to request a new async id if it's rescheduled.
        return undefined;
    };

[trxcllnt]

@dreamershl oh thanks, great catch! will have the fix PR'd soon

[trxcllnt]

@dreamershl @kwonoj PR in #2638

[venikx]

@trxcllnt Thanks!
I noticed this issue too but didn't know if it was my lack of Scheduler knowledge or not. I'll upgrade ASAP when it gets merged!

[lock]

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