RxJs V2.0.20327 Beta Bug - startWith(undefined) throws exception

Question

startWith() crashes if first argument is undefined:

    QUnit.test("RxJs 2.0 Beta Bug: startWith() does not crash if first argument is undefined", 1, function () {
        Rx.Observable.empty().startWith(undefined, 1);
        QUnit.ok(true, "no error");
    });

Crashes with this error:Cannot read property 'now' of undefined - {} (+9ms)

Also...the function seems to accept an optional Scheduler first argument.  Could the vsdoc be updated to mention that?

Thanks!

Answer 1

Yes, I'll update the documentation.  It's getting confused because it thinks the undefined is the scheduler.  Is it your intention to pass in undefined as an actual value to this function?

Matt

Answer 2

Yes, the code was more complicated than the above, but basically undefined was one of the values I was passing through the observable.  I fixed my copy by just changing the "arguments[0]!==null" to "arguments[0]!=null" inside startWith().  But it occurs to me that it will still cause problems if my value actually has a "now" member (Dates for example).  Seems like the only safe way is to use instanceOf Rx.Scheduler, which may or may not be possible depending on how you created the various schedulers.

I suppose it is not the end of the world to keep the simple duck typing mechanism you have now--now that I know I can supply a scheduler as the first argument, I can avoid the problem by always supplying a scheduler.

Thanks!