Interval: Immediately emit 0?

Before it’s too late, I’d like to discuss the following question: When should Observable.interval(t) emit its first element (which is 0): a) right after the observer subscribed, or b) only after a delay of t?

Currently, we have b), but I’d vote for a), because I’ve seen many people stumble over this. I think it makes more sense if after n*t time, it emits n. Or a third possiblilty: c) start with 1, and emit it after a delay of t

[benjchristensen]

Sitting here with @headinthebox to get this answered …

The interval operator will always have a delay before emitting, so it behaves correctly.

If an immediate values is wanted then use timer or startsWith(0).interval() if you don’t care about the values produced by interval.

The reason for interval and timer is that interval is a convenience overload for `timer.

The timer that would perform this is:

public static Observable<Long> timer(long initialDelay, long period, TimeUnit unit)

It would used as:

Observable.timer(0, 100, TimeUnit.MILLISECONDS)

That would immediately emit 0 and then increment 1, 2, 3, … n every 100 milliseconds.

[FireZenk]

Observable.timer(0, 100, TimeUnit.MILLISECONDS)

is deprecated but now you can use

Observable.interval(0, 100, TimeUnit.MILLISECONDS)