Async Set Interval

[pacoccino]

This is not a bug, but a feature request.
I already implemented that feature on my own, but I think would be great to have it in async module.

The native setInterval is not well-suited for async methods and error handling.

I propose a new setIntervalAsync method that would handle async functions, correctly run and stop intervals and correctly handle errors.
Prototype: setInvervalAsync(asyncFunction, delay, onError). Returns clear function.

Behaviour:

• Wait that asyncFunction finishes to run the interval.
  If function takes 100ms to finishes and delay is 50ms:
  0 ms: start fn
  100ms: end fn, start interval
  150ms: start fn again
  250ms: end fn

• If asyncFunction throws, call onError callback with the error. Continues the interval and run again asyncFunction after interval.

• When clear function is called, returns a Promise that is resolved when current fn execution is finished. Do not run again interval.

I'll create a package for my implementation soon and share it here.

[aearly]

Let us know when you have an example package, we could link it in the readme.