The largest issue I have with Rrule is that it has no real timezone support. Dates are always generated based off the timezone of your machine/server. I want the same functionality but with the ability to specify what timezone the resulting dates should be in.
I also wanted to see if it was possible to make a much more lightweight library. For the most part moment-timezone
already handles the complex logic of adding months, weeks, days to a date, so why not leverage that for date logic?