Consider using rSchedule instead of rrule

[jorroll]

Even though we only need to look forward, rrule.js has to iterate all the way from the start date (dtstart) every time in order to calculate the next occurrence.

Feel free to ignore this issue, but I maintain rSchedule and invite you to consider using rSchedule (Github (mirror) or Gitlab (original)) as a base instead of rrule.

Unlike rrule, rSchedule begins iterating a rule from the provided start time and does NOT need to calculate all occurrences from the beginning of the rule (though it does need to calculate all occurrences if a rule has a COUNT property).

This being said, rSchedule does not provide support for the BYWEEKNO, BYYEARDAY, or BYSETPOS iCal rules while rrule does. For a tool primarily intended to handle any kind of iCal rule, sticking with rrulejs could be the correct choice.