ICAL expression RRULE not working correctly

[TDSParticipant]

Hello,

I think the iCal parser or the calculation for the views is broken.

iCal example:

BEGIN:VCALENDAR
PRODID:-//Mozilla.org/NONSGML Mozilla Calendar V1.1//EN
VERSION:2.0
BEGIN:VTIMEZONE
TZID:Europe/Berlin
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:19700329T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:19701025T030000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
CREATED:20190404T180240Z
LAST-MODIFIED:20190404T180307Z
DTSTAMP:20190404T180307Z
UID:06923ad6-952a-4028-b4d7-6530f8e0bef3
SUMMARY:Rangliste Offen / Gilde 2000
RRULE:FREQ=MONTHLY;BYDAY=-1FR
DTSTART;TZID=Europe/Berlin:20190410T193000
DTEND;TZID=Europe/Berlin:20190410T235900
TRANSP:OPAQUE
LOCATION:Gilde 2000
END:VEVENT
END:VCALENDAR

Expected: Every last friday in month at 19:30 (7:30 pm).
Result (incorrect):

iCal library:

var comp = new ICAL.Component(calData);
var eventComps = comp.getAllSubcomponents("vevent");
// console.log(JSON.stringify(eventComps));
// map them to FullCalendar events
eventComps.forEach(function(vevent) {
	var counter = 0;
	const iCalEvent = new ICAL.Event(vevent);
		if (!vevent.hasProperty('dtstart')) {
		return;
	}
	// ...

	if (iCalEvent.isRecurring()) {
		// ...
		var next;
		var expand = new ICAL.RecurExpansion({
			component: vevent,
			dtstart: vevent.getFirstPropertyValue('dtstart')
		});
		while ((next = expand.next())) {
			if (counter++ > 3) break;
			console.log(next._time); // correct
			// ...
			// push event into some array
		}
	} else {
		// ...
		// push event into some array
	}
});

Result of Mozilla iCal library (ical.min.js, correct):
{year: 2019, month: 4, day: 26, hour: 19, minute: 30, …}
{year: 2019, month: 5, day: 31, hour: 19, minute: 30, …}
{year: 2019, month: 6, day: 28, hour: 19, minute: 30, …}
{year: 2019, month: 7, day: 26, hour: 19, minute: 30, …}

[HristoParticipant]

Hello TDS,

The data that you provided is not fully compatible.
For example, the date you set is “Unparseable date” if you try to check it with some of the online ‘ICAL’ validators.
Could you provide us with a working example in jsfiddle/jseditor?
You could use this one as a base.

Best Regards,
Hristo Hristov

jQWidgets team
https://www.jqwidgets.com

[TDSParticipant]

Sorry for late replay, but I’ve had holidays
The data is from Lightning export of Mozilla Thunderbird. And the ICAL library is also from Mozilla. They try to cover all ICS date in the wild. So it should be correct considering RFC 2445 and 5445.

[HristoParticipant]

Hello TDS,

There have different standards.
We tested and it seems to work fine with “Microsoft Outlook” and “Google Calendar”.
I would like to suggest you could export from them and import to our jqxScheduler.
Or if you want also could do it in the opposite direction.

Best Regards,
Hristo Hristov

jQWidgets team
https://www.jqwidgets.com

[Author]

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