DTSTART/DTEND with incorrect DATE-TIME should fail hard on parse instead of serializing to `T::`

[a-schild]

ical.js in version 1.5.0 On windows 11 and debian with nodejs version 16

Importing this ical file works fine:

BEGIN:VCALENDAR
PRODID:-//eluceo/ical//2.0/EN
VERSION:2.0
CALSCALE:GREGORIAN
X-PUBLISHED-TTL:PT1H
X-WR-CALNAME:Calname
BEGIN:VEVENT
UID:[email protected]
DTSTAMP:20230912T115144Z
LAST-MODIFIED:20230523T064918Z
SUMMARY:Kinderwoche
DESCRIPTION:
DTSTART:20231008
DTEND:20231013
LOCATION:Mylocation
ORGANIZER:mailto:[email protected]
SEQUENCE:1
X-MICROSOFT-CDO-ALLDAYEVENT:TRUE
END:VEVENT
END:VCALENDAR

But when I export it back out, the all day events with no time have an invalid time part in the ics file/content The DTSTART and DTEND fierlds/values have a completely different format, with - delimiters and T:: at the end.

BEGIN:VCALENDAR
PRODID:-//iCal.js churchtool calendar merger
VERSION:2.0
CALSCALE:GREGORIAN
BEGIN:VEVENT
UID:[email protected]
DTSTAMP:20230912T100054Z
LAST-MODIFIED:20230523T064918Z
SUMMARY:Kinderwoche
DESCRIPTION:
DTSTART:2023-10-08T::
DTEND:2023-10-13T::
LOCATION:Mylocation
ORGANIZER:mailto:[email protected]
SEQUENCE:1
X-MICROSOFT-CDO-ALLDAYEVENT:TRUE
END:VEVENT
END:VCALENDAR

ee use the toString() method to produce the ical file/content

        let comp = new ICAL.Component(['vcalendar', [], []]);
        comp.updatePropertyWithValue('prodid', '-//iCal.js churchtool calendar merger');
        comp.updatePropertyWithValue('version', '2.0');
        comp.updatePropertyWithValue('calscale', 'GREGORIAN');
        for (const srcEvent of newCalendarContent[key]) {
            // Add the components from imported ical
            comp.addSubcomponent(srcEvent);
        }
        logger.info("Output to: "+singleConfig.output.fileName);
        fs.writeFile(singleConfig.output.fileName, comp.toString(), err => {
            if (err) {
                console.error(err);
            }
            // file written successfully
        });  

[kewisch]

The default type for DTSTART and DTEND is DATE-TIME, so it should be:

DTSTART;VALUE=DATE:20231008
DTEND;VALUE=DATE:20231013

Granted, it should fail hard in strict mode, and be lenient in strict mode. I believe there was some code added there, but I didn't double check. Let's leave this as an enhancement to fail correctly without using T::.

[kewisch]

https://github.com/kewisch/ical.js/issues/515 is what I had in mind, PR was abandoned.