Respect timezone of Luxon DateTime instance when rendering an allday event

[cimnine]

I store dates as ISO timestamps, like 2024-03-17T00:00:00.000+01:00. When I add an all day event to a calendar like in the following example, it is rendered as 20240316 in the ical format, but 20240317 would be my expectation.

const cal = new ICalCalendar();
const luxonStartDate = DateTime.fromISO('2024-03-17T00:00:00.000+01:00', { setZone: true });
const luxonEndDate = DateTime.fromISO('2024-03-18T00:00:00.000+01:00', { setZone: true });
const event = new ICalEvent({
  allDay: true,
  start: luxonStartDate,
  end: luxonEndDate,
}, cal);

const actual = event.toString();
// actual:
// DTSTART;VALUE=DATE:20240316
// DTEND;VALUE=DATE:20240317

// expected:
// DTSTART;VALUE=DATE:20240317
// DTEND;VALUE=DATE:20240318

This does not happen, when the cal object is given a fixed timezone, like cal.timezone('Europe/Zurich'). But that only works if all DateTime instances are in that same timezone – which they might not be in my case. Therefore, my instances of ICalCalendar don't have a timezone set, yet still I expect that the timezone which is embedded in the DateTime instance is respected.

I've created a PR with just some test (for now) to further explain my situation as unit tests: #591
In order to fix it, I'm unsure whether it needs to be addressed in event.ts#toString() or in tools.js#formatDate().

[sebbo2002]

Ah cool, I didn't know you could save the time zone in a DateTime object. I actually only work with UTC, maybe that's why. This is not supported yet, I always assumed that the objects were already adjusted to the local time when I get them in ical-generator. Thank you.

[sebbo2002]

🎉 This issue has been resolved in version 7.1.0-develop.1 🎉

The release is available on:

• npm package (@next dist-tag)
• GitHub release
• v7.1.0-develop.1

Your semantic-release bot 📦🚀

[sebbo2002]

🎉 This issue has been resolved in version 7.1.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release
• v7.1.0

Your semantic-release bot 📦🚀