[Bug] sliceMultiDayEvents: sliced sub-events after the first start at 23:59 instead of next-day 00:00

[ago1776]

Platform

• MagicMirror² v2.37.0
• default calendar module, sliceMultiDayEvents: true

Bug

With sliceMultiDayEvents: true, a multi-day event is split into per-day slices (1/n), (2/n), … Every slice after the first is displayed as starting at 23:59 instead of the following day's 00:00.

Cause

modules/default/calendar/calendar.js, in the slicing loop (around L513–535):

let midnight = eventStartDateMoment.clone().startOf("day").add(1, "day").endOf("day");
...
event.startDate = midnight.format("x");   // start of the NEXT slice
...
midnight = midnight.clone().add(1, "day").endOf("day");

midnight is .endOf("day") (= 23:59:59.999), but it is assigned as the following slice's startDate. So each subsequent slice starts at 23:59:59.999 of the previous day instead of 00:00 of its own day, which is what gets rendered as "… 23:59".

Fix

Use the start of the day for the next slice's start:

- event.startDate = midnight.format("x");
+ event.startDate = midnight.clone().startOf("day").format("x");

Reproduce

Any all-day or timed event spanning ≥2 midnights with sliceMultiDayEvents: true; slices 2..n show "… 23:59".

[KristjanESPERANTO]

Looks like a real bug to me. And the suggested solution looks good, too 👍

Would you like to create a PR? Maybe even with a regression test.

[ago1776]

Thanks for the quick review! 🙌 Yes, I'm happy to open a PR with the fix, including a regression test for the sliced sub-event start time (asserting subsequent slices start at the next day's 00:00 rather than 23:59). I'll get that ready.

[ago1776]

Opened #4208 with the one-line fix plus an electron regression test (a timed multi-day event spanning several midnights; asserts every slice starts at 00:00 and never 23:59 — fails without the fix). Thanks for the quick review! 🙏

[ago1776]

Fixed via #4208 (merged into develop). The one-line fix in sliceMultiDayEvents now sets sliced sub-events to next-day 00:00 instead of 23:59, with a regression test covering the case.