Event segments one day too short when timezone is set - Githubissues

jquense / react-big-calendar

gcal/outlook like calendar component

http://jquense.github.io/react-big-calendar/examples/index.html

MIT License

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Event segments one day too short when timezone is set #2659

Open evanbrooks-codaio opened 1 month ago

evanbrooks-codaio commented 1 month ago

Check that this is really a bug

[X] I confirm

Reproduction link

https://codesandbox.io/p/sandbox/react-big-calendar-example-forked-wc6sts

Bug description

Configure a localizer with a timezone to the east of the browser's current timezone.
Create an event that spans multiple weeks
Display a month view. Note that the event segments are not spanning correctly.

I believe this may be the same issue as #2425 , however it appears to happen consistently in any timezone, and consistently with either the moment or luxon localizers. feel free consolidate if this is a duplicate.

Expected Behavior

Segments include the last day of the event.
Segments extend to the last day of the week when multi-week

Actual Behavior

Segments ends the day before the end of the event.
Segments omit last day of the week when multi-week. (For example, ending on friday if the last day of the week is saturday).

react-big-calendar version

1.14.1

React version

18.2.0

Platform/Target and Browser Versions

macOS 14.4, Chrome 129

Validations

[X] Read the docs.
[X] Check that there isn't already an issue that request the same feature to avoid creating a duplicate.
[X] Make sure this is a react-big-calendar issue and not an implementation issue

Would you like to open a PR for this bug?

[X] I'm willing to open a PR

evanbrooks-codaio commented 1 month ago

The issue appears to be with the getBrowserTzOffset in the localizers, ie here for luxon. This configures the segmentOffset here and is used to explictly subtract the width of the segment here:

https://github.com/jquense/react-big-calendar/blob/856dddf8938a0e0e543b4ef026e0ca3cdcce1071/src/utils/eventLevels.js#L26-L28

It seems like this is subtracting "1" in situations where the segments are already correct. I've found that simply removing the segmentOffset appears to resolve the issue in my test case. I'm not sure exactly when it is necessary to subtract 1 (if ever?), but it seems to happening more often than it should.