Add custom timezone support to moment localizer

[ariel22411]

Add a custom timezone to moment localizer

#2400

[cutterbl]

I like the track you're on, but unfortunately this will not work. It assumes that all users of Big Calendar, using moment, are also using moment-timezone. Many implementations only use moment without timezone support, so initializing a date with moment.tz() will fail for them, as they don't have the necessary dependencies to extend moment.

A better option might be to

• If timezone is passed as an argument, then
• test if moment.tz is a thing, and
• if not, log a console error, but gracefully ignore, and use moment() on it's own

[ariel22411]

I changed according to your review @cutterbl

[cutterbl]

@ariel22411 One final request here is to add an example to the documentation, in using the momentLocalizer in this per instance timezone matter, with an included brief explanation on possible use case for doing so.

[ariel22411]

sorry for the delay, now its okay? @cutterbl

[tinsaeopus1io]

We've been using this for months, and it has been working great. But now we are having issues on the calendar week view for dates on the week of dst, where the time gutter is off by 1 hour. Please let us know if anyone experienced this issue, and has a fix or workaround @samopus1io @canopus1io

[canopus1io]

here are a couple code sandbox examples:
America/Los_Angeles DST example
Europe/London DST example (looks correct in all cases if you have your system timezone set to Europe/London)

there are two localizer versions to compare here (moment-tz is the localizer in this PR, moment-tz modified is with one tweak that seems to fix the gutter time labels)

here is the tweak diff for the modified version:

[canopus1io]

@ariel22411 thoughts on this change? (only seems to be different when DST shift is not included in displayed time range for the week)

[ariel22411]

@tinsaeopus1io @canopus1io
I have a solution,
see this change:
https://github.com/jquense/react-big-calendar/pull/2406/files#diff-bcdd39e4dfd1f46fb8f9091a9ac5c14c56b51a9006bcfc6dcf9bac1272212bc3R84

[ariel22411]

The next problem is the DST slots time: (see if you can help me with that) @cutterbl