Using getLocalTimeZone() in RSC's?

[J4v4Scr1pt]

When you use methods like parseAbsolute(), today(), isToday() etc. they require you to provide an timeZone. The docs suggest getLocalTimeZone().

Using NextJs and creating RSC's you may sometime need use these methods and getLocalTimeZone uses new Intl.DateTimeFormat().resolvedOptions().timeZone under the hood. I would think this uses the server timeZone then.
What is the suggested way of providing the correct user timeZone doing SSR?
Maybe a stupid question, but I would to hear what you think. 😅

[reidbarber]

You should be able to set a cookie, then read it from the header in RSCs: https://nextjs.org/docs/app/api-reference/functions/cookies

[J4v4Scr1pt]

Interesting suggestion, I actully do that to provide the user locale to i18Next.
In my case I'm using NextUI which is built upon react-spectrum. You need to have an NextUI wrapper to use theming, navigation etc. but you also provide an locale that is consumed by the react-aria I18nProvider under the hood.

Long story short, could the I18nProvider's locale e.g en-US used somehow to determine the timeZone? or are they two completely seperate things?

[reidbarber]

They are separate things, but you can get a list of supported timezones by locale: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Locale/getTimeZones

I haven't tested this, so not sure how reliable it is.

[J4v4Scr1pt]

Ok thx again. I will play arround with this and test. But now I know a bit more how we should think.