utcToZonedTime returns wrong value for Android

[Gabi1M]

Hi all,

I'm trying to parse an ISO 8601 string to zoned date time, but on android it returns a wrong value. On iOS it works just fine.
The string I'm trying to parse is 2022-04-19T19:00:00+05:00.

I'm using the following versions:

• date-fns: 2.28.0
• date-fns-tz: 1.1.2

The code I'm testing with is:

import { parseISO } from 'date-fns';
import { format, utcToZonedTime } from 'date-fns-tz';

const test = '2022-04-19T19:00:00+05:00';
const parsed = parseISO(test);
const result = utcToZonedTime(parsed, TIME_ZONE);

console.log(`Date to parse: ${test}`);
console.log(`Parsed: ${format(parsed, 'dd MMMM yyyy HH:mm zzz')}`);
console.log(`Zoned: ${format(result, 'dd MMMM yyyy HH:mm zzz')}`);

My local timezone is: Europe/Bucharest GMT+2/GMT+3 DST
TIME_ZONE is: Asia/Karachi GMT + 5

The output is as follows:

• iOS
  Date to parse: 2022-04-19T19:00:00+05:00
  Parsed: 19 April 2022 17:00 GMT+3
  Zoned: 19 April 2022 19:00 GMT+3
• Android
  Date to parse: 2022-04-19T19:00:00+05:00
  Parsed: 19 April 2022 17:00 '
  Zoned: 19 April 2022 07:00 '

Instead of outputing 19 for the hour, it outputs 07, regardless of HH being specified in the format string. This interferes with date calculations in our app and is producing different behaviours on iOS and Android.
I have tried on multiple android versions, on both real devices and emulator, and the result is consistent on all of them.

[marnusw]

Please see if the info in #59 solves your issue and if so perhaps consider contributing it to the readme since it seems to be a recurring problem. You could also try a polyfill for Intl on Android: https://formatjs.io/docs/polyfills

[Gabi1M]

Thanks for the response.
Indeed, the issue you linked above solves the problem if the app doesn't use hermes. Sadly, we do use it, and disabling it is not really an option.
We do use this polyfill to include the necessary features

[marnusw]

That is unfortunate. Still, this does seem like an "Inlt doesn't work on Android" problem rather than a problem with date-fns-tz. It might be useful to try using the Intl API functions directly first until you can get that to work in an app using Hermes. I won't have time to figure this out in the near future. If you solve it please post the solution!

[marnusw]

@Gabi1M have you managed to get Intl working on Android with Hermes? I was wondering if it might work to delete window.Intl before adding a polyfill. That way everything should happen in JS. It'll be messy, but it might work in the meantime.

[marnusw]

I've added a note to the readme on usage with Android. Closing this until there is Intl support for Hermes.

[jean-marc-cp]

Hermes has support for Intl on both iOS and Android as of RN 70.
facebook/hermes#23 (comment)