Intl.DateTimeFormat - wrong long weekday

[arxeiss]

• Version: v12.9.0
• Platform: Ubuntu 19.04 Linux 5.0.0-25-generic GitHub issue management node#26-Ubuntu SMP Thu Aug 1 12:04:58 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

I think it is related to nodejs/node#26790 because when no full ICU is installed and I have different locale, weekday long always returns short.

new Intl.DateTimeFormat('cs-CZ', { weekday: 'long', timeZone: 'UTC' }).formatToParts(new Date('2017-10-30'))[0].value; // Mon

new Intl.DateTimeFormat('en-US', { weekday: 'long', timeZone: 'UTC' }).formatToParts(new Date('2017-10-30'))[0].value; // Monday

If localisation for cs-CZ is not installed, it returns fallback English name? Because for months it works differently, for cs-CZ it returns M10

[bnoordhuis]

Without full-icu node only knows about en-US so yes.

I'm going to close this as answered but I can move it to nodejs/help if you have follow-up questions.

[arxeiss]

@bnoordhuis Not it is not answered.. If fallback to english is used, why then weekday long is Mon and not Monady - so it is short, not long?

And for month is returned M10 instead of english fallback?

[bnoordhuis]

The answer to your questions is mostly 'because ICU' - that's the library that implements the i18n logic, not node or V8 itself.

[arxeiss]

OK, according to issue into which I referenced before (nodejs/node#26790) I thought, that this is nodejs thing. But if it has nothing to do with node itself, than there is no place to fix it.

So probably it can stay closed - thank you