`on_date` translation is problematic

[silverwind]

Description

As seen on Crowdin, translators have a hard time translating the on alone in on <date> phrases because some languages don't have a concept of such a word. We should evaluate if there are alternatives and whether we can somehow translate the whole phrase.

[yardenshoham]

Blocked by #23863?

[lunny]

Blocked by #23863?

I don't think so.

[silverwind]

I think the solution will be to never have the time element emit this "on", and instead render the element into the translation string via a token. I also checked the JS Intl API, it seems it also can not emit a "on", it can emit a "at" but that does not help us.

[yardenshoham]

One way to avoid on is to use tense=past whenever possible. Ref #24106

[wxiaoguang]

I would suggest to remove the on prefix from TimeSince, if it is not necessary.

Is there a strong reason to keep it?

[silverwind]

In some contexts the on makes sense to form sentences:

I agree on needs to be removed from TimeSince (and in turn <relative-time>), and these sentences should be formed based on a translation string on %s. where %s than renders the TimeSince.

[yardenshoham]

about the last sentence. Not TimeSince, an absolute datetime is more like template "shared/datetime/short"

[silverwind]

Though, the challenge ist that <relative-time> may or may not output the on <date> format, depending on how far back the date is. So I guess the backend must know as well when the on appears to emit the correct translation to avoid on 5 days ago.

[yardenshoham]

Threshold is configurable

[wxiaoguang]

Quote my comment from #24106

In history , IIRC the TimeSince always used relative date, then <relative-time> changed the behavior.

Now, we just make <relative-time> always use tense=past, then it behaves like the old TimeSince , then everything should be fine, and just like before.

Then we do not need the on either.

Correct me if I am wrong.