Inconsistent use of "yesterday"

Using relative-time-element v4.4.5.

I am in a UTC-5 time zone. The current time for me is April 30 1:53PM (2025-04-30 18:53 UTC).

I've set up a test page at https://greasyfork.org/en/relative_date_test to show the last 48 hours of ``. Here is what I see:


- 0 hours ago shows "now", no issue.
- 1 - 13 hours ago (Apr 30 for me) - shows as "x hours ago", no issue.
- 14 - 20 hours ago (Apr 29 for me) - shows as "x hours ago", could also show as "yesterday", but that's fine.
- 21 - 35 hours ago (Apr 29 for me) - shows as "yesterday", no issue.
- **36 - 37 hours ago (Apr 29 for me) - shows as "2 days ago".**
- 38 - 48 hours ago (Apr 28 for me) - shows as "2 days ago", no issue.

36 and 37 hours ago for me is Apr 29 12:53AM and 1:53AM, which is still "yesterday", not "2 days ago". Especially weird that then Apr 29 2:53AM _is_ "yesterday".

I imagine that maybe "1.5 days ago" is getting rounded up to "2 days ago", but "yesterday" is a concept of calendar dates and not a number of hours, so there's no reason to stop using that term until it's no longer 1 calendar day ago.

Start with the linked relative_date_test page and reproduce the reported behavior using relative-time-element v4.4.5 in the UTC-5 example. Trace the relative-time rendering entry point and verify that timestamps 36–37 hours old still display “yesterday” when they fall on the previous local calendar date, while timestamps from two calendar dates ago display “2 days ago”.

索引モデルが issue の本文から書いたものです。