[jwalton]

Welllll… “works right now” is perhaps an overly strong assertion when it comes to day.js. I was working on a library we use for parsing "schedules" (like, alarm turns on at 9:00pm on Thursday, and off again at 7:00am on Friday). I was doing things like computing the number of seconds until the next scheduled transition. I tried switching from moment to day.js, and my unit tests immediately failed. Within a couple of hours I’d opened two bugs [1][2], both related to incorrect behaviour in corner cases (like generating the incorrect date when near a daylight saving time transition).

The fact that it only took me a few hours to find these suggests there are plenty more bugs like these to find. The fact that these bugs have been open since the start of March with no movement on them suggests they aren’t too interested in correct behaviour (or perhaps they’re just your typical under-staffed open source project).

Maybe I just got super unlucky and ran into the only two bugs here… but it’s not likely.

Luxon and moment.js both handled these cases perfectly. If you’re looking to move from whatever you’re using now, and you can’t wait for the new standard, I’d pick one of those.

[1]: https://github.com/iamkun/dayjs/issues/1816

[2]: https://github.com/iamkun/dayjs/issues/1817