I recently wrote a 10 line script that had to work with date arithmetic *, and while importing URLs is pretty cool, it still was the same shit of spending 80% of the time it took to write the code browsing and evaluating multiple third party date libraries to find one good enough for my use case. So in practice the only improvement Deno had over Node in that example was that I didn't have to run `npm install`. Yay, great.
*: adding two dates together, converting to and from UTC, given a Date find the next midnight. And as expected the most popular JS library couldn't even get one of these simple tasks correct, there's a bug report open since 2017. Incredible stuff from this ecosystem.
I have also used Howard Hinnant's C++ date-time lib: https://github.com/HowardHinnant/date It is also very good. (He was the guy behind move semantics in C++ 11.)
In Python, the stdlib has a function to get UTC now, that does not include UTC timezone... so it weirdly and surprisingly acts like local time zone! There is endless shit-posting about it. I feel bad for Guido van Rossum et al. To be fair, the original Java date-time lib was horrible, so Joda-Time was created. And JDBC (Java database) dates are still horrible.