The playground you asked for has already helped me file and fix a bug https://github.com/yippee-fun/morphlex/issues/38 in my brief review of Morphlex.

See https://dm.rt.ht

Just updated to demonstrate what `moveBefore()` brings to the table!!

Try moving the clock.gif line up/down with Alt+↑ and Alt+↓!

(it is very nascent, and I am on a plane with shaky Wi-Fi, so I will give it the love it deserves in a couple of days: compare all libraries with each other, add a benchmark, etc.)