I've used gleam for a toy project in uni, and AoC
My main friction point is that the Int type maps to different concepts in erlang and js
In erlang it's a arbitrary precision Int
In js it the js number type, which is a 64bit float iirc.
Also recursion can hit limits way sooner in js.
For me, my code rarely ran in both js and erlang. But could be skillissue