It's been a long time dream for me since about 2013 when I started getting deep into Ruby and Rails, to be able to write Ruby code for the frontend instead of JavaScript. I was a lover and adopter of CoffeeScript (which had it's flaws and imperfections), but that mostly got killed by ES6, and in truth ES7 and beyond made javascript a whole lot more tolerable so less need/motivation to use Ruby on frontend.
I wrote some PoCs with Opal[1] that felt pretty good to write, but the overhead was rough (this was many years ago so things might be different now) and I never really felt like I didn't have to know about or care about the underlying javascript. I tend to discard leaky abstractions as I feel they often add more complexity than they were meant to cover in the first place.
Has anybody used this or Opal or anything else? What is the state of "write your frontend in Ruby" nowadays?