mrujs might be of interest

Sorry for opening an issue, but you don't have any other contact information listed.

Given the stated purpose of this library, you might be excited to know that there's actually a successor to UJS that hits all of the right notes: https://mrujs.com

It's 99% drop-in compatible except for things like swapping out XHR for fetch. It fixes the major problems with rails-ujs (validation errors get morphed into the page!) and even has a plugin system.