A modest JavaScript framework for the HTML you already have.
This will appeal to anyone who is apprehensive about JavaScript being required to generate HTML, yet wants a modern framework to help with modern problems, like state management.
I wonder if this would be a good answer for things like WordPress or CraftCMS themes that are designed to be server side but, like any site, could benefit from client-side JavaScript enhancements. Stimulus isn’t really built to handle SPAs, but instead pair with Turbolinks. That way, you’re still changing out page content with JavaScript, but all the routing and HTML generation is server side. Kinda old school meets new school.
