How to make frint work with custom elements or custom element lib (lit-html, atomico etc)?

[kristianmandrup]

I'm trying to make frintjs work with atomico which uses reactive custom elements (aka web components) and seems a more modern and natural fit for frintjs.

Would much appreciate some advice for how to make a frint adapter for a custom elements library.
Does the component have to be a class? The modern way seems to be a more functional approach, such as with React 16 using hooks. Atomico also uses hooks.