This is so cool.
"Starbeam is Universal Reactivity
Starbeam is a library that allows you to write reactive code in a framework agnostic way. This means that you can write your code once, and use it with any framework that has a Starbeam renderer.
At the moment, Starbeam has renderers for React and Preact. We've also built a proof of concept renderer for Svelte and we're working on a Vue renderer."