[pfg_]

If you just want to make vanilla js reactive, you can use solid js but without jsx (or something similar). This library could likely do the same.

    import { createRoot, createSignal, createRenderEffect } from "solid-js";  

    function SomeComponent() {  
      const [count, setCount] = createSignal(0);  

      const result = document.createElement("button");  
      createRenderEffect(() => result.textContent = "++ (" + count() + ")");  
      result.onclick = () => setCount(count() + 1);  
      return result;  
    }  


    createRoot(cleanup => {  
      const appv = document.getElementById("app");  
      appv.appendChild(SomeComponent());  
    });