usage:

import setupPersistentSignal from "https://esm.town/v/novari/persistentSignal";
import signals from "https://esm.sh/@preact/signals"; // or any other compatible library like @preact/signals-core, @preact/signals-react etc
import { useLiveSignal } from "https://esm.sh/@preact/signals/utils"; // if you want to use your persistent signals as local signals

const persistentSignal = setupPersistentSignal(signals);

const userName = persistentSignal("username", "USERNAME-UNKNOWN"); //uses localStorage, so all values are turned into strings

function App(){
  const user = useLiveSignal(userName);
  if (user == "USERNAME-UNKNOWN") return ( <RequestName signal={user}/> );
  else return ( <Greeting signal={user}/> );
}

(in theory, idk what's up with the random v3.module.town and esm.town/x/ and esm.town/v/ etc etc)