How to create global custom directives in Vue 3 with Typescript

I created the app with the latest Vue cli and I'm trying to register a global custom directive with no success. Can someone maybe tell me what I'm doing wrong here?

import { createApp } from "vue";
import App from "./App.vue";
import "./registerServiceWorker";
import router from "./router";
import store from "./store";

const app = createApp(App);

app.directive("highlight", {
  beforeMount(el, binding, vnode) {
    el.style.background = binding.value;
  },
});

app
  .use(store)
  .use(router)
  .mount("#app");

The directive v-highlight should have a value of type string like :

     <h3 v-highlight="'yellow'">highlighted using yellow</h3>
    <h3 v-highlight="'#4455ff'">highlighted using blue</h3>

if you provided it without '' you would have the following error :

[Vue warn]: Property "yellow" was accessed during render but is not defined on instance

This means that your directive is looking for a data or a computed property called yellow which is not defined in your script.

LIVE DEMO

I raised this issue and they will fix that syntax error