<svelte:options customElement="my-app" /> <script> import { onMount, onDestroy } from "svelte"; let el; let parentEl; onMount(() => { parentEl = el.parentNode.host.parentElement; return () => { parentEl.dataset.onMountDestroyed = true; }; }); onDestroy(() => { parentEl.dataset.destroyed = true; }); </script> <div bind:this={el} />