svelte/test/runtime/samples/after-render-triggers-update/main.html

<script>
	import { afterUpdate } from 'svelte';

	export let a;
	export let b;

	export let value;

	afterUpdate(() => {
		b.textContent = a.textContent;
	});
</script>

<p bind:this={a}>{value}</p>
<p bind:this={b}></p>