svelte/documentation/tutorial/16-special-elements/09-svelte-options/app-b/Todo.svelte

<svelte:options immutable={true} />

<script>
	import { afterUpdate } from 'svelte';
	import flash from './flash.js';

	export let todo;

	let button;

	afterUpdate(() => {
		flash(button);
	});
</script>

<!-- the text will flash red whenever
     the `todo` object changes -->
<button bind:this={button} type="button" on:click>
	{todo.done ? '👍' : ''}
	{todo.text}
</button>

<style>
	button {
		all: unset;
		display: block;
		cursor: pointer;
		line-height: 1.5;
	}
</style>