svelte/test/runtime/samples/binding-input-checkbox-deep-contextual/main.svelte

<script>
	export let items;
	export let numCompleted;

	$: numCompleted = items.reduce((total, item) => {
		return total + (item.completed ? 1 : 0);
	}, 0);
</script>

{#each items as item}
	<div><input type='checkbox' bind:checked={item.completed}><p>{item.description}</p></div>
{/each}

<p>{numCompleted} completed</p>