$host
在将组件编译为自定义元素时，$host 符文提供了对主机元素的访问权限，使您可以（例如）分派自定义事件（演示)
步进器
<svelte:options customElement="my-stepper" />
<script>
function dispatch(type) {
$host().dispatchEvent(new CustomEvent(type));
}
</script>
<button onclick={() => dispatch('decrement')}>decrement</button>
<button onclick={() => dispatch('increment')}>increment</button>应用
<script>
import './Stepper.svelte';
let count = $state(0);
</script>
<my-stepper
ondecrement={() => count -= 1}
onincrement={() => count += 1}
></my-stepper>
<p>count: {count}</p>