Svelte 附带几个反应类，你可以用它们代替 JavaScript 内置对象 — 即 Map、Set、Date、URL 和 URLSearchParams。
¥Svelte ships with several reactive classes that you can use in place of JavaScript built-in objects — namely Map, Set, Date, URL and URLSearchParams.
在这个练习中，我们可以使用 $state(new Date()) 声明 date，并在 setInterval 中重新分配它。但更好的替代方案是从 svelte/reactivity 使用 SvelteDate：
¥In this exercise, we could declare date using $state(new Date()) and reassign it inside the setInterval. But a nicer alternative is to use SvelteDate from svelte/reactivity:
App
<script>
import { SvelteDate } from 'svelte/reactivity';
let date = new SvelteDate();
// ...
</script><script lang="ts">
import { SvelteDate } from 'svelte/reactivity';
let date = new SvelteDate();
// ...
</script>上一页 下一页
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<script>
let date = new Date();
const pad = (n) => n < 10 ? '0' + n : n;
$effect(() => { const interval = setInterval(() => {date.setTime(Date.now());
}, 1000);
return () => {clearInterval(interval);
};
});
</script>
<p>The time is {date.getHours()}:{pad(date.getMinutes())}:{pad(date.getSeconds())}</p>