Basic Svelte app not loading when using DatePicker

[Arsenalist]

I have this in my component:

<script lang="ts">
    import DatePicker from "@deboxsoft/svelte-datepicker/src/components/DatePicker.svelte";
</script>
<DatePicker/>

And I get this error on startup:

import App from './App.svelte';

const app = new App({
	target: document.body,
	props: {
//		name: 'world'
	}
});

export default app;

The app loads fine if I get rid of the <DatePicker/>.