It uses svelte-preprocess-react
to preprocess the @shopify/polaris
components. This is not a good idea, but it works for now. It is not meant to be used in production.
https://www.npmjs.com/package/svelte-preprocess-react
npm install shopify-polaris-svelte
// +layout.svelte
<script>
import en from '@shopify/polaris/locales/en.json';
import { AppProvider } from 'shopify-polaris-svelte';
</script>
<AppProvider i18n={en}>
<slot />
</AppProvider>