An introduction to svelte-global-typescript

svelte-global-typescript removes the need to repeat lang="ts" in every Svelte component. It is both a Vite plugin and a Svelte markup preprocessor, so one helper can cover builds and editor diagnostics.

src/lib/greeting.svelte

<script>
	let { name }: { name: string } = $props();
</script>

<h1>Hello, {name satisfies string}</h1>

The source stays compact, while Svelte receives the equivalent of a TypeScript script during preprocessing.

The transform applies to .svelte and .sv files. It adds lang="ts" to script tags without a language, adds an empty TypeScript script when a component only uses TypeScript in markup, and preserves every explicit language attribute.

<script lang="js">
	let name = "JavaScript on purpose";
</script>

That explicit lang="js" remains an escape hatch for individual scripts or components.

Introduction