[fix] don't strip type="application/.." tags

.changeset/cyan-pianos-bake.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/package': patch
+---
+
+[fix] don't strip `type="application/.."` tags

packages/package/src/utils.js

@@ -49,7 +49,11 @@ export function resolve_lib_alias(file, content, config) {
  */
 export function strip_lang_tags(content) {
 	return content
-		.replace(/(<!--[^]*?-->)|(<script[^>]*?)\s(?:type|lang)=(["']).*?\3/g, '$1$2')
+		.replace(
+			/(<!--[^]*?-->)|(<script[^>]*?)\s(?:type|lang)=(["'])(.*?)\3/g,
+			// things like application/ld+json should be kept as-is. Preprocessed languages are "ts" etc
+			(match, s1, s2, _, s4) => (s4.startsWith('application/') ? match : (s1 ?? '') + (s2 ?? ''))
+		)
 		.replace(/(<!--[^]*?-->)|(<style[^>]*?)\s(?:type|lang)=(["']).*?\3/g, '$1$2');
 }
 

packages/package/test/fixtures/typescript/expected/Plain.svelte

@@ -2,3 +2,7 @@
 	/** @type {import('./foo').Foo} */
 	export let foo;
 </script>
+
+<svelte:head>
+  <script type="application/ld+json">{JSON.stringify(jsonLd)}</script>
+</svelte:head>

packages/package/test/fixtures/typescript/src/lib/Plain.svelte

@@ -2,3 +2,7 @@
 	/** @type {import('./foo').Foo} */
 	export let foo;
 </script>
+
+<svelte:head>
+  <script type="application/ld+json">{JSON.stringify(jsonLd)}</script>
+</svelte:head>

packages/package/test/fixtures/typescript/svelte.config.js

@@ -1,5 +1,7 @@
 import preprocess from 'svelte-preprocess';
 
 export default {
-	preprocess: preprocess()
+	preprocess: preprocess({
+		preserve: ['ld+json']
+	})
 };