[fix]: Add support for TrustedTypes in Svelte

.changeset/witty-lies-happen.md

@@ -0,0 +1,5 @@
+---
+'svelte': minor
+---
+
+Add TrustedTypes support

packages/svelte/package.json

@@ -166,6 +166,7 @@
     "@jridgewell/sourcemap-codec": "^1.5.0",
     "@sveltejs/acorn-typescript": "^1.0.5",
     "@types/estree": "^1.0.5",
+    "@types/trusted-types": "^2.0.7",
     "acorn": "^8.12.1",
     "aria-query": "^5.3.1",
     "axobject-query": "^4.1.0",

packages/svelte/src/internal/client/dom/blocks/html.js

@@ -97,7 +97,7 @@ export function html(node, get_value, svg = false, mathml = false, skip_warning
 		// Don't use create_fragment_with_script_from_html here because that would mean script tags are executed.
 		// @html is basically `.innerHTML = ...` and that doesn't execute scripts either due to security reasons.
 		/** @type {DocumentFragment | Element} */
-		var node = create_fragment_from_html(html);
+		var node = create_fragment_from_html(html, /*untrusted=*/ true);
 
 		if (svg || mathml) {
 			node = /** @type {Element} */ (get_first_child(node));

packages/svelte/src/internal/client/dom/reconciler.js

@@ -1,6 +1,27 @@
+/** @import { TrustedTypePolicy } from 'trusted-types' */
+
+const policy = /* @__PURE__ */ globalThis?.window?.trustedTypes?.createPolicy(
+	'svelte-trusted-html',
+	{
+		/** @param {string} html */
+		createHTML: (html) => {
+			return html;
+		}
+	}
+);
+
 /** @param {string} html */
-export function create_fragment_from_html(html) {
+function create_trusted_html(html) {
+	return /** @type {string} */ (policy?.createHTML(html) ?? html);
+}
+
+/**
+ * @param {string} html
+ * @param {boolean} untrusted
+ */
+export function create_fragment_from_html(html, untrusted = false) {
 	var elem = document.createElement('template');
-	elem.innerHTML = html.replaceAll('<!>', '<!---->'); // XHTML compliance
+	html = html.replaceAll('<!>', '<!---->'); // XHTML compliance
+	elem.innerHTML = untrusted ? html : create_trusted_html(html);
 	return elem.content;
 }