[trustedTypes]: Add TrustedTypes support to 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/reconciler.js

@@ -1,6 +1,25 @@
+/** @import { TrustedTypePolicy } from 'trusted-types' */
+
+/** @type {Pick<TrustedTypePolicy, 'createHTML'> | undefined} */
+let policy;
+
+if (globalThis?.window?.trustedTypes) {
+	policy = globalThis.window.trustedTypes.createPolicy('svelte-trusted-html', {
+		/** @param {string} html */
+		createHTML: (html) => {
+			return html;
+		}
+	});
+}
+
+/** @param {string} html */
+function create_trusted_html(html) {
+	return /** @type {string} */(policy?.createHTML(html) ?? html);
+}
+
 /** @param {string} html */
 export function create_fragment_from_html(html) {
 	var elem = document.createElement('template');
-	elem.innerHTML = html.replaceAll('<!>', '<!---->'); // XHTML compliance
+	elem.innerHTML = create_trusted_html(html.replaceAll('<!>', '<!---->')); // XHTML compliance
 	return elem.content;
 }

pnpm-lock.yaml

@@ -71,6 +71,9 @@ importers:
       '@types/estree':
         specifier: ^1.0.5
         version: 1.0.6
+      '@types/trusted-types':
+        specifier: ^2.0.7
+        version: 2.0.7
       acorn:
         specifier: ^8.12.1
         version: 8.14.0
@@ -797,6 +800,9 @@ packages:
   '@types/semver@7.5.6':
     resolution: {integrity: sha512-dn1l8LaMea/IjDoHNd9J52uBbInB796CDffS6VdIxvqYCPSG0V0DzHp76GpaWnlhg88uYyPbXCDIowa86ybd5A==}
 
+  '@types/trusted-types@2.0.7':
+    resolution: {integrity: sha512-ScaPdn1dQczgbl0QFTeTOmVHFULt394XJgOQNoyVhZ6r2vLnMLJfBPd53SB52T/3G36VI1/g2MZaX0cwDuXsfw==}
+
   '@typescript-eslint/eslint-plugin@8.26.0':
     resolution: {integrity: sha512-cLr1J6pe56zjKYajK6SSSre6nl1Gj6xDp1TY0trpgPzjVbgDwd09v2Ws37LABxzkicmUjhEeg/fAUjPJJB1v5Q==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
@@ -3059,6 +3065,8 @@ snapshots:
 
   '@types/semver@7.5.6': {}
 
+  '@types/trusted-types@2.0.7': {}
+
   '@typescript-eslint/eslint-plugin@8.26.0(@typescript-eslint/parser@8.26.0(eslint@9.9.1)(typescript@5.5.4))(eslint@9.9.1)(typescript@5.5.4)':
     dependencies:
       '@eslint-community/regexpp': 4.12.1