Allow to render TrustedHTML objects similar to SafeString

packages/@glimmer-workspace/integration-tests/package.json

@@ -29,6 +29,7 @@
     "@simple-dom/document": "^1.4.0",
     "@simple-dom/serializer": "^1.4.0",
     "@simple-dom/void-map": "^1.4.0",
+    "@types/trusted-types": "^2.0.7",
     "js-reporters": "^2.1.0",
     "qunit": "^2.19.4",
     "simple-html-tokenizer": "^0.5.11"

packages/@glimmer-workspace/integration-tests/test/trusted-html-test.ts

@@ -0,0 +1,53 @@
+import type { TrustedTypePolicy, TrustedTypesWindow } from 'trusted-types/lib';
+
+import { jitSuite, RenderTest, test } from '..';
+
+let policy: TrustedTypePolicy | undefined;
+if (typeof window !== 'undefined') {
+  let trustedTypes = (window as unknown as TrustedTypesWindow).trustedTypes;
+  if (trustedTypes?.createPolicy) {
+    policy = trustedTypes.createPolicy('test', {
+      createHTML: (s: string) => s,
+      createScript: (s: string) => s,
+      createScriptURL: (s: string) => s,
+    });
+  }
+}
+
+export class TrustedHTMLTests extends RenderTest {
+  static suiteName = 'TrustedHTML';
+
+  @test
+  'renders TrustedHTML similar to SafeString'() {
+    if (!policy) return;
+
+    let html = '<b>test\'"&quot;</b>';
+    this.registerHelper('trustedHTML', () => {
+      return policy?.createHTML(html);
+    });
+
+    this.render('<div>{{trustedHTML}}</div>');
+    this.assertHTML('<div><b>test\'""</b></div>');
+    this.assertStableRerender();
+  }
+
+  @test
+  'renders TrustedHTML in attribute context as string'() {
+    if (!policy) return;
+
+    let html = '<b>test\'"&quot;</b>';
+    this.registerHelper('trustedHTML', () => {
+      return policy?.createHTML(html);
+    });
+
+    // To keep rendering behavior consistent with SafeString
+    // trustedHTML is not encoded or decoded in attribute value context.
+    // It is set as string, that means result value can contain HTML enitites.
+    // TrustedHTML value must not escape from HTML attribute value context to prevent XSS.
+    this.render('<a title="{{trustedHTML}}">{{trustedHTML}}</a>');
+    this.assertHTML('<a title="<b>test\'&quot;&amp;quot;</b>"><b>test\'""</b></a>');
+    this.assertStableRerender();
+  }
+}
+
+jitSuite(TrustedHTMLTests);

packages/@glimmer/interfaces/package.json

@@ -20,7 +20,8 @@
     "test:types": "tsc --noEmit"
   },
   "dependencies": {
-    "@simple-dom/interface": "^1.4.0"
+    "@simple-dom/interface": "^1.4.0",
+    "@types/trusted-types": "^2.0.7"
   },
   "devDependencies": {
     "@glimmer-workspace/build-support": "workspace:^",

packages/@glimmer/opcode-compiler/lib/opcode-builder/helpers/stdlib.ts

@@ -74,6 +74,11 @@ export function StdAppend(
         op(Op.AppendSafeHTML);
       });
 
+      when(ContentType.TrustedHTML, () => {
+        op(Op.AssertSame);
+        op(Op.AppendHTML);
+      });
+
       when(ContentType.Fragment, () => {
         op(Op.AssertSame);
         op(Op.AppendDocumentFragment);

packages/@glimmer/runtime/lib/compiled/opcodes/content.ts

@@ -11,7 +11,14 @@ import { isObject } from '@glimmer/util';
 import { ContentType, CurriedType, Op } from '@glimmer/vm';
 
 import { isCurriedType } from '../../curried-value';
-import { isEmpty, isFragment, isNode, isSafeString, shouldCoerce } from '../../dom/normalize';
+import {
+  isEmpty,
+  isFragment,
+  isNode,
+  isSafeString,
+  isTrustedHTML,
+  shouldCoerce,
+} from '../../dom/normalize';
 import { APPEND_OPCODES } from '../../opcodes';
 import DynamicTextContent from '../../vm/content/text';
 import { CheckReference } from './-debug-strip';
@@ -32,6 +39,8 @@ function toContentType(value: unknown) {
     return ContentType.Helper;
   } else if (isSafeString(value)) {
     return ContentType.SafeString;
+  } else if (isTrustedHTML(value)) {
+    return ContentType.TrustedHTML;
   } else if (isFragment(value)) {
     return ContentType.Fragment;
   } else if (isNode(value)) {

packages/@glimmer/runtime/lib/dom/normalize.ts

@@ -1,4 +1,5 @@
 import type { Dict, SimpleDocumentFragment, SimpleNode } from '@glimmer/interfaces';
+import type { TrustedHTML, TrustedTypesWindow } from 'trusted-types/lib';
 
 export interface SafeString {
   toHTML(): string;
@@ -43,6 +44,18 @@ export function isEmpty(value: unknown): boolean {
   return value === null || value === undefined || typeof (value as Dict).toString !== 'function';
 }
 
+let isHTML: ((value: unknown) => boolean) | undefined;
+if (typeof window !== 'undefined') {
+  let trustedTypes = (window as unknown as TrustedTypesWindow).trustedTypes;
+  if (trustedTypes?.isHTML) {
+    isHTML = trustedTypes?.isHTML.bind(trustedTypes);
+  }
+}
+
+export function isTrustedHTML(value: unknown): value is TrustedHTML {
+  return isHTML ? isHTML(value) : false;
+}
+
 export function isSafeString(value: unknown): value is SafeString {
   return typeof value === 'object' && value !== null && typeof (value as any).toHTML === 'function';
 }

packages/@glimmer/runtime/package.json

@@ -43,7 +43,8 @@
     "@glimmer/util": "workspace:^",
     "@glimmer/validator": "workspace:^",
     "@glimmer/vm": "workspace:^",
-    "@glimmer/wire-format": "workspace:^"
+    "@glimmer/wire-format": "workspace:^",
+    "@types/trusted-types": "^2.0.7"
   },
   "devDependencies": {
     "@glimmer-workspace/build-support": "workspace:^",

packages/@glimmer/vm/lib/content.ts

@@ -7,4 +7,5 @@ export const ContentType = {
   Fragment: 5,
   Node: 6,
   Other: 8,
+  TrustedHTML: 9,
 } as const;