fix(template-require-iframe-title): address Copilot review — use strict, comment count, doc wrap, hbs parity

Author: johanrd

docs/rules/template-require-iframe-title.md

@@ -39,8 +39,8 @@ This rule **forbids** the following:
 Whitespace-only `title` (`"   "`) is flagged by default as an
 authoring-hygiene check: HTML and ACCNAME technically permit it (step 2I
 doesn't trim), but a whitespace-only accessible name is useless in
-practice. Suppress this specific strictness via `allowWhitespaceOnlyTitle:
-true` if your codebase needs it.
+practice. Suppress this specific strictness via
+`allowWhitespaceOnlyTitle: true` if your codebase needs it.
 
 ## Configuration
 

lib/rules/template-require-iframe-title.js

@@ -1,3 +1,5 @@
+'use strict';
+
 // Non-string literal AST nodes (boolean/null/undefined/number) don't represent
 // a meaningful author-provided title. Even though they would coerce to strings
 // at runtime (e.g. `true` → "true", `42` → "42"), those strings do not describe
@@ -58,8 +60,8 @@ module.exports = {
       },
     ],
     messages: {
-      // Four messageIds (missingTitle, emptyTitle, invalidTitleLiteral,
-      // duplicateTitle) for richer diagnostic detail.
+      // Five messageIds (missingTitle, emptyTitle, invalidTitleLiteral,
+      // duplicateTitleFirst, duplicateTitleOther) for richer diagnostic detail.
       missingTitle: '<iframe> elements must have a unique title property.',
       emptyTitle: '<iframe> elements must have a unique title property.',
       invalidTitleLiteral:

tests/lib/rules/template-require-iframe-title.js

@@ -251,5 +251,48 @@ hbsRuleTester.run('template-require-iframe-title', rule, {
       output: null,
       errors: [{ message: '<iframe> elements must have a unique title property.' }],
     },
+
+    // hbs parity with gjs for the other non-string mustache literals
+    // (boolean true / null / undefined / number).
+    {
+      code: '<iframe title={{true}} />',
+      output: null,
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a boolean literal, which does not describe the frame contents.',
+        },
+      ],
+    },
+    {
+      code: '<iframe title={{null}} />',
+      output: null,
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a null literal, which does not describe the frame contents.',
+        },
+      ],
+    },
+    {
+      code: '<iframe title={{undefined}} />',
+      output: null,
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a undefined literal, which does not describe the frame contents.',
+        },
+      ],
+    },
+    {
+      code: '<iframe title={{42}} />',
+      output: null,
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a number literal, which does not describe the frame contents.',
+        },
+      ],
+    },
   ],
 });