Check theme class name presence on the <body>

isoos · isoos · commit 15b2a107482f · 2024-11-19T13:09:36.000+01:00
diff --git a/pkg/_pub_shared/lib/validation/html/html_validation.dart b/pkg/_pub_shared/lib/validation/html/html_validation.dart
@@ -192,6 +192,16 @@ void validateHtml(Node root) {
     throw AssertionError(
         '<$tag> tag should not have role attribute, found: ${elem.outerHtml}');
   }
+
+  // body always has one of the theme classes
+  final body = querySelectorAll('body').singleOrNull;
+  if (body != null) {
+    final classes = body.classes.toSet();
+    if (!classes.contains('light-theme') && !classes.contains('dark-theme')) {
+      throw AssertionError(
+          '<body> must contain either `light-theme` or `dark-theme`');
+    }
+  }
 }
 
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