From 11a46f0a743b955539c2b396a611bec0cee65068 Mon Sep 17 00:00:00 2001
From: "Davide P. Cervone" <dpvc@union.edu>
Date: Thu, 26 Feb 2026 20:55:47 -0500
Subject: [PATCH] Fix isEmpty to work with partially complete msubsup elements
 with empty bases. (mathjax/MathJax#3532)

---
 ts/core/MmlTree/MmlNode.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ts/core/MmlTree/MmlNode.ts b/ts/core/MmlTree/MmlNode.ts
index 5ee7ed3ef..217820664 100644
--- a/ts/core/MmlTree/MmlNode.ts
+++ b/ts/core/MmlTree/MmlNode.ts
@@ -546,7 +546,7 @@ export abstract class AbstractMmlNode
    */
   public get isEmpty(): boolean {
     for (const child of this.childNodes) {
-      if (!child.isEmpty) return false;
+      if (child && !child.isEmpty) return false;
     }
     return true;
   }