diff --git a/app/assets/javascripts/discourse-common/addon/lib/icon-library.js b/app/assets/javascripts/discourse-common/addon/lib/icon-library.js
index 86650a1c701..7c3367415dd 100644
--- a/app/assets/javascripts/discourse-common/addon/lib/icon-library.js
+++ b/app/assets/javascripts/discourse-common/addon/lib/icon-library.js
@@ -121,7 +121,7 @@ export function setIconList(iconList) {
 }
 
 export function isExistingIconId(id) {
-  return _iconList.includes(id);
+  return _iconList?.includes(id);
 }
 
 function warnIfMissing(id) {