diff --git a/shadow.js b/shadow.js
index d4d8a9e..6b5b860 100644
--- a/shadow.js
+++ b/shadow.js
@@ -50,8 +50,8 @@ export class Shadow extends HTMLElement {
   /** @private */
   _waitingList = new Set();
 
-  /** @type{HTMLTemplateElement | null } */
-  htmlData = null;
+  /** @type{HTMLTemplateElement} */
+  htmlData = createTemplate("");
 
   /** @type{JsonValue} */
   jsonData = null;