diff --git a/src/modules/dataset.ts b/src/modules/dataset.ts
index d9070ea..a49204b 100755
--- a/src/modules/dataset.ts
+++ b/src/modules/dataset.ts
@@ -19,8 +19,10 @@ function updateDataset(oldVnode: VNode, vnode: VNode): void {
 
   for (key in oldDataset) {
     if (!dataset[key]) {
-      if (d && d[key]) {
-        delete d[key];
+      if (d) {
+        if (key in d) {
+          delete d[key];
+        }
       } else {
         elm.removeAttribute('data-' + key.replace(CAPS_REGEX, '-$&').toLowerCase());
       }