diff --git a/lib/6to5/types/alias-keys.json b/lib/6to5/types/alias-keys.json
index 4a476ff0b5..076ad3e898 100644
--- a/lib/6to5/types/alias-keys.json
+++ b/lib/6to5/types/alias-keys.json
@@ -21,5 +21,7 @@
   "ForStatement":   ["For"],
 
   "ObjectPattern": ["Pattern"],
-  "ArrayPattern":  ["Pattern"]
+  "ArrayPattern":  ["Pattern"],
+
+  "Property": ["UserWhitespacable"]
 }