diff --git a/lib/oto/commands/command.dart b/lib/oto/commands/command.dart
index dc5b4b1..b22f78a 100644
--- a/lib/oto/commands/command.dart
+++ b/lib/oto/commands/command.dart
@@ -118,7 +118,8 @@ abstract class Command {
       var map = Application.instance.commandStates;
       var param = value.replaceFirst('state.', '');
       if (map.containsKey(param)) {
-        data = map[param].toString().replaceAll('CommandState.', '');
+        var value = map[param].toString().replaceAll('CommandState.', '');
+        data = value == '' ? null : value;
       } else {
         data = null;
       }