diff --git a/@sammo/game_logic/src/Command/index.ts b/@sammo/game_logic/src/Command/index.ts
index 590bbee..8ddeece 100644
--- a/@sammo/game_logic/src/Command/index.ts
+++ b/@sammo/game_logic/src/Command/index.ts
@@ -95,7 +95,7 @@ export abstract class BaseCommand<ArgType extends Record<string, any>>{
 
     protected abstract init(): void;
     protected initWithArg(): void {
-        if (this.arg === undefined) {
+        if (Object.keys(this.arg).length == 0) {
             return;
         }
         throw new InvalidArgument("initWithArg must be overridden if arg is not undefined");