diff --git a/src/cxtmenu.js b/src/cxtmenu.js
index 89dc0dc1..15bacb67 100644
--- a/src/cxtmenu.js
+++ b/src/cxtmenu.js
@@ -373,7 +373,7 @@ let cxtmenu = function(params){
 
         if( typeof options.commands === 'function' ){
           const res = options.commands(target);
-          if( res instanceof Promise ){
+          if( res.then ){
             res.then(_commands => {
               commands = _commands;
               openMenu();