diff --git a/ws.js b/ws.js
index 06c3e6d..b3eb3c9 100755
--- a/ws.js
+++ b/ws.js
@@ -17,7 +17,7 @@ app.get('/', (req, res) => {
 app.ws('/', (s, req) => {
   console.error('websocket connection');
   for (var t = 0; t < 3; t++)
-    setTimeout(() => s.send('message from server'), 1000*t);
+    setTimeout(() => s.send('message from server', ()=>{}), 1000*t);
 });
 app.listen(3001, () => console.error('listening on http://localhost:3001/'));
 console.error('websocket example');