diff --git a/src/Nsp.php b/src/Nsp.php
index 067eac5..541c211 100644
--- a/src/Nsp.php
+++ b/src/Nsp.php
@@ -93,7 +93,7 @@ public function remove($socket)
  * @api public
  */
 
-    public function emit($ev)
+    public function emit($ev = null)
     {
         $args = func_get_args();
         if (isset(self::$events[$ev]))