router mixins patched

Author: vitalii

lib/RouterMixin.js

@@ -183,7 +183,11 @@ var RouterMixin = {
     }
 
     //promise between before and navigation. usefull for ajax request and other async ops
-    var promise = this.props.promise || function () {return new Promise(resolve=>{resolve()})};
+    var promise = this.props.promise || function () {
+      return new Promise(function (resolve) {
+        return resolve();
+      });
+    };
     var _this = this;
 		promise().then( function () {
 			if (navigation.onBeforeNavigation &&