I got error when clicking on "save and get new tracking code".

BTW, the tracking code sends a request to your server for each ajax request? That looks like a big cost to end user (duplicated number of HTTP requests a browser makes).

Error: obj is undefined this.getTrackingCode@https://demo-dot-latenlog.appspot.com/static/js/out/common.j... this.save/https://demo-dot-latenlog.appspot.com/static/js/out/common.j... $http/promise.success/https://ajax.googleapis.com/ajax/libs/angularjs/1.4.9/angula... processQueue@https://ajax.googleapis.com/ajax/libs/angularjs/1.4.9/angula... scheduleProcessQueue/https://ajax.googleapis.com/ajax/libs/angularjs/1.4.9/angula... $RootScopeProvider/this.$gethttps://ajax.googleapis.com/ajax/libs/angularjs/1.4.9/angula... $RootScopeProvider/this.$gethttps://ajax.googleapis.com/ajax/libs/angularjs/1.4.9/angula... $RootScopeProvider/this.$gethttps://ajax.googleapis.com/ajax/libs/angularjs/1.4.9/angula... done@https://ajax.googleapis.com/ajax/libs/angularjs/1.4.9/angula... completeRequest@https://ajax.googleapis.com/ajax/libs/angularjs/1.4.9/angula... requestLoaded@https://ajax.googleapis.com/ajax/libs/angularjs/1.4.9/angula... angular.js:12722:18