diff --git a/frontend-js/src/main/js/SessionObjectType.js b/frontend-js/src/main/js/SessionObjectType.js
index 0d7bb4b26974fa304132948ec0f4447a9a669bff..f861e193744e7fa8f5c6da3bace17c7fd895bc77 100644
--- a/frontend-js/src/main/js/SessionObjectType.js
+++ b/frontend-js/src/main/js/SessionObjectType.js
@@ -1,7 +1,8 @@
 "use strict";
 
 var SessionObjectType = {
-    SHOW_COMMENT : "SHOW_COMMENT",
+  SHOW_COMMENT : "SHOW_COMMENT",
+  ZOOM_LEVEL : "ZOOM_LEVEL",
 };
 
 module.exports = SessionObjectType;