diff --git a/src/lib/utils.js b/src/lib/utils.js
index 8ad4765..a050f2e 100644
--- a/src/lib/utils.js
+++ b/src/lib/utils.js
@@ -84,6 +84,10 @@ const getPluralType = (type) =>{
   // is not generated in the lookup. this is a
   // kludge around that. (specifically availabilitySummary)
   plural = teamsnap.getPluralType(type) || (function() {
+    if (type === undefined){
+      return type
+    }
+
     switch (type.slice(-1)) {
       case 'y':
         return type.slice(0, -1) + 'ies';