diff --git a/lib/engine.js b/lib/engine.js
index bb61f65..4f53eaf 100644
--- a/lib/engine.js
+++ b/lib/engine.js
@@ -33,7 +33,7 @@ var inMemoryStore = {
   }
 };
 
-function isSupportedNatively() {
+var isSupportedNatively = (function() {
   try {
     if (!window.localStorage) return false;
     var key = uuid();
@@ -47,17 +47,17 @@ function isSupportedNatively() {
     // Can throw if localStorage is disabled
     return false;
   }
-}
+}());
 
 function pickStorage() {
-  if (isSupportedNatively()) {
+  if (isSupportedNatively) {
     return window.localStorage;
   }
   // fall back to in-memory
   return inMemoryStore;
 }
 
-function isReadSupportedNatively() {
+var isReadSupportedNatively = (function() {
   try {
     if (!window.localStorage) return false;
     var key = window.localStorage.key(0);
@@ -69,10 +69,10 @@ function isReadSupportedNatively() {
     // Can throw if localStorage is disabled
     return false;
   }
-}
+}());
 
 function pickReclaimStorage() {
-  if (isReadSupportedNatively()) {
+  if (isSupportedNatively || isReadSupportedNatively) {
     return window.localStorage;
   }
   // fall back to in-memory