added suport for isomorphic rendering

Author: dinodsaurus

Diff for: lib/helpers/ariaAppHider.js

@@ -1,4 +1,7 @@
-var _element = document.body;
+var _element = "";
+if(typeof window !== 'undefined'){
+  _element = document.body;
+}
 
 function setElement(element) {
   if (typeof element === 'string') {
@@ -39,4 +42,3 @@ exports.setElement = setElement;
 exports.show = show;
 exports.hide = hide;
 exports.resetForTesting = resetForTesting;
-