windowExists function fix

src/mailgo.js

@@ -1,6 +1,8 @@
-// @flow
 const V = "MAILGO_VERSION";
 
+// window exists
+const windowExists = () => window && typeof window !== "undefined";
+
 // links
 const MAILTO = "mailto:";
 const TEL = "tel:";
@@ -813,9 +815,6 @@ const encodeEmail = email => btoa(email);
 // getE shorthand
 const getE = id => document.getElementById(id);
 
-// window exists
-const windowExists = () => window && typeof window !== "undefined";
-
 // get display value
 const getDisplay = id => getE(id).style.display;