[internals] added isIOS / isAndroid utils

lib/utils/index.js

@@ -1,9 +1,8 @@
-import {Platform} from 'react-native';
+// @flow
+import { Platform } from 'react-native';
 
 // todo cleanup unused utilities from legacy code
-/**
- * @flow
- */
+
 // modeled after base64 web-safe chars, but ordered by ASCII
 const PUSH_CHARS = '-0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz';
 const hasOwnProperty = Object.hasOwnProperty;
@@ -88,10 +87,18 @@ export function isString(value): Boolean {
   return typeof value === 'string';
 }
 
+/**
+ * Returns true if on ios
+ * @returns {boolean}
+ */
 export function isIOS() {
   return Platform.OS === 'ios';
 }
 
+/**
+ * Returns true if on android
+ * @returns {boolean}
+ */
 export function isAndroid() {
   return Platform.OS === 'android';
 }