August 12, 2015 09:21 · Aug 12, 2015
diff --git a/detectBrowserLanguage.js b/detectBrowserLanguage.js
@@ -0,0 +1,24 @@
+
+// These window.navigator contain language information
+// 1. languages -> Array of preferred languages (eg ["en-US", "zh-CN", "ja-JP"]) Firefox^32, Chrome^32
+// 2. language  -> Preferred language as String (eg "en-US") Firefox^5, IE^11, Safari, 
+                   Chrome sends Browser UI language
+// 3. browserLanguage -> UI Language of IE
+// 4. userLanguage    -> Language of Windows Regional Options
+// 5. systemLanguage  -> UI Language of Windows
+var browserLanguagePropertyKeys = ['languages', 'language', 'browserLanguage', 'userLanguage', 'systemLanguage'];
+
+var availableLanguages = ['de', 'en']
+
+var browserLocale = _.chain(window.navigator)
+    .pick(browserLanguagePropertyKeys) //Get only language properties
+    .values() //Get values of the properties
+    .flatten() //flatten all arrays
+    .compact() //Remove undefined values
+    .map(function (x) {
+        return x.substr(0, 2); //Shorten strings to use two chars (en-US -> en)
+    })
+    .find(function (x) {
+        return _.contains(availableLanguages, x); //Returns first language matched in available languages
+    })
+    .value();