diff --git a/src/js/app/index.js b/src/js/app/index.js
index 072b7945..82e66870 100644
--- a/src/js/app/index.js
+++ b/src/js/app/index.js
@@ -1,7 +1,6 @@
 var Backbone = require('backbone');
 var EventEmitter = require('events').EventEmitter;
 var React = require('react');
-var _ = require('underscore');
 
 var assign = require('object-assign');
 var util = require('../util');
@@ -93,7 +92,8 @@ var insertAlternateLinks = function(pageId) {
 
   // The value of the hreflang attribute identifies the language (in ISO 639-1 format)
   // and optionally a region (in ISO 3166-1 Alpha 2 format) of an alternate URL
-  var altLinks = _.map(LocaleStore.getSupportedLocales(), function(langCode) {
+
+  var altLinks = LocaleStore.getSupportedLocales().map(function(langCode) {
     var url = "https://learngitbranching.js.org/?locale=" + langCode;
     return '<link rel="alternate" hreflang="'+langCode+'" href="' + url +'" />';
   });
diff --git a/src/js/stores/LocaleStore.js b/src/js/stores/LocaleStore.js
index 227bdd67..544a5af7 100644
--- a/src/js/stores/LocaleStore.js
+++ b/src/js/stores/LocaleStore.js
@@ -3,7 +3,6 @@
 var AppConstants = require('../constants/AppConstants');
 var AppDispatcher = require('../dispatcher/AppDispatcher');
 var EventEmitter = require('events').EventEmitter;
-var _ = require('underscore');
 
 var assign = require('object-assign');
 
@@ -31,7 +30,9 @@ var headerLocaleMap = {
   'pt-BR': 'pt_BR'
 };
 
-var supportedLocalesList = _.values(langLocaleMap).concat(_.values(headerLocaleMap));
+var supportedLocalesList = Object.values(langLocaleMap)
+                                 .concat(Object.values(headerLocaleMap))
+                                 .filter(function (value, index, self) { return self.indexOf(value) === index;});
 
 function _getLocaleFromHeader(langString) {
   var languages = langString.split(',');
@@ -77,7 +78,7 @@ AppConstants.StoreSubscribePrototype,
   },
 
   getSupportedLocales: function() {
-    return assign({}, supportedLocalesList);
+    return supportedLocalesList.slice();
   },
 
   dispatchToken: AppDispatcher.register(function(payload) {