fix($translate): Ensuring that languages will be set based on the ord…

…er they are requested, not the order the responses come in.

src/service/translate.js

@@ -1291,10 +1291,13 @@ angular.module('pascalprecht.translate').provider('$translate', ['$STORAGE_KEY',
         if (!$translationTable[key] && $loaderFactory) {
           $nextLang = key;
           langPromises[key] = loadAsync(key).then(function (translation) {
-            $nextLang = undefined;
             translations(translation.key, translation.table);
             deferred.resolve(translation.key);
-            useLanguage(translation.key);
+
+            if ($nextLang === key) {
+              useLanguage(translation.key);
+              $nextLang = undefined;
+            }
           }, function (key) {
             $nextLang = undefined;
             $rootScope.$emit('$translateChangeError');

test/unit/service/translate.spec.js

@@ -294,6 +294,74 @@ describe('pascalprecht.translate', function () {
     });
   });
 
+  describe('$translate#use() with async loading', function () {
+
+    var fastButRequestedSecond = 'en_US',
+        slowButRequestedFirst = 'ab_CD',
+        expectedTranslation = 'Hello World',
+        fastRequestTime = 1000;
+
+    beforeEach(module('pascalprecht.translate', function ($translateProvider, $provide) {
+
+        $translateProvider.useLoader('customLoader');
+
+        $translateProvider.preferredLanguage(slowButRequestedFirst);
+        $translateProvider.fallbackLanguage(fastButRequestedSecond);
+
+        $provide.service('customLoader', function ($q, $timeout) {
+          return function (options) {
+            var deferred = $q.defer();
+            var locale = options.key;
+
+            if (locale === fastButRequestedSecond) {
+                $timeout(function () {
+                    deferred.resolve({
+                        greeting: expectedTranslation
+                    });
+                }, fastRequestTime);
+            }
+
+            if (locale === slowButRequestedFirst) {
+
+                $timeout(function() {
+                    deferred.resolve({
+                        greeting: 'foo bar bork bork bork'
+                    });
+                }, fastRequestTime * 2);
+            }
+
+            return deferred.promise;
+        }
+      });
+    }));
+
+    var $translate;
+
+    beforeEach(inject(function ($timeout, _$translate_, $rootScope) {
+      $translate = _$translate_;
+
+      $timeout(function () {
+        $translate.use(fastButRequestedSecond);
+      }, fastRequestTime / 2);
+
+      $timeout.flush();
+      $rootScope.$digest();
+      $timeout.flush();
+    }));
+
+    it('should set the language to be the most recently requested one, not the most recently responded one', inject(function($rootScope, $q) {
+
+      var value;
+
+      $translate('greeting').then(function (translation) {
+        value = translation;
+      });
+
+      $rootScope.$digest();
+      expect(value).toEqual(expectedTranslation);
+    }));
+  });
+
   describe('$translate#storageKey()', function () {
 
     beforeEach(module('pascalprecht.translate', function ($translateProvider) {