fix(service): use the aliased language key if available

Fixes #530

demo/l10n/en.json

@@ -0,0 +1,21 @@
+{
+"load" : {
+  "static" : {
+    "TITLE" : "How to load static files?",
+    "HEADER" : "The module can lazzy load a translations table when it's needed.",
+    "SUBHEADER" : "So, you can load only those languages, which will be used.",
+    "ONLY_EN": "only english",
+    "EN_RU": "EN and RU - EN Edition"
+  },
+  "predefined" : {
+    "TITLE" : "How to use lazzy loading without autoupload?",
+    "HEADER" : "You can predefine a default language while still using a lazzy loading.",
+    "SUBHEADER" : "This way module will not load a default language from server once more."
+  },
+  "dynamic" : {
+    "TITLE" : "How to load dynamic files?",
+    "HEADER" : "The module can lazzy load a translations table from the dynamic page.",
+    "SUBHEADER" : "It will use the \"lang\" request param passed into GET."
+  }
+}
+}

src/service/translate.js

@@ -56,7 +56,7 @@ angular.module('pascalprecht.translate').provider('$translate', ['$STORAGE_KEY',
     }
 
     if (avail.indexOf(locale) > -1) {
-      return locale;
+      return preferred;
     }
 
     if ($languageKeyAliases) {
@@ -77,6 +77,9 @@ angular.module('pascalprecht.translate').provider('$translate', ['$STORAGE_KEY',
     if (parts.length > 1 && avail.indexOf(angular.lowercase(parts[0])) > -1) {
       return parts[0];
     }
+
+    // If everything fails, just return the preferred, unchanged.
+    return preferred;
   };
 
   /**
@@ -1343,6 +1346,12 @@ angular.module('pascalprecht.translate').provider('$translate', ['$STORAGE_KEY',
 
         $rootScope.$emit('$translateChangeStart');
 
+        // Try to get the aliased language key
+        var aliasedKey = negotiateLocale(key);
+        if (aliasedKey) {
+          key = aliasedKey;
+        }
+
         // if there isn't a translation table for the language we've requested,
         // we load it asynchronously
         if (!$translationTable[key] && $loaderFactory) {

test/unit/service/translate.spec.js

@@ -269,7 +269,12 @@ describe('pascalprecht.translate', function () {
       $translateProvider
         .translations('de_DE', translationMock)
         .translations('de_DE', { 'YET_ANOTHER': 'Hallo da!' })
-        .translations('en_EN', { 'YET_ANOTHER': 'Hello there!' })
+        .translations('en', { 'YET_ANOTHER': 'Hello there!' })
+        .registerAvailableLanguageKeys(['en', 'de_DE'], {
+          'en_EN': 'en',
+          'en_US': 'en',
+          'en_GB': 'en'
+        })
         .preferredLanguage('de_DE');
     }));
 
@@ -312,6 +317,23 @@ describe('pascalprecht.translate', function () {
     });
   });
 
+  it('should respect the language aliases', function () {
+    var deferred = $q.defer(),
+        promise = deferred.promise,
+        value;
+
+    promise.then(function (translation) {
+      value = translation;
+    });
+
+    $translate.use('en_GB');
+    $translate('YET_ANOTHER').then(function (translation) {
+      deferred.resolve(translation);
+    });
+    $rootScope.$digest();
+    expect(value).toEqual('Hello there!');
+  });
+
   describe('$translate#use() with async loading', function () {
 
     var fastButRequestedSecond = 'en_US',