translate.js

/**
 * @ngdoc object
 * @name pascalprecht.translate.$translateProvider
 * @description
 *
 * $translateProvider allows developers to register translation-tables, asynchronous loaders
 * and similar to configure translation behavior directly inside of a module.
 *
 */
angular.module('pascalprecht.translate')
  .constant('pascalprechtTranslateOverrider', {})
  .provider('$translate', $translate);

function $translate($STORAGE_KEY, $windowProvider, $translateSanitizationProvider, pascalprechtTranslateOverrider) {

  'use strict';

  var $translationTable = {},
    $preferredLanguage,
    $availableLanguageKeys = [],
    $languageKeyAliases,
    $fallbackLanguage,
    $fallbackWasString,
    $uses,
    $nextLang,
    $storageFactory,
    $storageKey = $STORAGE_KEY,
    $storagePrefix,
    $missingTranslationHandlerFactory,
    $interpolationFactory,
    $interpolatorFactories = [],
    $loaderFactory,
    $cloakClassName = 'translate-cloak',
    $loaderOptions,
    $notFoundIndicatorLeft,
    $notFoundIndicatorRight,
    $postCompilingEnabled = false,
    $forceAsyncReloadEnabled = false,
    $nestedObjectDelimeter = '.',
    $isReady = false,
    $keepContent = false,
    loaderCache,
    directivePriority = 0,
    statefulFilter = true,
    postProcessFn,
    uniformLanguageTagResolver = 'default',
    languageTagResolver = {
      'default' : function (tag) {
        return (tag || '').split('-').join('_');
      },
      java : function (tag) {
        var temp = (tag || '').split('-').join('_');
        var parts = temp.split('_');
        return parts.length > 1 ? (parts[0].toLowerCase() + '_' + parts[1].toUpperCase()) : temp;
      },
      bcp47 : function (tag) {
        var temp = (tag || '').split('_').join('-');
        var parts = temp.split('-');
        return parts.length > 1 ? (parts[0].toLowerCase() + '-' + parts[1].toUpperCase()) : temp;
      },
      'iso639-1' : function (tag) {
        var temp = (tag || '').split('_').join('-');
        var parts = temp.split('-');
        return parts[0].toLowerCase();
      }
    };

  var version = 'x.y.z';

  // tries to determine the browsers language
  var getFirstBrowserLanguage = function () {

    // internal purpose only
    if (angular.isFunction(pascalprechtTranslateOverrider.getLocale)) {
      return pascalprechtTranslateOverrider.getLocale();
    }

    var nav = $windowProvider.$get().navigator,
      browserLanguagePropertyKeys = ['language', 'browserLanguage', 'systemLanguage', 'userLanguage'],
      i,
      language;

    // support for HTML 5.1 "navigator.languages"
    if (angular.isArray(nav.languages)) {
      for (i = 0; i < nav.languages.length; i++) {
        language = nav.languages[i];
        if (language && language.length) {
          return language;
        }
      }
    }

    // support for other well known properties in browsers
    for (i = 0; i < browserLanguagePropertyKeys.length; i++) {
      language = nav[browserLanguagePropertyKeys[i]];
      if (language && language.length) {
        return language;
      }
    }

    return null;
  };
  getFirstBrowserLanguage.displayName = 'angular-translate/service: getFirstBrowserLanguage';

  // tries to determine the browsers locale
  var getLocale = function () {
    var locale = getFirstBrowserLanguage() || '';
    if (languageTagResolver[uniformLanguageTagResolver]) {
      locale = languageTagResolver[uniformLanguageTagResolver](locale);
    }
    return locale;
  };
  getLocale.displayName = 'angular-translate/service: getLocale';

  /**
   * @name indexOf
   * @private
   *
   * @description
   * indexOf polyfill. Kinda sorta.
   *
   * @param {array} array Array to search in.
   * @param {string} searchElement Element to search for.
   *
   * @returns {int} Index of search element.
   */
  var indexOf = function (array, searchElement) {
    for (var i = 0, len = array.length; i < len; i++) {
      if (array[i] === searchElement) {
        return i;
      }
    }
    return -1;
  };

  /**
   * @name trim
   * @private
   *
   * @description
   * trim polyfill
   *
   * @returns {string} The string stripped of whitespace from both ends
   */
  var trim = function () {
    return this.toString().replace(/^\s+|\s+$/g, '');
  };

  /**
   * @name lowercase
   * @private
   *
   * @description
   * Return the lowercase string only if the type is string
   *
   * @returns {string} The string all in lowercase
   */
  var lowercase = function (string) {
    return angular.isString(string) ? string.toLowerCase() : string;
  };

  var negotiateLocale = function (preferred) {
    if (!preferred) {
      return;
    }

    var avail = [],
      locale = lowercase(preferred),
      i = 0,
      n = $availableLanguageKeys.length;

    for (; i < n; i++) {
      avail.push(lowercase($availableLanguageKeys[i]));
    }

    // Check for an exact match in our list of available keys
    i = indexOf(avail, locale);
    if (i > -1) {
      return $availableLanguageKeys[i];
    }

    if ($languageKeyAliases) {
      var alias;
      for (var langKeyAlias in $languageKeyAliases) {
        if ($languageKeyAliases.hasOwnProperty(langKeyAlias)) {
          var hasWildcardKey = false;
          var hasExactKey = Object.prototype.hasOwnProperty.call($languageKeyAliases, langKeyAlias) &&
            lowercase(langKeyAlias) === lowercase(preferred);

          if (langKeyAlias.slice(-1) === '*') {
            hasWildcardKey = lowercase(langKeyAlias.slice(0, -1)) === lowercase(preferred.slice(0, langKeyAlias.length - 1));
          }
          if (hasExactKey || hasWildcardKey) {
            alias = $languageKeyAliases[langKeyAlias];
            if (indexOf(avail, lowercase(alias)) > -1) {
              return alias;
            }
          }
        }
      }
    }

    // Check for a language code without region
    var parts = preferred.split('_');

    if (parts.length > 1 && indexOf(avail, lowercase(parts[0])) > -1) {
      return parts[0];
    }

    // If everything fails, return undefined.
    return;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#translations
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Registers a new translation table for specific language key.
   *
   * To register a translation table for specific language, pass a defined language
   * key as first parameter.
   *
   * <pre>
   *  // register translation table for language: 'de_DE'
   *  $translateProvider.translations('de_DE', {
   *    'GREETING': 'Hallo Welt!'
   *  });
   *
   *  // register another one
   *  $translateProvider.translations('en_US', {
   *    'GREETING': 'Hello world!'
   *  });
   * </pre>
   *
   * When registering multiple translation tables for for the same language key,
   * the actual translation table gets extended. This allows you to define module
   * specific translation which only get added, once a specific module is loaded in
   * your app.
   *
   * Invoking this method with no arguments returns the translation table which was
   * registered with no language key. Invoking it with a language key returns the
   * related translation table.
   *
   * @param {string} langKey A language key.
   * @param {object} translationTable A plain old JavaScript object that represents a translation table.
   *
   */
  var translations = function (langKey, translationTable) {

    if (!langKey && !translationTable) {
      return $translationTable;
    }

    if (langKey && !translationTable) {
      if (angular.isString(langKey)) {
        return $translationTable[langKey];
      }
    } else {
      if (!angular.isObject($translationTable[langKey])) {
        $translationTable[langKey] = {};
      }
      angular.extend($translationTable[langKey], flatObject(translationTable));
    }
    return this;
  };

  this.translations = translations;

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#cloakClassName
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   *
   * Let's you change the class name for `translate-cloak` directive.
   * Default class name is `translate-cloak`.
   *
   * @param {string} name translate-cloak class name
   */
  this.cloakClassName = function (name) {
    if (!name) {
      return $cloakClassName;
    }
    $cloakClassName = name;
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#nestedObjectDelimeter
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   *
   * Let's you change the delimiter for namespaced translations.
   * Default delimiter is `.`.
   *
   * @param {string} delimiter namespace separator
   */
  this.nestedObjectDelimeter = function (delimiter) {
    if (!delimiter) {
      return $nestedObjectDelimeter;
    }
    $nestedObjectDelimeter = delimiter;
    return this;
  };

  /**
   * @name flatObject
   * @private
   *
   * @description
   * Flats an object. This function is used to flatten given translation data with
   * namespaces, so they are later accessible via dot notation.
   */
  var flatObject = function (data, path, result, prevKey) {
    var key, keyWithPath, keyWithShortPath, val;

    if (!path) {
      path = [];
    }
    if (!result) {
      result = {};
    }
    for (key in data) {
      if (!Object.prototype.hasOwnProperty.call(data, key)) {
        continue;
      }
      val = data[key];
      if (angular.isObject(val)) {
        flatObject(val, path.concat(key), result, key);
      } else {
        keyWithPath = path.length ? ('' + path.join($nestedObjectDelimeter) + $nestedObjectDelimeter + key) : key;
        if (path.length && key === prevKey) {
          // Create shortcut path (foo.bar == foo.bar.bar)
          keyWithShortPath = '' + path.join($nestedObjectDelimeter);
          // Link it to original path
          result[keyWithShortPath] = '@:' + keyWithPath;
        }
        result[keyWithPath] = val;
      }
    }
    return result;
  };
  flatObject.displayName = 'flatObject';

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#addInterpolation
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Adds interpolation services to angular-translate, so it can manage them.
   *
   * @param {object} factory Interpolation service factory
   */
  this.addInterpolation = function (factory) {
    $interpolatorFactories.push(factory);
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useMessageFormatInterpolation
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate to use interpolation functionality of messageformat.js.
   * This is useful when having high level pluralization and gender selection.
   */
  this.useMessageFormatInterpolation = function () {
    return this.useInterpolation('$translateMessageFormatInterpolation');
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useInterpolation
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate which interpolation style to use as default, application-wide.
   * Simply pass a factory/service name. The interpolation service has to implement
   * the correct interface.
   *
   * @param {string} factory Interpolation service name.
   */
  this.useInterpolation = function (factory) {
    $interpolationFactory = factory;
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useSanitizeStrategy
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Simply sets a sanitation strategy type.
   *
   * @param {string} value Strategy type.
   */
  this.useSanitizeValueStrategy = function (value) {
    $translateSanitizationProvider.useStrategy(value);
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#preferredLanguage
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells the module which of the registered translation tables to use for translation
   * at initial startup by passing a language key. Similar to `$translateProvider#use`
   * only that it says which language to **prefer**.
   * It is recommended to call this after {@link pascalprecht.translate.$translate#fallbackLanguage fallbackLanguage()}.
   *
   * @param {string} langKey A language key.
   */
  this.preferredLanguage = function (langKey) {
    if (langKey) {
      setupPreferredLanguage(langKey);
      return this;
    }
    return $preferredLanguage;
  };
  var setupPreferredLanguage = function (langKey) {
    if (langKey) {
      $preferredLanguage = langKey;
    }
    return $preferredLanguage;
  };
  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#translationNotFoundIndicator
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Sets an indicator which is used when a translation isn't found. E.g. when
   * setting the indicator as 'X' and one tries to translate a translation id
   * called `NOT_FOUND`, this will result in `X NOT_FOUND X`.
   *
   * Internally this methods sets a left indicator and a right indicator using
   * `$translateProvider.translationNotFoundIndicatorLeft()` and
   * `$translateProvider.translationNotFoundIndicatorRight()`.
   *
   * **Note**: These methods automatically add a whitespace between the indicators
   * and the translation id.
   *
   * @param {string} indicator An indicator, could be any string.
   */
  this.translationNotFoundIndicator = function (indicator) {
    this.translationNotFoundIndicatorLeft(indicator);
    this.translationNotFoundIndicatorRight(indicator);
    return this;
  };

  /**
   * ngdoc function
   * @name pascalprecht.translate.$translateProvider#translationNotFoundIndicatorLeft
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Sets an indicator which is used when a translation isn't found left to the
   * translation id.
   *
   * @param {string} indicator An indicator.
   */
  this.translationNotFoundIndicatorLeft = function (indicator) {
    if (!indicator) {
      return $notFoundIndicatorLeft;
    }
    $notFoundIndicatorLeft = indicator;
    return this;
  };

  /**
   * ngdoc function
   * @name pascalprecht.translate.$translateProvider#translationNotFoundIndicatorLeft
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Sets an indicator which is used when a translation isn't found right to the
   * translation id.
   *
   * @param {string} indicator An indicator.
   */
  this.translationNotFoundIndicatorRight = function (indicator) {
    if (!indicator) {
      return $notFoundIndicatorRight;
    }
    $notFoundIndicatorRight = indicator;
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#fallbackLanguage
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells the module which of the registered translation tables to use when missing translations
   * at initial startup by passing a language key. Similar to `$translateProvider#use`
   * only that it says which language to **fallback**.
   *
   * @param {string||array} langKey A language key.
   *
   */
  this.fallbackLanguage = function (langKey) {
    fallbackStack(langKey);
    return this;
  };

  var fallbackStack = function (langKey) {
    if (langKey) {
      if (angular.isString(langKey)) {
        $fallbackWasString = true;
        $fallbackLanguage = [langKey];
      } else if (angular.isArray(langKey)) {
        $fallbackWasString = false;
        $fallbackLanguage = langKey;
      }
      if (angular.isString($preferredLanguage) && indexOf($fallbackLanguage, $preferredLanguage) < 0) {
        $fallbackLanguage.push($preferredLanguage);
      }

      return this;
    } else {
      if ($fallbackWasString) {
        return $fallbackLanguage[0];
      } else {
        return $fallbackLanguage;
      }
    }
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#use
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Set which translation table to use for translation by given language key. When
   * trying to 'use' a language which isn't provided, it'll throw an error.
   *
   * You actually don't have to use this method since `$translateProvider#preferredLanguage`
   * does the job too.
   *
   * @param {string} langKey A language key.
   */
  this.use = function (langKey) {
    if (langKey) {
      if (!$translationTable[langKey] && (!$loaderFactory)) {
        // only throw an error, when not loading translation data asynchronously
        throw new Error('$translateProvider couldn\'t find translationTable for langKey: \'' + langKey + '\'');
      }
      $uses = langKey;
      return this;
    }
    return $uses;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#resolveClientLocale
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * This returns the current browser/client's language key. The result is processed with the configured uniform tag resolver.
   *
   * @returns {string} the current client/browser language key
   */
  this.resolveClientLocale = function () {
    return getLocale();
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#storageKey
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells the module which key must represent the choosed language by a user in the storage.
   *
   * @param {string} key A key for the storage.
   */
  var storageKey = function (key) {
    if (!key) {
      if ($storagePrefix) {
        return $storagePrefix + $storageKey;
      }
      return $storageKey;
    }
    $storageKey = key;
    return this;
  };

  this.storageKey = storageKey;

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useUrlLoader
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate to use `$translateUrlLoader` extension service as loader.
   *
   * @param {string} url Url
   * @param {Object=} options Optional configuration object
   */
  this.useUrlLoader = function (url, options) {
    return this.useLoader('$translateUrlLoader', angular.extend({url : url}, options));
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useStaticFilesLoader
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate to use `$translateStaticFilesLoader` extension service as loader.
   *
   * @param {Object=} options Optional configuration object
   */
  this.useStaticFilesLoader = function (options) {
    return this.useLoader('$translateStaticFilesLoader', options);
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useLoader
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate to use any other service as loader.
   *
   * @param {string} loaderFactory Factory name to use
   * @param {Object=} options Optional configuration object
   */
  this.useLoader = function (loaderFactory, options) {
    $loaderFactory = loaderFactory;
    $loaderOptions = options || {};
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useLocalStorage
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate to use `$translateLocalStorage` service as storage layer.
   *
   */
  this.useLocalStorage = function () {
    return this.useStorage('$translateLocalStorage');
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useCookieStorage
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate to use `$translateCookieStorage` service as storage layer.
   */
  this.useCookieStorage = function () {
    return this.useStorage('$translateCookieStorage');
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useStorage
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate to use custom service as storage layer.
   */
  this.useStorage = function (storageFactory) {
    $storageFactory = storageFactory;
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#storagePrefix
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Sets prefix for storage key.
   *
   * @param {string} prefix Storage key prefix
   */
  this.storagePrefix = function (prefix) {
    if (!prefix) {
      return prefix;
    }
    $storagePrefix = prefix;
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useMissingTranslationHandlerLog
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate to use built-in log handler when trying to translate
   * a translation Id which doesn't exist.
   *
   * This is actually a shortcut method for `useMissingTranslationHandler()`.
   *
   */
  this.useMissingTranslationHandlerLog = function () {
    return this.useMissingTranslationHandler('$translateMissingTranslationHandlerLog');
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useMissingTranslationHandler
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Expects a factory name which later gets instantiated with `$injector`.
   * This method can be used to tell angular-translate to use a custom
   * missingTranslationHandler. Just build a factory which returns a function
   * and expects a translation id as argument.
   *
   * Example:
   * <pre>
   *  app.config(function ($translateProvider) {
   *    $translateProvider.useMissingTranslationHandler('customHandler');
   *  });
   *
   *  app.factory('customHandler', function (dep1, dep2) {
   *    return function (translationId) {
   *      // something with translationId and dep1 and dep2
   *    };
   *  });
   * </pre>
   *
   * @param {string} factory Factory name
   */
  this.useMissingTranslationHandler = function (factory) {
    $missingTranslationHandlerFactory = factory;
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#usePostCompiling
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * If post compiling is enabled, all translated values will be processed
   * again with AngularJS' $compile.
   *
   * Example:
   * <pre>
   *  app.config(function ($translateProvider) {
   *    $translateProvider.usePostCompiling(true);
   *  });
   * </pre>
   *
   * @param {string} factory Factory name
   */
  this.usePostCompiling = function (value) {
    $postCompilingEnabled = !(!value);
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#forceAsyncReload
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * If force async reload is enabled, async loader will always be called
   * even if $translationTable already contains the language key, adding
   * possible new entries to the $translationTable.
   *
   * Example:
   * <pre>
   *  app.config(function ($translateProvider) {
   *    $translateProvider.forceAsyncReload(true);
   *  });
   * </pre>
   *
   * @param {boolean} value - valid values are true or false
   */
  this.forceAsyncReload = function (value) {
    $forceAsyncReloadEnabled = !(!value);
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#uniformLanguageTag
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate which language tag should be used as a result when determining
   * the current browser language.
   *
   * This setting must be set before invoking {@link pascalprecht.translate.$translateProvider#methods_determinePreferredLanguage determinePreferredLanguage()}.
   *
   * <pre>
   * $translateProvider
   *   .uniformLanguageTag('bcp47')
   *   .determinePreferredLanguage()
   * </pre>
   *
   * The resolver currently supports:
   * * default
   *     (traditionally: hyphens will be converted into underscores, i.e. en-US => en_US)
   *     en-US => en_US
   *     en_US => en_US
   *     en-us => en_us
   * * java
   *     like default, but the second part will be always in uppercase
   *     en-US => en_US
   *     en_US => en_US
   *     en-us => en_US
   * * BCP 47 (RFC 4646 & 4647)
   *     en-US => en-US
   *     en_US => en-US
   *     en-us => en-US
   *
   * See also:
   * * http://en.wikipedia.org/wiki/IETF_language_tag
   * * http://www.w3.org/International/core/langtags/
   * * http://tools.ietf.org/html/bcp47
   *
   * @param {string|object} options - options (or standard)
   * @param {string} options.standard - valid values are 'default', 'bcp47', 'java'
   */
  this.uniformLanguageTag = function (options) {

    if (!options) {
      options = {};
    } else if (angular.isString(options)) {
      options = {
        standard : options
      };
    }

    uniformLanguageTagResolver = options.standard;

    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#determinePreferredLanguage
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Tells angular-translate to try to determine on its own which language key
   * to set as preferred language. When `fn` is given, angular-translate uses it
   * to determine a language key, otherwise it uses the built-in `getLocale()`
   * method.
   *
   * The `getLocale()` returns a language key in the format `[lang]_[country]` or
   * `[lang]` depending on what the browser provides.
   *
   * Use this method at your own risk, since not all browsers return a valid
   * locale (see {@link pascalprecht.translate.$translateProvider#methods_uniformLanguageTag uniformLanguageTag()}).
   *
   * @param {Function=} fn Function to determine a browser's locale
   */
  this.determinePreferredLanguage = function (fn) {

    var locale = (fn && angular.isFunction(fn)) ? fn() : getLocale();

    if (!$availableLanguageKeys.length) {
      $preferredLanguage = locale;
    } else {
      $preferredLanguage = negotiateLocale(locale) || locale;
    }

    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#registerAvailableLanguageKeys
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Registers a set of language keys the app will work with. Use this method in
   * combination with
   * {@link pascalprecht.translate.$translateProvider#determinePreferredLanguage determinePreferredLanguage}.
   * When available languages keys are registered, angular-translate
   * tries to find the best fitting language key depending on the browsers locale,
   * considering your language key convention.
   *
   * @param {object} languageKeys Array of language keys the your app will use
   * @param {object=} aliases Alias map.
   */
  this.registerAvailableLanguageKeys = function (languageKeys, aliases) {
    if (languageKeys) {
      $availableLanguageKeys = languageKeys;
      if (aliases) {
        $languageKeyAliases = aliases;
      }
      return this;
    }
    return $availableLanguageKeys;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#useLoaderCache
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Registers a cache for internal $http based loaders.
   * {@link pascalprecht.translate.$translationCache $translationCache}.
   * When false the cache will be disabled (default). When true or undefined
   * the cache will be a default (see $cacheFactory). When an object it will
   * be treat as a cache object itself: the usage is $http({cache: cache})
   *
   * @param {object} cache boolean, string or cache-object
   */
  this.useLoaderCache = function (cache) {
    if (cache === false) {
      // disable cache
      loaderCache = undefined;
    } else if (cache === true) {
      // enable cache using AJS defaults
      loaderCache = true;
    } else if (typeof(cache) === 'undefined') {
      // enable cache using default
      loaderCache = '$translationCache';
    } else if (cache) {
      // enable cache using given one (see $cacheFactory)
      loaderCache = cache;
    }
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#directivePriority
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Sets the default priority of the translate directive. The standard value is `0`.
   * Calling this function without an argument will return the current value.
   *
   * @param {number} priority for the translate-directive
   */
  this.directivePriority = function (priority) {
    if (priority === undefined) {
      // getter
      return directivePriority;
    } else {
      // setter with chaining
      directivePriority = priority;
      return this;
    }
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#statefulFilter
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * Since AngularJS 1.3, filters which are not stateless (depending at the scope)
   * have to explicit define this behavior.
   * Sets whether the translate filter should be stateful or stateless. The standard value is `true`
   * meaning being stateful.
   * Calling this function without an argument will return the current value.
   *
   * @param {boolean} state - defines the state of the filter
   */
  this.statefulFilter = function (state) {
    if (state === undefined) {
      // getter
      return statefulFilter;
    } else {
      // setter with chaining
      statefulFilter = state;
      return this;
    }
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#postProcess
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * The post processor will be intercept right after the translation result. It can modify the result.
   *
   * @param {object} fn Function or service name (string) to be called after the translation value has been set / resolved. The function itself will enrich every value being processed and then continue the normal resolver process
   */
  this.postProcess = function (fn) {
    if (fn) {
      postProcessFn = fn;
    } else {
      postProcessFn = undefined;
    }
    return this;
  };

  /**
   * @ngdoc function
   * @name pascalprecht.translate.$translateProvider#keepContent
   * @methodOf pascalprecht.translate.$translateProvider
   *
   * @description
   * If keepContent is set to true than translate directive will always use innerHTML
   * as a default translation
   *
   * Example:
   * <pre>
   *  app.config(function ($translateProvider) {
   *    $translateProvider.keepContent(true);
   *  });
   * </pre>
   *
   * @param {boolean} value - valid values are true or false
   */
  this.keepContent = function (value) {
    $keepContent = !(!value);
    return this;
  };

  /**
   * @ngdoc object
   * @name pascalprecht.translate.$translate
   * @requires $interpolate
   * @requires $log
   * @requires $rootScope
   * @requires $q
   *
   * @description
   * The `$translate` service is the actual core of angular-translate. It expects a translation id
   * and optional interpolate parameters to translate contents.
   *
   * <pre>
   *  $translate('HEADLINE_TEXT').then(function (translation) {
   *    $scope.translatedText = translation;
   *  });
   * </pre>
   *
   * @param {string|array} translationId A token which represents a translation id
   *                                     This can be optionally an array of translation ids which
   *                                     results that the function returns an object where each key
   *                                     is the translation id and the value the translation.
   * @param {object=} [interpolateParams={}] An object hash for dynamic values
   * @param {string=} [interpolationId=undefined] The id of the interpolation to use (use default unless set via useInterpolation())
   * @param {string=} [defaultTranslationText=undefined] the optional default translation text that is written as
   *                                        as default text in case it is not found in any configured language
   * @param {string=} [forceLanguage=false] A language to be used instead of the current language
   * @param {string=} [sanitizeStrategy=undefined] force sanitize strategy for this call instead of using the configured one (use default unless set)
   * @returns {object} promise
   */
  this.$get = function ($log, $injector, $rootScope, $q) {

    var Storage,
      defaultInterpolator = $injector.get($interpolationFactory || '$translateDefaultInterpolation'),
      pendingLoader = false,
      interpolatorHashMap = {},
      langPromises = {},
      fallbackIndex,
      startFallbackIteration;

    var $translate = function (translationId, interpolateParams, interpolationId, defaultTranslationText, forceLanguage, sanitizeStrategy) {
      if (!$uses && $preferredLanguage) {
        $uses = $preferredLanguage;
      }
      var uses = (forceLanguage && forceLanguage !== $uses) ? // we don't want to re-negotiate $uses
        (negotiateLocale(forceLanguage) || forceLanguage) : $uses;

      // Check forceLanguage is present
      if (forceLanguage) {
        loadTranslationsIfMissing(forceLanguage);
      }

      // Duck detection: If the first argument is an array, a bunch of translations was requested.
      // The result is an object.
      if (angular.isArray(translationId)) {
        // Inspired by Q.allSettled by Kris Kowal
        // https://github.com/kriskowal/q/blob/b0fa72980717dc202ffc3cbf03b936e10ebbb9d7/q.js#L1553-1563
        // This transforms all promises regardless resolved or rejected
        var translateAll = function (translationIds) {
          var results = {}; // storing the actual results
          var promises = []; // promises to wait for
          // Wraps the promise a) being always resolved and b) storing the link id->value
          var translate = function (translationId) {
            var deferred = $q.defer();
            var regardless = function (value) {
              results[translationId] = value;
              deferred.resolve([translationId, value]);
            };
            // we don't care whether the promise was resolved or rejected; just store the values
            $translate(translationId, interpolateParams, interpolationId, defaultTranslationText, forceLanguage, sanitizeStrategy).then(regardless, regardless);
            return deferred.promise;
          };
          for (var i = 0, c = translationIds.length; i < c; i++) {
            promises.push(translate(translationIds[i]));
          }
          // wait for all (including storing to results)
          return $q.all(promises).then(function () {
            // return the results
            return results;
          });
        };
        return translateAll(translationId);
      }

      var deferred = $q.defer();

      // trim off any whitespace
      if (translationId) {
        translationId = trim.apply(translationId);
      }

      var promiseToWaitFor = (function () {
        var promise = langPromises[uses] || langPromises[$preferredLanguage];

        fallbackIndex = 0;

        if ($storageFactory && !promise) {
          // looks like there's no pending promise for $preferredLanguage or
          // $uses. Maybe there's one pending for a language that comes from
          // storage.
          var langKey = Storage.get($storageKey);
          promise = langPromises[langKey];

          if ($fallbackLanguage && $fallbackLanguage.length) {
            var index = indexOf($fallbackLanguage, langKey);
            // maybe the language from storage is also defined as fallback language
            // we increase the fallback language index to not search in that language
            // as fallback, since it's probably the first used language
            // in that case the index starts after the first element
            fallbackIndex = (index === 0) ? 1 : 0;

            // but we can make sure to ALWAYS fallback to preferred language at least
            if (indexOf($fallbackLanguage, $preferredLanguage) < 0) {
              $fallbackLanguage.push($preferredLanguage);
            }
          }
        }
        return promise;
      }());

      if (!promiseToWaitFor) {
        // no promise to wait for? okay. Then there's no loader registered
        // nor is a one pending for language that comes from storage.
        // We can just translate.
        determineTranslation(translationId, interpolateParams, interpolationId, defaultTranslationText, uses, sanitizeStrategy).then(deferred.resolve, deferred.reject);
      } else {
        var promiseResolved = function () {
          // $uses may have changed while waiting
          if (!forceLanguage) {
            uses = $uses;
          }
          determineTranslation(translationId, interpolateParams, interpolationId, defaultTranslationText, uses, sanitizeStrategy).then(deferred.resolve, deferred.reject);
        };
        promiseResolved.displayName = 'promiseResolved';

        promiseToWaitFor['finally'](promiseResolved)['catch'](angular.noop); // we don't care about errors here, already handled
      }
      return deferred.promise;
    };

    /**
     * @name applyNotFoundIndicators
     * @private
     *
     * @description
     * Applies not fount indicators to given translation id, if needed.
     * This function gets only executed, if a translation id doesn't exist,
     * which is why a translation id is expected as argument.
     *
     * @param {string} translationId Translation id.
     * @returns {string} Same as given translation id but applied with not found
     * indicators.
     */
    var applyNotFoundIndicators = function (translationId) {
      // applying notFoundIndicators
      if ($notFoundIndicatorLeft) {
        translationId = [$notFoundIndicatorLeft, translationId].join(' ');
      }
      if ($notFoundIndicatorRight) {
        translationId = [translationId, $notFoundIndicatorRight].join(' ');
      }
      return translationId;
    };

    /**
     * @name useLanguage
     * @private
     *
     * @description
     * Makes actual use of a language by setting a given language key as used
     * language and informs registered interpolators to also use the given
     * key as locale.
     *
     * @param {string} key Locale key.
     */
    var useLanguage = function (key) {
      $uses = key;

      // make sure to store new language key before triggering success event
      if ($storageFactory) {
        Storage.put($translate.storageKey(), $uses);
      }

      $rootScope.$emit('$translateChangeSuccess', {language : key});

      // inform default interpolator
      defaultInterpolator.setLocale($uses);

      var eachInterpolator = function (interpolator, id) {
        interpolatorHashMap[id].setLocale($uses);
      };
      eachInterpolator.displayName = 'eachInterpolatorLocaleSetter';

      // inform all others too!
      angular.forEach(interpolatorHashMap, eachInterpolator);
      $rootScope.$emit('$translateChangeEnd', {language : key});
    };

    /**
     * @name loadAsync
     * @private
     *
     * @description
     * Kicks off registered async loader using `$injector` and applies existing
     * loader options. When resolved, it updates translation tables accordingly
     * or rejects with given language key.
     *
     * @param {string} key Language key.
     * @return {Promise} A promise.
     */
    var loadAsync = function (key) {
      if (!key) {
        throw 'No language key specified for loading.';
      }

      var deferred = $q.defer();

      $rootScope.$emit('$translateLoadingStart', {language : key});
      pendingLoader = true;

      var cache = loaderCache;
      if (typeof(cache) === 'string') {
        // getting on-demand instance of loader
        cache = $injector.get(cache);
      }

      var loaderOptions = angular.extend({}, $loaderOptions, {
        key : key,
        $http : angular.extend({}, {
          cache : cache
        }, $loaderOptions.$http)
      });

      var onLoaderSuccess = function (data) {
        var translationTable = {};
        $rootScope.$emit('$translateLoadingSuccess', {language : key});

        if (angular.isArray(data)) {
          angular.forEach(data, function (table) {
            angular.extend(translationTable, flatObject(table));
          });
        } else {
          angular.extend(translationTable, flatObject(data));
        }
        pendingLoader = false;
        deferred.resolve({
          key : key,
          table : translationTable
        });
        $rootScope.$emit('$translateLoadingEnd', {language : key});
      };
      onLoaderSuccess.displayName = 'onLoaderSuccess';

      var onLoaderError = function (key) {
        $rootScope.$emit('$translateLoadingError', {language : key});
        deferred.reject(key);
        $rootScope.$emit('$translateLoadingEnd', {language : key});
      };
      onLoaderError.displayName = 'onLoaderError';

      $injector.get($loaderFactory)(loaderOptions)
        .then(onLoaderSuccess, onLoaderError);

      return deferred.promise;
    };

    if ($storageFactory) {
      Storage = $injector.get($storageFactory);

      if (!Storage.get || !Storage.put) {
        throw new Error('Couldn\'t use storage \'' + $storageFactory + '\', missing get() or put() method!');
      }
    }

    // if we have additional interpolations that were added via
    // $translateProvider.addInterpolation(), we have to map'em
    if ($interpolatorFactories.length) {
      var eachInterpolationFactory = function (interpolatorFactory) {
        var interpolator = $injector.get(interpolatorFactory);
        // setting initial locale for each interpolation service
        interpolator.setLocale($preferredLanguage || $uses);
        // make'em recognizable through id
        interpolatorHashMap[interpolator.getInterpolationIdentifier()] = interpolator;
      };
      eachInterpolationFactory.displayName = 'interpolationFactoryAdder';

      angular.forEach($interpolatorFactories, eachInterpolationFactory);
    }

    /**
     * @name getTranslationTable
     * @private
     *
     * @description
     * Returns a promise that resolves to the translation table
     * or is rejected if an error occurred.
     *
     * @param langKey
     * @returns {Q.promise}
     */
    var getTranslationTable = function (langKey) {
      var deferred = $q.defer();
      if (Object.prototype.hasOwnProperty.call($translationTable, langKey)) {
        deferred.resolve($translationTable[langKey]);
      } else if (langPromises[langKey]) {
        var onResolve = function (data) {
          translations(data.key, data.table);
          deferred.resolve(data.table);
        };
        onResolve.displayName = 'translationTableResolver';
        langPromises[langKey].then(onResolve, deferred.reject);
      } else {
        deferred.reject();
      }
      return deferred.promise;
    };

    /**
     * @name getFallbackTranslation
     * @private
     *
     * @description
     * Returns a promise that will resolve to the translation
     * or be rejected if no translation was found for the language.
     * This function is currently only used for fallback language translation.
     *
     * @param langKey The language to translate to.
     * @param translationId
     * @param interpolateParams
     * @param Interpolator
     * @param sanitizeStrategy
     * @returns {Q.promise}
     */
    var getFallbackTranslation = function (langKey, translationId, interpolateParams, Interpolator, sanitizeStrategy) {
      var deferred = $q.defer();

      var onResolve = function (translationTable) {
        if (Object.prototype.hasOwnProperty.call(translationTable, translationId) && translationTable[translationId] !== null) {
          Interpolator.setLocale(langKey);
          var translation = translationTable[translationId];
          if (translation.substr(0, 2) === '@:') {
            getFallbackTranslation(langKey, translation.substr(2), interpolateParams, Interpolator, sanitizeStrategy)
              .then(deferred.resolve, deferred.reject);
          } else {
            var interpolatedValue = Interpolator.interpolate(translationTable[translationId], interpolateParams, 'service', sanitizeStrategy, translationId);
            interpolatedValue = applyPostProcessing(translationId, translationTable[translationId], interpolatedValue, interpolateParams, langKey);

            deferred.resolve(interpolatedValue);

          }
          Interpolator.setLocale($uses);
        } else {
          deferred.reject();
        }
      };
      onResolve.displayName = 'fallbackTranslationResolver';

      getTranslationTable(langKey).then(onResolve, deferred.reject);

      return deferred.promise;
    };

    /**
     * @name getFallbackTranslationInstant
     * @private
     *
     * @description
     * Returns a translation
     * This function is currently only used for fallback language translation.
     *
     * @param langKey The language to translate to.
     * @param translationId
     * @param interpolateParams
     * @param Interpolator
     * @param sanitizeStrategy sanitize strategy override
     *
     * @returns {string} translation
     */
    var getFallbackTranslationInstant = function (langKey, translationId, interpolateParams, Interpolator, sanitizeStrategy) {
      var result, translationTable = $translationTable[langKey];

      if (translationTable && Object.prototype.hasOwnProperty.call(translationTable, translationId) && translationTable[translationId] !== null) {
        Interpolator.setLocale(langKey);
        result = Interpolator.interpolate(translationTable[translationId], interpolateParams, 'filter', sanitizeStrategy, translationId);
        result = applyPostProcessing(translationId, translationTable[translationId], result, interpolateParams, langKey, sanitizeStrategy);
        // workaround for TrustedValueHolderType
        if (!angular.isString(result) && angular.isFunction(result.$$unwrapTrustedValue)) {
          var result2 = result.$$unwrapTrustedValue();
          if (result2.substr(0, 2) === '@:') {
            return getFallbackTranslationInstant(langKey, result2.substr(2), interpolateParams, Interpolator, sanitizeStrategy);
          }
        } else if (result.substr(0, 2) === '@:') {
          return getFallbackTranslationInstant(langKey, result.substr(2), interpolateParams, Interpolator, sanitizeStrategy);
        }
        Interpolator.setLocale($uses);
      }

      return result;
    };


    /**
     * @name translateByHandler
     * @private
     *
     * Translate by missing translation handler.
     *
     * @param translationId
     * @param interpolateParams
     * @param defaultTranslationText
     * @param sanitizeStrategy sanitize strategy override
     *
     * @returns translation created by $missingTranslationHandler or translationId is $missingTranslationHandler is
     * absent
     */
    var translateByHandler = function (translationId, interpolateParams, defaultTranslationText, sanitizeStrategy) {
      // If we have a handler factory - we might also call it here to determine if it provides
      // a default text for a translationid that can't be found anywhere in our tables
      if ($missingTranslationHandlerFactory) {
        return $injector.get($missingTranslationHandlerFactory)(translationId, $uses, interpolateParams, defaultTranslationText, sanitizeStrategy);
      } else {
        return translationId;
      }
    };

    /**
     * @name resolveForFallbackLanguage
     * @private
     *
     * Recursive helper function for fallbackTranslation that will sequentially look
     * for a translation in the fallbackLanguages starting with fallbackLanguageIndex.
     *
     * @param fallbackLanguageIndex
     * @param translationId
     * @param interpolateParams
     * @param Interpolator
     * @param defaultTranslationText
     * @param sanitizeStrategy
     * @returns {Q.promise} Promise that will resolve to the translation.
     */
    var resolveForFallbackLanguage = function (fallbackLanguageIndex, translationId, interpolateParams, Interpolator, defaultTranslationText, sanitizeStrategy) {
      var deferred = $q.defer();

      if (fallbackLanguageIndex < $fallbackLanguage.length) {
        var langKey = $fallbackLanguage[fallbackLanguageIndex];
        getFallbackTranslation(langKey, translationId, interpolateParams, Interpolator, sanitizeStrategy).then(
          function (data) {
            deferred.resolve(data);
          },
          function () {
            // Look in the next fallback language for a translation.
            // It delays the resolving by passing another promise to resolve.
            return resolveForFallbackLanguage(fallbackLanguageIndex + 1, translationId, interpolateParams, Interpolator, defaultTranslationText, sanitizeStrategy).then(deferred.resolve, deferred.reject);
          }
        );
      } else {
        // No translation found in any fallback language
        // if a default translation text is set in the directive, then return this as a result
        if (defaultTranslationText) {
          deferred.resolve(defaultTranslationText);
        } else {
          var missingTranslationHandlerTranslation = translateByHandler(translationId, interpolateParams, defaultTranslationText);

          // if no default translation is set and an error handler is defined, send it to the handler
          // and then return the result if it isn't undefined
          if ($missingTranslationHandlerFactory && missingTranslationHandlerTranslation) {
            deferred.resolve(missingTranslationHandlerTranslation);
          } else {
            deferred.reject(applyNotFoundIndicators(translationId));
          }
        }
      }
      return deferred.promise;
    };

    /**
     * @name resolveForFallbackLanguageInstant
     * @private
     *
     * Recursive helper function for fallbackTranslation that will sequentially look
     * for a translation in the fallbackLanguages starting with fallbackLanguageIndex.
     *
     * @param fallbackLanguageIndex
     * @param translationId
     * @param interpolateParams
     * @param Interpolator
     * @param sanitizeStrategy
     * @returns {string} translation
     */
    var resolveForFallbackLanguageInstant = function (fallbackLanguageIndex, translationId, interpolateParams, Interpolator, sanitizeStrategy) {
      var result;

      if (fallbackLanguageIndex < $fallbackLanguage.length) {
        var langKey = $fallbackLanguage[fallbackLanguageIndex];
        result = getFallbackTranslationInstant(langKey, translationId, interpolateParams, Interpolator, sanitizeStrategy);
        if (!result && result !== '') {
          result = resolveForFallbackLanguageInstant(fallbackLanguageIndex + 1, translationId, interpolateParams, Interpolator);
        }
      }
      return result;
    };

    /**
     * Translates with the usage of the fallback languages.
     *
     * @param translationId
     * @param interpolateParams
     * @param Interpolator
     * @param defaultTranslationText
     * @param sanitizeStrategy
     * @returns {Q.promise} Promise, that resolves to the translation.
     */
    var fallbackTranslation = function (translationId, interpolateParams, Interpolator, defaultTranslationText, sanitizeStrategy) {
      // Start with the fallbackLanguage with index 0
      return resolveForFallbackLanguage((startFallbackIteration > 0 ? startFallbackIteration : fallbackIndex), translationId, interpolateParams, Interpolator, defaultTranslationText, sanitizeStrategy);
    };

    /**
     * Translates with the usage of the fallback languages.
     *
     * @param translationId
     * @param interpolateParams
     * @param Interpolator
     * @param sanitizeStrategy
     * @returns {String} translation
     */
    var fallbackTranslationInstant = function (translationId, interpolateParams, Interpolator, sanitizeStrategy) {
      // Start with the fallbackLanguage with index 0
      return resolveForFallbackLanguageInstant((startFallbackIteration > 0 ? startFallbackIteration : fallbackIndex), translationId, interpolateParams, Interpolator, sanitizeStrategy);
    };

    var determineTranslation = function (translationId, interpolateParams, interpolationId, defaultTranslationText, uses, sanitizeStrategy) {

      var deferred = $q.defer();

      var table = uses ? $translationTable[uses] : $translationTable,
        Interpolator = (interpolationId) ? interpolatorHashMap[interpolationId] : defaultInterpolator;

      // if the translation id exists, we can just interpolate it
      if (table && Object.prototype.hasOwnProperty.call(table, translationId) && table[translationId] !== null) {
        var translation = table[translationId];

        // If using link, rerun $translate with linked translationId and return it
        if (translation.substr(0, 2) === '@:') {

          $translate(translation.substr(2), interpolateParams, interpolationId, defaultTranslationText, uses, sanitizeStrategy)
            .then(deferred.resolve, deferred.reject);
        } else {
          //
          var resolvedTranslation = Interpolator.interpolate(translation, interpolateParams, 'service', sanitizeStrategy, translationId);
          resolvedTranslation = applyPostProcessing(translationId, translation, resolvedTranslation, interpolateParams, uses);
          deferred.resolve(resolvedTranslation);
        }
      } else {
        var missingTranslationHandlerTranslation;
        // for logging purposes only (as in $translateMissingTranslationHandlerLog), value is not returned to promise
        if ($missingTranslationHandlerFactory && !pendingLoader) {
          missingTranslationHandlerTranslation = translateByHandler(translationId, interpolateParams, defaultTranslationText);
        }

        // since we couldn't translate the inital requested translation id,
        // we try it now with one or more fallback languages, if fallback language(s) is
        // configured.
        if (uses && $fallbackLanguage && $fallbackLanguage.length) {
          fallbackTranslation(translationId, interpolateParams, Interpolator, defaultTranslationText, sanitizeStrategy)
            .then(function (translation) {
              deferred.resolve(translation);
            }, function (_translationId) {
              deferred.reject(applyNotFoundIndicators(_translationId));
            });
        } else if ($missingTranslationHandlerFactory && !pendingLoader && missingTranslationHandlerTranslation) {
          // looks like the requested translation id doesn't exists.
          // Now, if there is a registered handler for missing translations and no
          // asyncLoader is pending, we execute the handler
          if (defaultTranslationText) {
            deferred.resolve(defaultTranslationText);
          } else {
            deferred.resolve(missingTranslationHandlerTranslation);
          }
        } else {
          if (defaultTranslationText) {
            deferred.resolve(defaultTranslationText);
          } else {
            deferred.reject(applyNotFoundIndicators(translationId));
          }
        }
      }
      return deferred.promise;
    };

    var determineTranslationInstant = function (translationId, interpolateParams, interpolationId, uses, sanitizeStrategy) {

      var result, table = uses ? $translationTable[uses] : $translationTable,
        Interpolator = defaultInterpolator;

      // if the interpolation id exists use custom interpolator
      if (interpolatorHashMap && Object.prototype.hasOwnProperty.call(interpolatorHashMap, interpolationId)) {
        Interpolator = interpolatorHashMap[interpolationId];
      }

      // if the translation id exists, we can just interpolate it
      if (table && Object.prototype.hasOwnProperty.call(table, translationId) && table[translationId] !== null) {
        var translation = table[translationId];

        // If using link, rerun $translate with linked translationId and return it
        if (translation.substr(0, 2) === '@:') {
          result = determineTranslationInstant(translation.substr(2), interpolateParams, interpolationId, uses, sanitizeStrategy);
        } else {
          result = Interpolator.interpolate(translation, interpolateParams, 'filter', sanitizeStrategy, translationId);
          result = applyPostProcessing(translationId, translation, result, interpolateParams, uses, sanitizeStrategy);
        }
      } else {
        var missingTranslationHandlerTranslation;
        // for logging purposes only (as in $translateMissingTranslationHandlerLog), value is not returned to promise
        if ($missingTranslationHandlerFactory && !pendingLoader) {
          missingTranslationHandlerTranslation = translateByHandler(translationId, interpolateParams, sanitizeStrategy);
        }

        // since we couldn't translate the inital requested translation id,
        // we try it now with one or more fallback languages, if fallback language(s) is
        // configured.
        if (uses && $fallbackLanguage && $fallbackLanguage.length) {
          fallbackIndex = 0;
          result = fallbackTranslationInstant(translationId, interpolateParams, Interpolator, sanitizeStrategy);
        } else if ($missingTranslationHandlerFactory && !pendingLoader && missingTranslationHandlerTranslation) {
          // looks like the requested translation id doesn't exists.
          // Now, if there is a registered handler for missing translations and no
          // asyncLoader is pending, we execute the handler
          result = missingTranslationHandlerTranslation;
        } else {
          result = applyNotFoundIndicators(translationId);
        }
      }

      return result;
    };

    var clearNextLangAndPromise = function (key) {
      if ($nextLang === key) {
        $nextLang = undefined;
      }
      langPromises[key] = undefined;
    };

    var applyPostProcessing = function (translationId, translation, resolvedTranslation, interpolateParams, uses, sanitizeStrategy) {
      var fn = postProcessFn;

      if (fn) {

        if (typeof(fn) === 'string') {
          // getting on-demand instance
          fn = $injector.get(fn);
        }
        if (fn) {
          return fn(translationId, translation, resolvedTranslation, interpolateParams, uses, sanitizeStrategy);
        }
      }

      return resolvedTranslation;
    };

    var loadTranslationsIfMissing = function (key) {
      if (!$translationTable[key] && $loaderFactory && !langPromises[key]) {
        langPromises[key] = loadAsync(key).then(function (translation) {
          translations(translation.key, translation.table);
          return translation;
        });
      }
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#preferredLanguage
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns the language key for the preferred language.
     *
     * @param {string} langKey language String or Array to be used as preferredLanguage (changing at runtime)
     *
     * @return {string} preferred language key
     */
    $translate.preferredLanguage = function (langKey) {
      if (langKey) {
        setupPreferredLanguage(langKey);
      }
      return $preferredLanguage;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#cloakClassName
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns the configured class name for `translate-cloak` directive.
     *
     * @return {string} cloakClassName
     */
    $translate.cloakClassName = function () {
      return $cloakClassName;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#nestedObjectDelimeter
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns the configured delimiter for nested namespaces.
     *
     * @return {string} nestedObjectDelimeter
     */
    $translate.nestedObjectDelimeter = function () {
      return $nestedObjectDelimeter;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#fallbackLanguage
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns the language key for the fallback languages or sets a new fallback stack.
     * It is recommended to call this before {@link pascalprecht.translate.$translateProvider#preferredLanguage preferredLanguage()}.
     *
     * @param {string=} langKey language String or Array of fallback languages to be used (to change stack at runtime)
     *
     * @return {string||array} fallback language key
     */
    $translate.fallbackLanguage = function (langKey) {
      if (langKey !== undefined && langKey !== null) {
        fallbackStack(langKey);

        // as we might have an async loader initiated and a new translation language might have been defined
        // we need to add the promise to the stack also. So - iterate.
        if ($loaderFactory) {
          if ($fallbackLanguage && $fallbackLanguage.length) {
            for (var i = 0, len = $fallbackLanguage.length; i < len; i++) {
              if (!langPromises[$fallbackLanguage[i]]) {
                langPromises[$fallbackLanguage[i]] = loadAsync($fallbackLanguage[i]);
              }
            }
          }
        }
        $translate.use($translate.use());
      }
      if ($fallbackWasString) {
        return $fallbackLanguage[0];
      } else {
        return $fallbackLanguage;
      }

    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#useFallbackLanguage
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Sets the first key of the fallback language stack to be used for translation.
     * Therefore all languages in the fallback array BEFORE this key will be skipped!
     *
     * @param {string=} langKey Contains the langKey the iteration shall start with. Set to false if you want to
     * get back to the whole stack
     */
    $translate.useFallbackLanguage = function (langKey) {
      if (langKey !== undefined && langKey !== null) {
        if (!langKey) {
          startFallbackIteration = 0;
        } else {
          var langKeyPosition = indexOf($fallbackLanguage, langKey);
          if (langKeyPosition > -1) {
            startFallbackIteration = langKeyPosition;
          }
        }

      }

    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#proposedLanguage
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns the language key of language that is currently loaded asynchronously.
     *
     * @return {string} language key
     */
    $translate.proposedLanguage = function () {
      return $nextLang;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#storage
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns registered storage.
     *
     * @return {object} Storage
     */
    $translate.storage = function () {
      return Storage;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#negotiateLocale
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns a language key based on available languages and language aliases. If a
     * language key cannot be resolved, returns undefined.
     *
     * If no or a falsy key is given, returns undefined.
     *
     * @param {string} [key] Language key
     * @return {string|undefined} Language key or undefined if no language key is found.
     */
    $translate.negotiateLocale = negotiateLocale;

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#use
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Tells angular-translate which language to use by given language key. This method is
     * used to change language at runtime. It also takes care of storing the language
     * key in a configured store to let your app remember the choosed language.
     *
     * When trying to 'use' a language which isn't available it tries to load it
     * asynchronously with registered loaders.
     *
     * Returns promise object with loaded language file data or string of the currently used language.
     *
     * If no or a falsy key is given it returns the currently used language key.
     * The returned string will be ```undefined``` if setting up $translate hasn't finished.
     * @example
     * $translate.use("en_US").then(function(data){
       *   $scope.text = $translate("HELLO");
       * });
     *
     * @param {string=} key Language key
     * @return {object|string} Promise with loaded language data or the language key if a falsy param was given.
     */
    $translate.use = function (key) {
      if (!key) {
        return $uses;
      }

      var deferred = $q.defer();
      deferred.promise.then(null, angular.noop); // AJS "Possibly unhandled rejection"

      $rootScope.$emit('$translateChangeStart', {language : key});

      // Try to get the aliased language key
      var aliasedKey = negotiateLocale(key);
      // Ensure only registered language keys will be loaded
      if ($availableLanguageKeys.length > 0 && !aliasedKey) {
        return $q.reject(key);
      }

      if (aliasedKey) {
        key = aliasedKey;
      }

      // if there isn't a translation table for the language we've requested,
      // we load it asynchronously
      $nextLang = key;
      if (($forceAsyncReloadEnabled || !$translationTable[key]) && $loaderFactory && !langPromises[key]) {
        langPromises[key] = loadAsync(key).then(function (translation) {
          translations(translation.key, translation.table);
          deferred.resolve(translation.key);
          if ($nextLang === key) {
            useLanguage(translation.key);
          }
          return translation;
        }, function (key) {
          $rootScope.$emit('$translateChangeError', {language : key});
          deferred.reject(key);
          $rootScope.$emit('$translateChangeEnd', {language : key});
          return $q.reject(key);
        });
        langPromises[key]['finally'](function () {
          clearNextLangAndPromise(key);
        })['catch'](angular.noop); // we don't care about errors (clearing)
      } else if (langPromises[key]) {
        // we are already loading this asynchronously
        // resolve our new deferred when the old langPromise is resolved
        langPromises[key].then(function (translation) {
          if ($nextLang === translation.key) {
            useLanguage(translation.key);
          }
          deferred.resolve(translation.key);
          return translation;
        }, function (key) {
          // find first available fallback language if that request has failed
          if (!$uses && $fallbackLanguage && $fallbackLanguage.length > 0 && $fallbackLanguage[0] !== key) {
            return $translate.use($fallbackLanguage[0]).then(deferred.resolve, deferred.reject);
          } else {
            return deferred.reject(key);
          }
        });
      } else {
        deferred.resolve(key);
        useLanguage(key);
      }

      return deferred.promise;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#resolveClientLocale
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * This returns the current browser/client's language key. The result is processed with the configured uniform tag resolver.
     *
     * @returns {string} the current client/browser language key
     */
    $translate.resolveClientLocale = function () {
      return getLocale();
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#storageKey
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns the key for the storage.
     *
     * @return {string} storage key
     */
    $translate.storageKey = function () {
      return storageKey();
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#isPostCompilingEnabled
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns whether post compiling is enabled or not
     *
     * @return {bool} storage key
     */
    $translate.isPostCompilingEnabled = function () {
      return $postCompilingEnabled;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#isForceAsyncReloadEnabled
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns whether force async reload is enabled or not
     *
     * @return {boolean} forceAsyncReload value
     */
    $translate.isForceAsyncReloadEnabled = function () {
      return $forceAsyncReloadEnabled;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#isKeepContent
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns whether keepContent or not
     *
     * @return {boolean} keepContent value
     */
    $translate.isKeepContent = function () {
      return $keepContent;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#refresh
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Refreshes a translation table pointed by the given langKey. If langKey is not specified,
     * the module will drop all existent translation tables and load new version of those which
     * are currently in use.
     *
     * Refresh means that the module will drop target translation table and try to load it again.
     *
     * In case there are no loaders registered the refresh() method will throw an Error.
     *
     * If the module is able to refresh translation tables refresh() method will broadcast
     * $translateRefreshStart and $translateRefreshEnd events.
     *
     * @example
     * // this will drop all currently existent translation tables and reload those which are
     * // currently in use
     * $translate.refresh();
     * // this will refresh a translation table for the en_US language
     * $translate.refresh('en_US');
     *
     * @param {string} langKey A language key of the table, which has to be refreshed
     *
     * @return {promise} Promise, which will be resolved in case a translation tables refreshing
     * process is finished successfully, and reject if not.
     */
    $translate.refresh = function (langKey) {
      if (!$loaderFactory) {
        throw new Error('Couldn\'t refresh translation table, no loader registered!');
      }

      $rootScope.$emit('$translateRefreshStart', {language : langKey});

      var deferred = $q.defer(), updatedLanguages = {};

      //private helper
      function loadNewData(languageKey) {
        var promise = loadAsync(languageKey);
        //update the load promise cache for this language
        langPromises[languageKey] = promise;
        //register a data handler for the promise
        promise.then(function (data) {
            //clear the cache for this language
            $translationTable[languageKey] = {};
            //add the new data for this language
            translations(languageKey, data.table);
            //track that we updated this language
            updatedLanguages[languageKey] = true;
          },
          //handle rejection to appease the $q validation
          angular.noop);
        return promise;
      }

      //set up post-processing
      deferred.promise.then(
        function () {
          for (var key in $translationTable) {
            if ($translationTable.hasOwnProperty(key)) {
              //delete cache entries that were not updated
              if (!(key in updatedLanguages)) {
                delete $translationTable[key];
              }
            }
          }
          if ($uses) {
            useLanguage($uses);
          }
        },
        //handle rejection to appease the $q validation
        angular.noop
      )['finally'](
        function () {
          $rootScope.$emit('$translateRefreshEnd', {language : langKey});
        }
      );

      if (!langKey) {
        // if there's no language key specified we refresh ALL THE THINGS!
        var languagesToReload = $fallbackLanguage && $fallbackLanguage.slice() || [];
        if ($uses && languagesToReload.indexOf($uses) === -1) {
          languagesToReload.push($uses);
        }
        $q.all(languagesToReload.map(loadNewData)).then(deferred.resolve, deferred.reject);

      } else if ($translationTable[langKey]) {
        //just refresh the specified language cache
        loadNewData(langKey).then(deferred.resolve, deferred.reject);

      } else {
        deferred.reject();
      }

      return deferred.promise;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#instant
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns a translation instantly from the internal state of loaded translation. All rules
     * regarding the current language, the preferred language of even fallback languages will be
     * used except any promise handling. If a language was not found, an asynchronous loading
     * will be invoked in the background.
     *
     * @param {string|array} translationId A token which represents a translation id
     *                                     This can be optionally an array of translation ids which
     *                                     results that the function's promise returns an object where
     *                                     each key is the translation id and the value the translation.
     * @param {object=} [interpolateParams={}] Params
     * @param {string=} [interpolationId=undefined] The id of the interpolation to use (use default unless set via useInterpolation())
     * @param {string=} [forceLanguage=false] A language to be used instead of the current language
     * @param {string=} [sanitizeStrategy=undefined] force sanitize strategy for this call instead of using the configured one (use default unless set)
     *
     * @return {string|object} translation
     */
    $translate.instant = function (translationId, interpolateParams, interpolationId, forceLanguage, sanitizeStrategy) {

      // we don't want to re-negotiate $uses
      var uses = (forceLanguage && forceLanguage !== $uses) ? // we don't want to re-negotiate $uses
        (negotiateLocale(forceLanguage) || forceLanguage) : $uses;

      // Detect undefined and null values to shorten the execution and prevent exceptions
      if (translationId === null || angular.isUndefined(translationId)) {
        return translationId;
      }

      // Check forceLanguage is present
      if (forceLanguage) {
        loadTranslationsIfMissing(forceLanguage);
      }

      // Duck detection: If the first argument is an array, a bunch of translations was requested.
      // The result is an object.
      if (angular.isArray(translationId)) {
        var results = {};
        for (var i = 0, c = translationId.length; i < c; i++) {
          results[translationId[i]] = $translate.instant(translationId[i], interpolateParams, interpolationId, forceLanguage, sanitizeStrategy);
        }
        return results;
      }

      // We discarded unacceptable values. So we just need to verify if translationId is empty String
      if (angular.isString(translationId) && translationId.length < 1) {
        return translationId;
      }

      // trim off any whitespace
      if (translationId) {
        translationId = trim.apply(translationId);
      }

      var result, possibleLangKeys = [];
      if ($preferredLanguage) {
        possibleLangKeys.push($preferredLanguage);
      }
      if (uses) {
        possibleLangKeys.push(uses);
      }
      if ($fallbackLanguage && $fallbackLanguage.length) {
        possibleLangKeys = possibleLangKeys.concat($fallbackLanguage);
      }
      for (var j = 0, d = possibleLangKeys.length; j < d; j++) {
        var possibleLangKey = possibleLangKeys[j];
        if ($translationTable[possibleLangKey]) {
          if (typeof $translationTable[possibleLangKey][translationId] !== 'undefined') {
            result = determineTranslationInstant(translationId, interpolateParams, interpolationId, uses, sanitizeStrategy);
          }
        }
        if (typeof result !== 'undefined') {
          break;
        }
      }

      if (!result && result !== '') {
        if ($notFoundIndicatorLeft || $notFoundIndicatorRight) {
          result = applyNotFoundIndicators(translationId);
        } else {
          // Return translation of default interpolator if not found anything.
          result = defaultInterpolator.interpolate(translationId, interpolateParams, 'filter', sanitizeStrategy);

          // looks like the requested translation id doesn't exists.
          // Now, if there is a registered handler for missing translations and no
          // asyncLoader is pending, we execute the handler
          var missingTranslationHandlerTranslation;
          if ($missingTranslationHandlerFactory && !pendingLoader) {
            missingTranslationHandlerTranslation = translateByHandler(translationId, interpolateParams, sanitizeStrategy);
          }

          if ($missingTranslationHandlerFactory && !pendingLoader && missingTranslationHandlerTranslation) {
            result = missingTranslationHandlerTranslation;
          }
        }
      }

      return result;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#versionInfo
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns the current version information for the angular-translate library
     *
     * @return {string} angular-translate version
     */
    $translate.versionInfo = function () {
      return version;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#loaderCache
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns the defined loaderCache.
     *
     * @return {boolean|string|object} current value of loaderCache
     */
    $translate.loaderCache = function () {
      return loaderCache;
    };

    // internal purpose only
    $translate.directivePriority = function () {
      return directivePriority;
    };

    // internal purpose only
    $translate.statefulFilter = function () {
      return statefulFilter;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#isReady
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns whether the service is "ready" to translate (i.e. loading 1st language).
     *
     * See also {@link pascalprecht.translate.$translate#methods_onReady onReady()}.
     *
     * @return {boolean} current value of ready
     */
    $translate.isReady = function () {
      return $isReady;
    };

    var $onReadyDeferred = $q.defer();
    $onReadyDeferred.promise.then(function () {
      $isReady = true;
    });

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#onReady
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Calls the function provided or resolved the returned promise after the service is "ready" to translate (i.e. loading 1st language).
     *
     * See also {@link pascalprecht.translate.$translate#methods_isReady isReady()}.
     *
     * @param {Function=} fn Function to invoke when service is ready
     * @return {object} Promise resolved when service is ready
     */
    $translate.onReady = function (fn) {
      var deferred = $q.defer();
      if (angular.isFunction(fn)) {
        deferred.promise.then(fn);
      }
      if ($isReady) {
        deferred.resolve();
      } else {
        $onReadyDeferred.promise.then(deferred.resolve);
      }
      return deferred.promise;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#getAvailableLanguageKeys
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * This function simply returns the registered language keys being defined before in the config phase
     * With this, an application can use the array to provide a language selection dropdown or similar
     * without any additional effort
     *
     * @returns {object} returns the list of possibly registered language keys and mapping or null if not defined
     */
    $translate.getAvailableLanguageKeys = function () {
      if ($availableLanguageKeys.length > 0) {
        return $availableLanguageKeys;
      }
      return null;
    };

    /**
     * @ngdoc function
     * @name pascalprecht.translate.$translate#getTranslationTable
     * @methodOf pascalprecht.translate.$translate
     *
     * @description
     * Returns translation table by the given language key.
     *
     * Unless a language is provided it returns a translation table of the current one.
     * Note: If translation dictionary is currently downloading or in progress
     * it will return null.
     *
     * @param {string} langKey A token which represents a translation id
     *
     * @return {object} a copy of angular-translate $translationTable
     */
    $translate.getTranslationTable = function (langKey) {
      langKey = langKey || $translate.use();
      if (langKey && $translationTable[langKey]) {
        return angular.copy($translationTable[langKey]);
      }
      return null;
    };

    // Whenever $translateReady is being fired, this will ensure the state of $isReady
    var globalOnReadyListener = $rootScope.$on('$translateReady', function () {
      $onReadyDeferred.resolve();
      globalOnReadyListener(); // one time only
      globalOnReadyListener = null;
    });
    var globalOnChangeListener = $rootScope.$on('$translateChangeEnd', function () {
      $onReadyDeferred.resolve();
      globalOnChangeListener(); // one time only
      globalOnChangeListener = null;
    });

    if ($loaderFactory) {

      // If at least one async loader is defined and there are no
      // (default) translations available we should try to load them.
      if (angular.equals($translationTable, {})) {
        if ($translate.use()) {
          $translate.use($translate.use());
        }
      }

      // Also, if there are any fallback language registered, we start
      // loading them asynchronously as soon as we can.
      if ($fallbackLanguage && $fallbackLanguage.length) {
        var processAsyncResult = function (translation) {
          translations(translation.key, translation.table);
          $rootScope.$emit('$translateChangeEnd', {language : translation.key});
          return translation;
        };
        for (var i = 0, len = $fallbackLanguage.length; i < len; i++) {
          var fallbackLanguageId = $fallbackLanguage[i];
          if ($forceAsyncReloadEnabled || !$translationTable[fallbackLanguageId]) {
            langPromises[fallbackLanguageId] = loadAsync(fallbackLanguageId).then(processAsyncResult);
          }
        }
      }
    } else {
      $rootScope.$emit('$translateReady', {language : $translate.use()});
    }

    return $translate;
  };
}

$translate.displayName = 'displayName';