old_contents: 'use strict';
  
  Object.defineProperty(exports, "__esModule", {
    value: true
  });
  exports.getInterfaceLanguage = getInterfaceLanguage;
  exports.validateTranslationKeys = validateTranslationKeys;
  function getInterfaceLanguage() {
    if (!!navigator && !!navigator.language) {
      return navigator.language;
    } else if (!!navigator && !!navigator.languages && !!navigator.languages[0]) {
      return navigator.languages[0];
    } else if (!!navigator && !!navigator.userLanguage) {
      return navigator.userLanguage;
    } else if (!!navigator && !!navigator.browserLanguage) {
      return navigator.browserLanguage;
    }
    return 'en-US';
  }
  
  function validateTranslationKeys(translationKeys) {
    var reservedNames = ['_interfaceLanguage', '_language', '_defaultLanguage', '_defaultLanguageFirstLevelKeys', '_props'];
    translationKeys.forEach(function (key) {
      if (reservedNames.indexOf(key) !== -1) {
        throw new Error(key + ' cannot be used as a key. It is a reserved word.');
      }
    });
  }
new_contents: 'use strict';
  
  Object.defineProperty(exports, "__esModule", {
    value: true
  });
  exports.getInterfaceLanguage = getInterfaceLanguage;
  exports.validateTranslationKeys = validateTranslationKeys;
  function getInterfaceLanguage() {
    var defaultLang = 'en-US';
  
    // Check if it's running on server side
    if (typeof window === 'undefined') {
      return defaultLang;
    }
  
    if (!!navigator && !!navigator.language) {
      return navigator.language;
    } else if (!!navigator && !!navigator.languages && !!navigator.languages[0]) {
      return navigator.languages[0];
    } else if (!!navigator && !!navigator.userLanguage) {
      return navigator.userLanguage;
    } else if (!!navigator && !!navigator.browserLanguage) {
      return navigator.browserLanguage;
    }
    return defaultLang;
  }
  
  function validateTranslationKeys(translationKeys) {
    var reservedNames = ['_interfaceLanguage', '_language', '_defaultLanguage', '_defaultLanguageFirstLevelKeys', '_props'];
    translationKeys.forEach(function (key) {
      if (reservedNames.indexOf(key) !== -1) {
        throw new Error(key + ' cannot be used as a key. It is a reserved word.');
      }
    });
  }
subject: Fix server side. Build to lib