code: function _loginEvrythng(credentials, successCallback, errorCallback) {
  
      if(!credentials || Utils.isFunction(credentials)) {
        throw new TypeError('Credentials are missing.');
      }
  
      // Send the authentication request to the REST API, which is a Promise.
      // Note that the context is passed from the above *app.login()* method
      // until the raw call in order to pass the correct scope's Api Key.
      return _authEvrythng.call(this, credentials).then(function (userResponse) {
  
        // Login was successful, apply callback and propagate response to the
        // next promise handler.
        if(successCallback) {
          Logger.warnCallbackDeprecation();
          successCallback(userResponse);
        }
        return userResponse;
  
      }, function (response) {
  
        // Login was not successful, call error callback and re-throw error.
        if(errorCallback) {
          Logger.warnCallbackDeprecation();
          errorCallback(response);
        }
        throw response;
  
      });
    }
docs: Login with Evrythng using either the *email* or *id* properties.