Username Validation

function.js

  vm.username = function($viewValue, $modelValue, scope) {

    // check if username matches regex before validating
    var value = $modelValue || $viewValue, deferred = $q.defer();
    if (UserConfig.ID_REGEX.test(value)) {

      scope.options.templateOptions.loading = true;
      UserService.username(value).then(function() {

          deferred.reject(false);
          scope.options.templateOptions.loading = false;
        },
        function(error) {

          // server returns a 404 if a user w/ the username can't be found.
          // this is ok
          if (error && error.status === 404) {
            deferred.resolve(true);
          }
          else {
            deferred.resolve(false);
          }
          scope.options.templateOptions.loading = false;
        });
    }
    else {
      return $q(function (resolve) {
        scope.options.templateOptions.loading = false;
        resolve();
      });
    }

    return deferred.promise;
  };

rewrite.js

vm.username = function($viewValue, $modelValue, scope) {
  
  var value = $modelValue || $viewValue;
  if (UserConfig.ID_REGEX.test(value)) {
    scope.options.templateOptions.loading = true;
    return UserService.username(value)
      .then(function() {
        reject(false);
      }).catch(function(error) {
        if (error && error.status === 404) {
          resolve(true);
        } else {
          resolve(false);
        }
      }).finally(function() {
        scope.options.templateOptions.loading = false;
      });
  }
  
  scope.options.templateOptions.loading = false;
  
  return $q.resolve();
}