text: define(function (require) {
    return function mapExistsProvider(Promise) {
      return function (filter) {
        var key;
        var value;
        if (filter.exists) {
          key = 'exists';
          value = filter.exists.field;
          return Promise.resolve({ key: key, value: value });
        }
        return Promise.reject(filter);
      };
    };
  });
  