code: function wrapHandler(handler) {
    return function (state) {
      for (var _len = arguments.length, args = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
        args[_key - 1] = arguments[_key];
      }
  
      return _lodash2.default.assign({}, state, handler.apply(undefined, [state].concat(args)));
    };
  }
docs: Wraps the handler function to allow returning only state diff.