Asynchronous action processing data before sendin to the server

addressActions.js

 function saveAddress(address, serverApi) {
     return function(dispatch, getState) {
          dispatch({
              type: types.SAVE_ADDRESS,
              address: address
          });
          let cleanAddress = getState().address;
          return serverApi.saveAddress(cleanAddress).then((json) => {
              if (areEmailsDifferent(cleanAddress, address)) {
                  let response = Object.assign({}, json);
                  response.additionalMessage = messages.AddressSavedButSomeEmailsWhereWrong;
                  return response;
              }
              else {
                  return json;
              }
          });
     };
 }