在继续观察redux之前，请等待第二次异步操作

// 定义一个异步action
const fetchData = () => {
  return async (dispatch) => {
    dispatch({ type: 'FETCH_DATA_START' });

    try {
      const response = await fetch('https://api.example.com/data');
      const data = await response.json();

      dispatch({ type: 'FETCH_DATA_SUCCESS', payload: data });
    } catch (error) {
      dispatch({ type: 'FETCH_DATA_FAILURE', payload: error.message });
    }
  };
};

// 在组件中dispatch异步action
dispatch(fetchData());

// 定义一个saga
function* fetchDataSaga() {
  try {
    const response = yield call(fetch, 'https://api.example.com/data');
    const data = yield call([response, 'json']);

    yield put({ type: 'FETCH_DATA_SUCCESS', payload: data });
  } catch (error) {
    yield put({ type: 'FETCH_DATA_FAILURE', payload: error.message });
  }
}

// 在根saga中监听action并执行saga
function* rootSaga() {
  yield takeEvery('FETCH_DATA', fetchDataSaga);
}

// 在应用程序中启动saga
sagaMiddleware.run(rootSaga);

// 在组件中dispatch一个action
dispatch({ type: 'FETCH_DATA' });