使用react redux probem获取异步数据

// actionTypes.js
export const FETCH_DATA_REQUEST = 'FETCH_DATA_REQUEST';
export const FETCH_DATA_SUCCESS = 'FETCH_DATA_SUCCESS';
export const FETCH_DATA_FAILURE = 'FETCH_DATA_FAILURE';

// actions.js
import { FETCH_DATA_REQUEST, FETCH_DATA_SUCCESS, FETCH_DATA_FAILURE } from './actionTypes';

export const fetchDataRequest = () => ({
  type: FETCH_DATA_REQUEST
});

export const fetchDataSuccess = (data) => ({
  type: FETCH_DATA_SUCCESS,
  payload: data
});

export const fetchDataFailure = (error) => ({
  type: FETCH_DATA_FAILURE,
  payload: error
});

export const fetchData = () => {
  return (dispatch) => {
    dispatch(fetchDataRequest());
    fetch('https://api.example.com/data')
      .then(response => response.json())
      .then(data => dispatch(fetchDataSuccess(data)))
      .catch(error => dispatch(fetchDataFailure(error)));
  };
};

// reducer.js
import { FETCH_DATA_REQUEST, FETCH_DATA_SUCCESS, FETCH_DATA_FAILURE } from './actionTypes';

const initialState = {
  loading: false,
  data: [],
  error: ''
};

const dataReducer = (state = initialState, action) => {
  switch (action.type) {
    case FETCH_DATA_REQUEST:
      return { ...state, loading: true };
    case FETCH_DATA_SUCCESS:
      return { loading: false, data: action.payload, error: '' };
    case FETCH_DATA_FAILURE:
      return { loading: false, data: [], error: action.payload };
    default:
      return state;
  }
};

export default dataReducer;

// App.js
import React, { useEffect } from 'react';
import { useDispatch, useSelector } from 'react-redux';
import { fetchData } from './actions';

const App = () => {
  const dispatch = useDispatch();
  const { loading, data, error } = useSelector(state => state.data);

  useEffect(() => {
    dispatch(fetchData());
  }, [dispatch]);

  return (
    <div>
      {loading ? (
        <p>Loading...</p>
      ) : error ? (
        <p>Error: {error}</p>
      ) : (
        <ul>
          {data.map(item => (
            <li key={item.id}>{item.name}</li>
          ))}
        </ul>
      )}
    </div>
  );
};

export default App;