有条件地替换redux reducer中的state值

// 定义初始state
const initialState = {
  data: null,
  error: null
};

// 定义reducer
const reducer = (state = initialState, action) => {
  switch (action.type) {
    case 'FETCH_DATA_SUCCESS':
      // 根据条件更新state值
      if (action.payload.condition) {
        return {
          ...state,
          data: action.payload.data
        };
      }
      return state;
    case 'FETCH_DATA_FAILURE':
      return {
        ...state,
        error: action.payload.error
      };
    default:
      return state;
  }
};

// 创建store
const store = createStore(reducer);

// 在组件中使用store
const MyComponent = () => {
  const data = useSelector(state => state.data);
  const dispatch = useDispatch();

  useEffect(() => {
    // 模拟异步请求数据
    setTimeout(() => {
      // 根据条件分发不同的action
      if (condition) {
        dispatch({
          type: 'FETCH_DATA_SUCCESS',
          payload: {
            condition: true,
            data: newData
          }
        });
      } else {
        dispatch({
          type: 'FETCH_DATA_FAILURE',
          payload: {
            error: '请求失败'
          }
        });
      }
    }, 1000);
  }, []);

  return (
    <div>
      {data ? (
        <p>{data}</p>
      ) : (
        <p>Loading...</p>
      )}
    </div>
  );
};