如何在Redux中处理重复动作创建器样板

npm install redux-thunk

import { createStore, applyMiddleware } from 'redux';
import thunk from 'redux-thunk';
import rootReducer from './reducers';

const store = createStore(rootReducer, applyMiddleware(thunk));

export const fetchData = () => {
  return (dispatch, getState) => {
    const { data } = getState();
    
    // 如果数据已经存在，不再重复请求
    if (data.length > 0) {
      return;
    }
    
    // 发起异步请求
    dispatch({ type: 'FETCH_DATA_REQUEST' });
    fetch('https://api.example.com/data')
      .then(response => response.json())
      .then(data => {
        dispatch({ type: 'FETCH_DATA_SUCCESS', payload: data });
      })
      .catch(error => {
        dispatch({ type: 'FETCH_DATA_FAILURE', payload: error });
      });
  };
};