配置Redux DevTools

Redux DevTools需要主动配置才可以在浏览器内查看状态

import {createStore,applyMiddleware,combineReducers,compose} from "redux"

import thunk from "redux-thunk" //中间件，用来处理异步请求

const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose
let store =createStore(rootReducer,composeEnhancers(applyMiddleware(thunk)))