src/store/index.js
import { createStore , compose, applyMiddleware} from 'redux';
import reducer from './reducer';
import reactSaga from 'redux-saga';
//生成store对象
const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;
const store = createStore(reducer, composeEnhancers(
applyMiddleware(reactSaga)
)); //内部会第一次调用reducer函数,得到初始state
export default store;