【前端知识】React 基础巩固(三十六)——RTK中的异步操作

React 基础巩固(三十六)——RTK中的异步操作

一、RTK中使用异步操作

1. 引入RTK中的createAsyncThunk，在extraReducers中监听执行状态

   import { createSlice, createAsyncThunk } from "@reduxjs/toolkit";
   import axios from "axios";export const fetchHomeMultidataAction = createAsyncThunk("fetch/homemultidata",async () => {const res = await axios.get("http://123.207.32.32:8000/home/multidata");return res.data;}
   );const homeSlice = createSlice({name: "home",initialState: {banners: [],recommends: [],},reducers: {changeBanners(state, { payload }) {state.banners = payload;},changeRecommends(state, { payload }) {state.recommends = payload;},},extraReducers: {[fetchHomeMultidataAction.pending](state, action) {console.log("fetchHomeMultidataAction pending");},[fetchHomeMultidataAction.fulfilled](state, { payload }) {console.log("fetchHomeMultidataAction fulfilled");state.banners = payload.data.banner.list;state.recommends = payload.data.recommend.list;},[fetchHomeMultidataAction.rejected](state, action) {console.log("fetchHomeMultidataAction rejected");},},
   });export const { changeBanners, changeRecommends } = homeSlice.actions;
   export default homeSlice.reducer;

2. 在界面中引入所需的异步操作Action

   import React, { PureComponent } from "react";
   import { connect } from "react-redux";
   import { addNumber } from "../store/features/counter";
   import { fetchHomeMultidataAction } from "../store/features/home";export class Home extends PureComponent {componentDidMount() {this.props.fetchHomeMultidata()}addNumber(num) {this.props.addNumber(num);}render() {const { counter } = this.props;return (<div>home:{counter}<button onClick={(e) => this.addNumber(5)}>+5</button>
   <button onClick={(e) => this.addNumber(8)}>+8</button>
   <button onClick={(e) => this.addNumber(18)}>+18</button>
   </div>
   );
   }
   }const mapStateToProps = (state) => ({counter: state.counter.counter,
   });const mapDispatchToProps = (dispatch) => ({addNumber(num) {dispatch(addNumber(num));},fetchHomeMultidata(){dispatch(fetchHomeMultidataAction())}
   });export default connect(mapStateToProps, mapDispatchToProps)(Home);

3. 查看运行结果
   

二、extraReducer的另外一种写法（链式调用）

1. extraReducer还可以传入一个函数，函数接受一个builder参数：

extraReducers: (builder) => {builder.addCase(fetchHomeMultidataAction.pending, (state, action) => {console.log("fetchHomeMultidataAction pending");}).addCase(fetchHomeMultidataAction.fulfilled, (state, { payload }) => {console.log("fetchHomeMultidataAction fulfilled");state.banners = payload.data.banner.list;state.recommends = payload.data.recommend.list;}).addCase(fetchHomeMultidataAction.rejected, (state, action) => {console.log("fetchHomeMultidataAction rejected");});
},

2. 查看运行结果，与之前的写法结果一致