React 基础巩固(三十五)——ReduxToolKit (RTK)

一、RTK介绍

1. Redux Tool Kit （RTK）是官方推荐的编写Redux逻辑的方法，旨在成为编写Redux逻辑的标准方式，从而解决上面提到的问题。

2. RTK的核心API主要有如下几个：

   • configureStore：包装createStore以提供简化的配置选项和良好的默认值。它可以自动组合你的slice reducer，添加你提供的任何Redux中间件，redux-thunk默认包含，并启用Redux DevTools Extension。

     参数	描述
     reducer	将slice中的reducer组成一个对象传入此处
     middleware	传入中间件
     devTools	是否配置devTools工具，默认为true

   • createSlice：接受reducer函数的对象、切片名和初始状态值，并自动生成切片reducer，并带有相应的actions。

     参数	描述
     name	用户标记slice的名次
     initialState	初始化值
     reducers	reducer函数，对象类型，可添加多个
     createSlice	返回值是一个对象，包含所有的actions

   • createAsyncThunk：接受一个动作类型字符串和一个返回承诺的函数，并生成一个pending/fulfilled/rejected基于该承诺分派动作类型的thunk。

二、RTK的简单使用

1. 安装 toolkit 和 react-redux

   npm install @reduxjs/toolkit react-redux
   

2. 利用 createSlice 构建store分片（store/features/counter.js）

   import { createSlice } from "@reduxjs/toolkit";
   
   // createSlice(用户标记slice的名称， )
   const counterSlice = createSlice({
     name: "counter",
     initialState: {
       counter: 989,
     },
     reducers: {
       addNumber(state, {payload}) {
         console.log("add number", payload);
         state.counter = state.counter + payload;
       },
       subNumber(state, {payload}) {
         console.log("sub number", payload);
         state.counter = state.counter - payload;
       },
     },
   });
   
   export const { addNumber, subNumber } = counterSlice.actions;
   
   export default counterSlice.reducer;
   
   

3. 利用configureStore 配置store（store/index.js）

   import { configureStore } from "@reduxjs/toolkit";
   
   import counterReducer from "./features/counter";
   
   const store = configureStore({
     reducer: {
       counter: counterReducer,
     },
   });
   
   export default store;
   
   

4. 利用react-redux，依照往常的做法，将store注入index.js

   import React from "react";
   import ReactDOM from "react-dom/client";
   import { Provider } from "react-redux";
   import App from "./App";
   import store from "./store";
   
   const root = ReactDOM.createRoot(document.getElementById("root"));
   root.render(
     // <React.StrictMode>
     <Provider store={store}>
       <App />
     </Provider>
     // </React.StrictMode>
   );
   
   

5. 利用react-redux，依照往常的做法，在需要使用store及dispatch操作的页面文件中通过connect进行连接

   // Home.jsx
   import React, { PureComponent } from "react";
   import { connect } from "react-redux";
   import { addNumber } from "../store/features/counter";
   
   export class Home extends PureComponent {
     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));
     },
   });
   
   export default connect(mapStateToProps, mapDispatchToProps)(Home);
   
   

   // Profile.jsx
   import React, { PureComponent } from "react";
   import { connect } from "react-redux";
   import { subNumber } from "../store/features/counter";
   
   export class Profile extends PureComponent {
     subNumber(num) {
       this.props.subNumber(num);
     }
   
     render() {
       const { counter } = this.props;
       return (
         <div>
           profile:{counter}
           <button onClick={(e) => this.subNumber(5)}>-5</button>
           <button onClick={(e) => this.subNumber(8)}>-8</button>
         </div>
       );
     }
   }
   
   const mapStateToProps = (state) => ({
     counter: state.counter.counter,
   });
   
   const mapDispatchToProps = (dispatch) => ({
     subNumber(num) {
       dispatch(subNumber(num));
     },
   });
   
   export default connect(mapStateToProps, mapDispatchToProps)(Profile);
   
   

6. 将界面引入App.jsx

   import React, { PureComponent } from "react";
   import { connect } from "react-redux";
   import Home from "./pages/Home";
   import Profile from "./pages/Profile";
   import "./style.css";
   
   export class App extends PureComponent {
     render() {
       const { counter } = this.props;
   
       return (
         <div>
           <h2>App Counter: {counter}</h2>
           <div className="pages">
             <Home />
             <Profile />
           </div>
         </div>
       );
     }
   }
   
   const mapStateToProps = (state) => ({
     counter: state.counter.counter
   });
   
   export default connect(mapStateToProps)(App);
   
   

7. 查看运行结果，和之前单独使用react-redux的效果一致，但在代码层面上化繁为简