React状态管理——react-redux
目录
一、redux介绍
二、安装
三、基本实现步骤
3.1 创建Action Types
3.2 创建counterAction
3.3 创建counterReducer
3.4 结合所有Reducer
3.5 创建store
3.6 入口文件中提供store
3.7 在组件中的使用
3.8 使用thunk实现异步支持
3.8.1 安装
3.8.2 在counterAction中添加异步操作
3.8.3 在store文件中添加异步支持
3.8.4 在组件中进行异步操作
3.9 函数式组件使用hooks代替connect
一、redux介绍
Redux 基于三个基本原则：
-
单一数据源：整个应用的状态存储在一个对象树中
-
状态是只读的：唯一改变状态的方法是触发 action
-
使用纯函数执行修改：reducer 是纯函数，接收旧 state 和 action，返回新 state
二、安装
npm install redux react-redux三、基本实现步骤
3.1 创建Action Types
// actionTypes.js
export const INCREMENT = "INCREMENT";
export const DECREMENT = "DECREMENT";
3.2 创建counterAction
// store/actions/counterAction.js
import { INCREMENT, DECREMENT } from "../../utils/actionTypes";
export const increment = () => ({
type: INCREMENT,
});
export const decrement = () => ({
type: DECREMENT,
});
3.3 创建counterReducer
// store/reducers/counterReducer.js
import { INCREMENT, DECREMENT } from "../../utils/actionTypes";
const initialState = {
count: 0,
};
export default function counterReducer(state = initialState, action) {
switch (action.type) {
case INCREMENT:
return { ...state, count: state.count + 1 };
case DECREMENT:
return { ...state, count: state.count - 1 };
default:
return state;
}
}
3.4 结合所有Reducer
// store/reducers/index.js
import { combineReducers } from "redux";
import counterReducer from "./counterReducer";
export default combineReducers({
counter: counterReducer,
});
3.5 创建store
// store/index.js
import { createStore } from "redux";
import reducers from "./reducers";
const store = createStore(reducers);
export default store;
3.6 入口文件中提供store
// index.js
import React from "react";
import ReactDOM from "react-dom/client";
import App from "./App";
import store from "./store";
import { Provider } from "react-redux";
const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(
);
3.7 在组件中的使用
import React from "react";
import { connect } from "react-redux";
import { increment, decrement } from "./store/actions/counterAction";
function App(props) {
const { count, increment, decrement } = props;
return (
数值：{count}
);
}
const mapStateToProps = (state) => ({
count: state.counter.count, // store/reducers/index.js中的counter映射
});
const mapDispatchToProps = {
increment,
decrement,
};
export default connect(mapStateToProps, mapDispatchToProps)(App);
3.8 使用thunk实现异步支持
3.8.1 安装
npm install redux-thunk3.8.2 在counterAction中添加异步操作
// store/actions/counterAction.js
import { INCREMENT, DECREMENT } from "../../utils/actionTypes";
export const increment = () => ({
type: INCREMENT,
});
export const decrement = () => ({
type: DECREMENT,
});
export const fetchIncrement = (timeout) => {
return (dispatch) => {
setTimeout(() => {
dispatch(increment());
}, timeout);
};
};
3.8.3 在store文件中添加异步支持
// store.js
import { createStore, applyMiddleware } from "redux";
import { thunk } from "redux-thunk";
import reducers from "./reducers";
const store = createStore(reducers, applyMiddleware(thunk));
export default store;
3.8.4 在组件中进行异步操作
import React from "react";
import { connect } from "react-redux";
import {
increment,
decrement,
fetchIncrement,
} from "./store/actions/counterAction";
function App(props) {
const { count, increment, decrement, fetchIncrement } = props;
return (
数值：{count}
);
}
const mapStateToProps = (state) => ({
count: state.counter.count, // store/reducers/index.js中的counter映射
});
const mapDispatchToProps = {
increment,
decrement,
fetchIncrement,
};
export default connect(mapStateToProps, mapDispatchToProps)(App);
3.9 函数式组件使用hooks代替connect
// App.js
import React from "react";
import { useSelector, useDispatch } from "react-redux";
import {
increment,
decrement,
fetchIncrement,
} from "./store/actions/counterAction";
export default function App(props) {
const { count } = useSelector((state) => state.counter); // store/reducers/index.js中的counter映射
const dispatch = useDispatch();
return (
数值：{count}
);
}