自己动手实现一个react-redux
之前试过自己动手实现一个redux，这篇blog主要记录动手实现一个react-redux的过程。
这个react-redux还有一点点小瑕疵，我以一个计数器作为例子来实现的。
这是目录结构:
这里的connect.js文件就是react-redux。
├─component
│ connect.js
│ counter.js
│
└─store
index.js
index.js：
import React from "react";
import ReactDom,{render} from "react-dom";
import Couter from "./component/counter";
import {Provider} from "./component/connect"
import store from "./store/index"
ReactDom.render(<Provider store={store}><Couter/></Provider>,document.getElementById("root"));
./store/index.js:
import {createStore} from "redux";
function reducer(state={number:0},action) {
switch (action.type){
case "add":
return {number:state.number+action.count}
default:
return state;
}
}
export default createStore(reducer);
./component/connect.js:
import React from "react";
import PropTypes from "prop-types";
//Provider是一个组件 接受一个store属性 将其内容挂载在上下文context //这样后代才可以都有办法拿到 class Provider extends React.Component{
static childContextTypes={
//设置上下文的类型是对象
store:PropTypes.object
}
getChildContext(){
//获取并设置后代上下文的内容
return {store:this.props.store}
}
render(){
return this.props.children
}
}
let connect=(mapStateToProps,mapDispatchToProps)=>(comp)=>{
return class Proxy extends React.Component{
static contextTypes={
store:PropTypes.object
}
constructor(props,context){
super(props);
//将参数mapStateToProps 的解构赋值 代理组件的状态
this.setState=mapStateToProps(context.store.getState())
}
componentDidMount(){
this.context.store.subscribe(()=>{
this.setState(mapStateToProps(this.context.store.getState()))
})
}
render(){
return <comp {...this.state} {...mapDispatchToProps(this.context.store.dispatch)}/>
}
}
}
export {Provider,connect}
./component/counter.js:
import React from "react";
import {connect} from "./connect";
export default class Counter extends React.Component{
constructor(props){
super(props);
}
render(){
return (
<div>
<button onClick={()=>{
this.props.add(5);
}}>+</button>
{this.props.n}
</div>
)
}
}
let mapStateToProps=(state)=>{
return {n:state.number}
};
let mapDispatchToProps=(dispatch)=>{
return {
add:(count)=>{
dispatch({type:"add",count:count})
}
}
}
export default connect(mapStateToProps,mapDispatchToProps)(Counter)
