counter.js

import React from ‘react’ import { connect } from ‘react-redux’ function Counter(props) { console.log(props) return ( <div> {/ 使用dispatch方法传入指令给reducer，指令是一个对象 /} <button onClick={() => { props.dispatch({ type:‘increment’ }) }}>+1 <span>{props.count}</span> <button onClick={() => { props.dispatch({ type:‘decrement’ }) }}>-1</button> </div> ) } const mapStateToProps = state=> ({ count:state.count }) export default connect(mapStateToProps)(Counter)

Counter.reducer.js

const initialState = { count:6 } //state是返回值,action是接收的指令 export default (state = initialState, action) => { switch (action.type) { case ‘increment’: return { count:state.count + 1 } case ‘decrement’: return { count:state.count - 1 } default: return state } }