redux reported an error TypeError: Cannot read property "state" of undefined

reducer

import axios from "axios"

const REGISTER_SUCCESS="REGISTER_SUCCESS"
const LOGIN_SUCCESS="LOGIN_SUCCESS"
const ERROR_MSG="ERROR_MSG"
const initial={
    username:"",
    pwd:"",
    msg:""
}
export default function user(state=initial,action){
    switch(action.type){
        case REGISTER_SUCCESS:
            return {...state,...action.payload}
        case ERROR_MSG:
            return {...state,msg:action.msg}
        default:
            return state
    }
}

function Success(payload){
    return{type:"REGISTER_SUCCESS",payload:payload}
}
function Error_Msg(msg){
    return{type:"ERROR_MSG",msg:msg}
}
export function regisger({username,pwd,repwd}){//
    if(!username||!pwd){
        return Error_Msg("")
    }
    if(pwd!==repwd){
        return Error_Msg("")
    }
    return dispatch=>{
        axios.post("/register",{username,pwd})
        .then(res=>{
            if(res.status==200&&res.data.code==1){
                dispatch(Success({username,pwd}))
            }else{
                dispatch(Error_Msg(res.data.msg))
            }
        })
    }
}

component:

import React from "react"
import ReactDOM from "react-dom"
import {connect} from "react-redux"
import  "./register.css"
import {regisger} from "../../redux/user_redux"
class Register extends React.Component{
    constructor(){
        super();
        this.state={
            username:"",
            pwd:"",
            repwd:""
        }
    }
    handleClick(){
        this.props.regisger(this.state)
        console.log(this.props);
    }
    handleChange(key,val){
        this.setState({
            [key]:val
        })
    }
    render(){
        return (
                <form className="register">
                    <div id="form">
                        <div className="input-area">
                            <div className="input-label">
                                <label htmlFor="username"></label>
                            </div>
                            <div className="input-outer">
                                <input type="text" id="username" name="username" onChange={v=>this.handleChange("username",v.target.value)}/>
                            </div>

                            <p className="input-error">

                        </div>

                        <div className="input-area">
                            <div className="input-label">
                                <label htmlFor="password"></label>
                            </div>
                            <div className="input-outer">
                                <input type="password" id="password" name="password" onChange={v=>this.handleChange("pwd",v.target.value)}/>
                            </div>

                            <p className="input-error">1111

                        </div>
                
                        <div className="input-area">
                            <div className="input-label">
                                <label htmlFor="repassword"></label>
                            </div>
                            <div className="input-outer">
                                <input type="password" id="repassword" name="repassword" onChange={v=>this.handleChange("repwd",v.target.value)}/>
                            </div>

                            <p className="input-error">1111

                        </div>

                        <div className="input-area">
                            <input type="button" value="" onClick={this.handleClick.bind(this)}/>
                        </div>
                    </div>
                </form>
            
        )
    }
}
export default connect(
    state=>state,
    {regisger}
)(Register)

index.js

import React from "react"
import ReactDOM from "react-dom"
import { createStore, applyMiddleware, compose } from "redux"
import thunk from "redux-thunk"
import {Provider} from "react-redux"
import {BrowserRouter,Route,Switch} from "react-router-dom"

import Register from "./component/register/register"
import Login from "./component/login/login"
import Home from "./component/home/home"
import "./index.css"
import reducers from "./redux/user_redux.js"
const store = createStore(reducers, compose(
    applyMiddleware(thunk),
    window.devToolsExtension?window.devToolsExtension():f=>f
))

ReactDOM.render(
    (<Provider store={store}>
        <BrowserRouter>
            <Switch>
                <Route path="/" exact component={Home}></Route>
                <Route path="/register" component={Register}></Route>
                <Route path="/login" component={Login}></Route>
            </Switch>
        </BrowserRouter>
    </Provider>),
    document.getElementById("root")
);