简单介绍下项目背景，我这里做了一个demo，前端使用mock数据，然后实现简单的路由拦截，校验session是否包含用户作为已登录的依据，react-router-dom是v6。不像vue可以设置登录拦截beforeenter，react需要我们自己加。

//router.js
import React, { lazy } from "react";
import { Navigate } from 'react-router-dom'const Error = lazy(() => import("@/pages/Error/Error.jsx"))
const Index = lazy(() => import("@/pages/Index/Index.jsx"))
const Login = lazy(() => import("@/pages/Login/Login.jsx"))export const routes = [{path: "/",element: <Navigate to="/index"/>},{path: "/login",element: <Login />},{path: "/index",element: <Index />},{path: "*",element: <Error />},
]

import React, { useEffect, Suspense } from 'react'
import { useRoutes, useNavigate } from 'react-router-dom'
import { routes } from './router'export default function Index() {const element = useRoutes(routes)return (<Authen route={element} children={element.children}><Suspense><div>{element}</div></Suspense></Authen>)}
//实现路由拦截
const Authen = (props) => {const navigate = useNavigate()const { route, children } = propsconst username = sessionStorage.getItem('username')console.log(props);useEffect(() => {if (route.props.match.pathname === "/login" && username) {navigate('/index')}}, [route, navigate,username])return children
}

Surpense组件是react组件懒加载的时候，路由跳转了，由于网络原因，组件内容无法及时过去，不添加会报错。