import React from "react";import {BrowserRouter as Router, Switch, Route, Link} from "react-router-dom";const routes = [
  {path: "/sandwiches", component: Sandwiches},
                             {path: "/tacos", component: Tacos, routes:
                                                                 [{ path: "/tacos/bus", component: Bus},
                                                                                                                                    { path: "/tacos/cart", component: Cart}]}];export default function RouteConfigExample() {
  return (
    <Router>
      <div>
        <ul><li><Link to="/tacos">Tacos</Link></li>
                <li><Link to="/sandwiches">Sandwiches</Link></li></ul>
        <Switch>
            {routes.map((route, i) => (<RouteWithSubRoutes key={i} {...route} />))}
        </Switch>
      </div>
    </Router>
  );}function RouteWithSubRoutes(route) {
  return (
    <Route path={route.path}
                render={props => (  // pass the sub-routes down to keep nesting
                                <route.component {...props} routes={route.routes} />)} />
  );}function Sandwiches() {return <h2>Sandwiches</h2>;}function Tacos({ routes }) {
  return (
    <div>
      <h2>Tacos</h2>
      <ul><li><Link to="/tacos/bus">Bus</Link></li>
             <li><Link to="/tacos/cart">Cart</Link></li>
      </ul>
      <Switch>
          {routes.map((route, i) => (<RouteWithSubRoutes key={i} {...route} />))}
      </Switch>
    </div>
  );}function Bus() {return <h3>Bus</h3>;}function Cart() {return <h3>Cart</h3>;}