Router view cannot be rendered (a very low-level error)

A problem encountered in writing code today ,
router-view It can't be rendered . I checked it carefully , I can't see the problem , After looking carefully for a long time .
It turned out to be a spelling mistake .

In addition, I see other centralized reasons on the Internet , It may lead to unsuccessful rendering
1.to The value of the attribute should be the same as that in the route path Have the same value
2. Import and export

vue-router website ：https://router.vuejs.org/zh/
Official website entry case ：

<script src="https://unpkg.com/[email protected]"></script>
<script src="https://unpkg.com/[email protected]"></script>

<div id="app">
  <h1>Hello App!</h1>
  <p>
    <!-- Use  router-link  Components for navigation  -->
    <!-- By passing  `to`  To specify the link  -->
    <!--`<router-link>`  A with the correct  `href`  Attribute  `<a>`  label -->
    <router-link to="/">Go to Home</router-link>
    <router-link to="/about">Go to About</router-link>
  </p>
  <!--  Route exit  -->
  <!--  The component to which the route matches is rendered here  -->
  <router-view></router-view>
</div>

// 1.  Define routing components .
//  You can also import from other files 
const Home = {
     template: '<div>Home</div>' }
const About = {
     template: '<div>About</div>' }

// 2.  Define some routes 
//  Each route needs to be mapped to a component .
//  We will discuss nested routing later .
const routes = [
  {
     path: '/', component: Home },
  {
     path: '/about', component: About },
]

// 3.  Create a routing instance and pass  `routes`  To configure 
//  You can enter more configurations here , But we're here 
//  Keep it simple for a while 
const router = VueRouter.createRouter({
    
  // 4.  The interior provides  history  The realization of pattern . For the sake of simplicity , We use it here  hash  Pattern .
  history: VueRouter.createWebHashHistory(),
  routes, // `routes: routes`  Abbreviation 
})

// 5.  Create and mount the root instance 
const app = Vue.createApp({
    })
// Make sure  _use_  Routing instance makes 
// The whole application supports routing .
app.use(router)

app.mount('#app')

//  Now? , The app has started ！

Tutorial code given by the official website , For reference only