You can use `useAuthenticator` composable to access current signed in `user`. If no user is authenticated, it'll return `undefined`.

```html{1,5-8}
<script setup>
  import { Authenticator, useAuthenticator } from '@aws-amplify/ui-vue';
  const auth = useAuthenticator();
</script>

<template>
  <authenticator></authenticator>
  <template v-if="auth.route === 'authenticated'">
    <h1>Hello {{ auth.user?.username }}!</h1>
    <button @click="auth.signOut">Sign out</button>
  </template>
</template>
```
