RootComponent.vue

<template>
  <Suspense>
    <template #default>
      <async-component />
    </template>
    <template #fallback>
      Loading component....
    </template>
  </Suspense>
</template>

<script>
import AsyncComponent from "./AsyncComponent.vue";
export default {
  name: 'RootComponent',
  components: {AsyncComponent},
}
</script>