您可以在模板中添加以下内容:
<ng-container *ngIf="$loaded | async; else loading">
<ng-container *ngIf="$user | async; else login">
// redirect to home page
</ng-container>
<ng-template #login>
// display login form
</ng-template>
</ng-container>
<ng-template #loading>
// loading
</ng-template>
$loaded = this.$user.pipe(
mapTo(true),
startWith(false)
);