Observing @Output Event Emitters in Child Components?

How should be go about using / observing parent @Output() event emitters in child components?

For example in this demo the child component uses the @Output onGreetingChange like this:

<app-greeting [greeting]="onGreetingChange | async"></app-greeting>


And this will work if onGreetingChange emits in the AfterViewInit life cycle hook.

ngAfterViewInit() {
this.onGreetingChange.emit('Hola');
}


However that produces the an ExpressionChangedAfterItHasBeenCheckedError error.

Is there a way to get to this to work without producing the error?

I tried emitting in both the constructor and OnInit. Thoughts?

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