* ngFor循环使用异步管道？

Question

Reading through this article and it has an ngFor loop like this:

*ngFor="let contact of contacts | async"

How does the async pipe work in this context?

Answer 1

The async pipe gives the latest value from an observable. In this case (as in other cases) it will refresh the data involved when a new value comes down the observable. So if the screen renders and the observable updates the ngFor will re-render.