Which @angular/* package(s) are relevant/related to the feature request?

core

Description

When developing with NgModules we were able to do:

const moduleRef = await platformBrowserDynamic().bootstrapModule(AppModule);
moduleRef.onDestroy(() => { /* some logic */ });

The new bootstrapApplication now returns a ApplicationRef. Although the onDestroy method exists in ApplicationRef, it's marked as internal and not exposed.

Proposed solution

Make ApplicationRef.onDestroy not internal and part of the public API. This makes sense as well because .destroy() and .destroyed are part of the public API.

Alternatives considered

(applicationRef as any).onDestroy(() => {});

or getting the reference to the first component and using its onDestroy.