Why calling detectChanges() inside component doesn't update values, but wrapping code in setTimeout() does it?

Question

I\'m trying to automatically select the first value from set of options in

export class ExampleComponent implements OnI         


        

Answer 1

this.cdr.detectChanges() only runs change detection for the current component (and descendants). If setFirstItemActive() causes changes elsewhere this is not covered. setTimeout() or zone.run(...) or ApplicationRef.tick() causes change detection to be run for the whole application and therefore every binding is covered, not only the current component.