import { InjectionToken } from '@angular/core' ; export const INTERSECTION_ROOT_MARGIN_DEFAULT = '0px 0px 0px 0px' ; export const INTERSECTION_ROOT_MARGIN = new InjectionToken < string > ( 'rootMargin for IntersectionObserver' , { providedIn : 'root' , factory : ( ) => INTERSECTION_ROOT_MARGIN_DEFAULT , } ) ;