route-id.ts

export const ROUTE_ID = new InjectionToken<Observable<string>>(
  'Returns an observable in the route id being passed as a parameter',
);

export function routeIdFactory(route: ActivatedRoute): Observable<string> {
    return route.paramMap.pipe(map(params => params.get('id')));
}

export const ROUTE_ID_PROVIDERS: Provider[] = [
    {
        provide: ROUTE_ID,
        deps: [ActivatedRoute],
        useFactory: routeIdFactory,
    },
];