pl2.ts

@Injectable({ providedIn: 'root' })
export class AppPreloadingStrategy implements PreloadingStrategy {
  constructor(private userQuery: UserQuery) {
  }

  preload(route: Route, load: () => Observable<any>): Observable<any> {
    return this.userQuery.hasFlags(route.data.flags) ? load() : of(false);
  }
}

pl3.ts

const routes: Routes = [
  {
    path: 'bar',
    loadChildren: () => import('./bar/bar.module').then(m => m.BarModule),
    data: {
      flags: 'a'
    },
  }
];

@NgModule({
  imports: [RouterModule.forRoot(routes, { preloadingStrategy: AppPreloadingStrategy })],
  exports: [RouterModule]
})
export class AppRoutingModule {
}