core-module.ts

@NgModule({
  imports: [
    ...
  ],
  declarations: [
    ...
  ],
  exports: [
    ...
  ],
})
export class CoreModule {
  public static forRoot(): ModuleWithProviders<CoreModule> {
    return {
      ngModule: CoreModule,
      providers: [
        {
          provide: ROUTER_SCROLL_SERVICE,
          useClass: RouterScrollServiceImpl,
        },
      ],
    };
  }
}