import { Observable } from 'rxjs';
import * as i0 from "@angular/core";
export declare class VerticalNavGroupService {
    private _expandChange;
    get expandChange(): Observable<boolean>;
    expand(): void;
    static ɵfac: i0.ɵɵFactoryDeclaration<VerticalNavGroupService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<VerticalNavGroupService>;
}