import type { Contact, ContactsServiceOptions, Unsubscribe, UpdateContactParams } from '../types';
export declare class ContactsService {
    private _data;
    private _eventName;
    private _subscribers;
    private _contactOptions;
    private _subscribeOptions;
    constructor(options?: ContactsServiceOptions);
    private _findIndex;
    private _publish;
    subscribe(callback: (contacts: Contact[]) => void): Unsubscribe;
    addContact(): Contact;
    updateContact(id: string, params: UpdateContactParams): string;
    deleteContact(id: string): string;
}