import { CreateSignalOptions, WritableSignal } from '@angular/core';
import { WritableSygnal } from '../sygnals/sygnal';
export interface Memento {
    /**
     * Restore the signal to the state it was in when the memento was created.
     */
    restore(): void;
}
interface WithMemento {
    /**
     * Create a memento object.
     */
    memento(): Memento;
}
export declare function withMemento<T>(original: WritableSygnal<T>): WritableSygnal<T> & WithMemento;
export declare function withMemento<T>(original: WritableSignal<T>): WritableSignal<T> & WithMemento;
export declare const memento: <T>(initialValue: T, options?: CreateSignalOptions<T> | undefined) => WritableSygnal<T> & WithMemento;
export {};