import { Signal, WritableSignal } from "@angular/core";
export declare function $obj<T extends object | undefined>(sig: Signal<T> | WritableSignal<T>): {
    snapshot(): void;
    changed(): boolean;
    readonly origin: T | undefined;
    updateField<K extends keyof T>(key: K, val: T[K]): void;
    deleteField<K extends keyof T>(key: K): void;
};