import { Undefinable } from "../Types";
import { IModelState } from "./IModelState";
export default abstract class BaseModelState<T> implements IModelState<T> {
    #private;
    constructor(value?: T);
    /**
     * Creates a subscription to the ModelState that will be called when
     * the state is updated.
     *
     * @param callback The callback to be invoked when the state is updated
     * @returns A symbol that must saved to unsubscribe from the ModelState
     */
    subscribe(postCallback: (value: Undefinable<T>) => void, preCallback?: (value: Undefinable<T>) => void): string;
    /**
     * Unsubscribes a component from the model state.
     *
     * @param key The symbol that was returned from the subscribe method.
     */
    unsubscribe(key: string): void;
    /** Gets the current value of the ModelState */
    get value(): Undefinable<T>;
    /** Returns the current value of the ModelState */
    valueOf(): Undefinable<T>;
    /** Returns the string version of the ModelState value */
    toString(): string;
    /** Returns the ModelState as a Promise */
    toPromise(): Promise<Undefinable<T>>;
    protected subscribeCore(postCallback: (value: Undefinable<T>) => void, preCallback?: (value: Undefinable<T>) => void, publishCurrentValue?: boolean): string;
    protected getValue(): Undefinable<T>;
    protected setValue(value: Undefinable<T>): void;
}