export declare type SubscriberFn<T> = (newVal: T, oldVal: T) => void;
export declare class Observable<T> {
    private _val;
    private _subs;
    get val(): T;
    set val(value: T);
    constructor(initialValue: T);
    subscribe(fn: SubscriberFn<T>): () => void;
}
export declare function createObservable<T>(initialValue: T): Observable<T>;