import { OperatorFunction } from "rxjs";
export declare function instanceOf<T, R extends T>(ctor: new (...args: any[]) => R): OperatorFunction<T, R>;
export declare function instanceOf<T, R extends {
    [key: string]: new (...args: any[]) => T;
}>(ctors: R): OperatorFunction<T, InstanceType<R[keyof R]>>;