import { type ObservableLike, Observable } from "./Observable.js";
/**
 * Selectively keeps values for which the callback returns `true`. All other
 * values are discarded.
 */
export declare function filter<T, S extends T>(callback: ((value: T) => value is S) | ((value: T) => boolean)): (observable: ObservableLike<T>) => Observable<S>;
//# sourceMappingURL=filter.d.ts.map