import { Observable } from '../Observable';
/**
 * Catches errors on the observable to be handled by returning a new observable or throwing an error.
 * @param {function} selector a function that takes as arguments `err`, which is the error, and `caught`, which
 *  is the source observable, in case you'd like to "retry" that observable by returning it again. Whatever observable
 *  is returned by the `selector` will be used to continue the observable chain.
 * @return {Observable} an observable that originates from either the source or the observable returned by the
 *  catch `selector` function.
 */
export declare function _catch<T, R>(selector: (err: any, caught: Observable<T>) => Observable<R>): Observable<R>;