import { Observable, ObservableInput, ObservableInputTuple, ObservedValueOf, OperatorFunction } from 'rxjs';
import { BuilderState } from '../types';
/**
 * Operator function that projects each source value to an Observable which is merged in the output Observable,
 * only if the source value is a BuilderDone state.
 *
 * The project function is applied to each value emitted by the source Observable. If the source value is a BuilderDone state,
 * the project function is called with the result of the BuilderDone state and the index as arguments, and the returned Observable
 * is merged into the output Observable. If the source value is not a BuilderDone state, it is emitted directly to the output Observable.
 * @param {Function} project - The function to apply to each BuilderDone value emitted by the source Observable.
 * @returns {OperatorFunction} - An OperatorFunction that emits the items from the source Observable or the projected Observables.
 */
export declare function whenDone<T, O extends ObservableInput<any>>(project: (value: T, index: number) => ObservableInput<BuilderState<ObservedValueOf<O>>>): OperatorFunction<BuilderState<T>, BuilderState<ObservedValueOf<O>>>;
/**
 *
 * @param tag
 * @param builders
 * @param project
 */
export declare function factoryChain<T, TChild>(tag: string, builders: readonly [...ObservableInputTuple<Array<BuilderState<T>>>], project: (...args: T[]) => readonly [...ObservableInputTuple<Array<BuilderState<TChild>>>]): Observable<BuilderState<TChild>>;