import { IterableX } from '../iterablex';
import { MonoTypeOperatorFunction } from '../../interfaces';
export declare class DefaultIfEmptyIterable<TSource> extends IterableX<TSource> {
    private _source;
    private _defaultValue;
    constructor(source: Iterable<TSource>, defaultValue: TSource);
    [Symbol.iterator](): Generator<TSource, void, unknown>;
}
export declare function defaultIfEmpty<T>(defaultValue: T): MonoTypeOperatorFunction<T>;