import { AsyncIterableX } from './asynciterablex';
export declare class DefaultIfEmptyAsyncIterable<TSource> extends AsyncIterableX<TSource> {
    private _source;
    private _defaultValue;
    constructor(source: AsyncIterable<TSource>, defaultValue: TSource);
    [Symbol.asyncIterator](): AsyncIterableIterator<TSource>;
}
export declare function defaultIfEmpty<T>(source: AsyncIterable<T>, defaultValue: T): AsyncIterableX<T>;