export declare function toMap<TSource, TKey>(source: Iterable<TSource>, keySelector: (item: TSource) => TKey): Map<TKey, TSource>;
export declare function toMap<TSource, TKey, TElement = TSource>(source: Iterable<TSource>, keySelector: (item: TSource) => TKey, elementSelector?: (item: TSource) => TElement): Map<TKey, TElement>;