@reactivex/ix-esnext-esm/asynciterable/extremaoptions.d.ts

export interface ExtremaOptions<TSource, TKey> {
    selector?: (item: TSource, signal?: AbortSignal) => TKey | Promise<TKey>;
    comparer?: (left: TKey, right: TKey) => number | Promise<number>;
    signal?: AbortSignal;
}