export declare function pickBy<T extends { [s: string]: T[keyof T]; } | ArrayLike<T[keyof T]>>(obj: T, fn: (i: T[keyof T]) => boolean): Partial<T>; export declare function maxBy<T>(arr: T[], fn: (i: T) => number): T | undefined; type SortTypes = string | number | undefined | boolean; export declare function sortBy<T>(arr: T[], fn: (i: T) => SortTypes | SortTypes[]): T[]; export {};