import { ObjOrArrBaseBy, ObjValues, AnyObjOrArr, AnyArr } from '../typings/types';
interface GroupBy {
    <Fn extends ObjOrArrBaseBy<AnyObjOrArr, any>>(fn: Fn): <Input extends AnyObjOrArr>(obj: Input) => Input extends AnyArr ? Record<ReturnType<Fn>, Input> : Record<ReturnType<Fn>, ObjValues<Input>[]>;
    <Input extends AnyObjOrArr, Fn extends ObjOrArrBaseBy<Input, any>>(fn: Fn, obj: Input): Input extends AnyArr ? Record<ReturnType<Fn>, Input> : Record<ReturnType<Fn>, ObjValues<Input>[]>;
}
/**
 * Creates an object composed of keys generated from the results of running
 * each element of object thru `fn`. The corresponding
 * value of each key is an array of elements responsible for generating the key.
 *
 * @param {Function} fn The function to transform value to group key. Receives three argument, `value`, `key`, `obj`.
 * @param {Object} obj The obj to iterate over.
 * @returns {Object} Returns the composed aggregate object.
 * @example
 *
 * groupBy(x => x, { a: 1, b: 1, c: 3});// => { '1': [1, 1], '3': [3] }
 */
declare const _default: GroupBy;
export default _default;