import { Arr, ArrOrObj, Obj, Fn, ValidMap, List } from '../_typings'

// -----------

export interface Reduced {}

/**
 * Returns a value wrapped to indicate that it is the final value of the reduce and
 * transduce functions. The returned value should be considered a black box: the internal
 * structure is not guaranteed to be stable.
 */
export type reduced<T> = (elem: T) => Reduced

// map iterator -> obj
export declare function reduce(map: ValidMap): Obj
/**
 * Returns a single item by iterating through the list, successively calling the iterator
 * function and passing it an accumulator value and the current value from the array, and
 * then passing the result to the next call.
 */
export declare function reduce<T, TResult, R extends List<T>>(
  fn: (acc: TResult, elem: T, idx: number, list: R) => TResult | Reduced,
  acc: TResult,
  list: R
): TResult
// export declare function reduce<T, TResult, R extends List<T>>(
//   fn: (acc: TResult, elem: T, idx: number, list: R) => TResult | Reduced,
//   acc: TResult
// ): {
//   (list: R): TResult
// }
// export declare function reduce<T, TResult, R extends List<T>>(
//   fn: (acc: TResult, elem: T, idx: number, list: R) => TResult | Reduced
// ): {
//   (acc: TResult, list: R): TResult
//   (acc: TResult): {
//     (list: R): TResult
//   }
// }