/**
 * The only aim of this file is to make ts-jest happy, as it does not support
 * Object.groupBy and Map.groupBy at the current version (29.1.2)
 *  This is a workaround to make it work.
 */

interface ObjectConstructor {
  /**
   * Groups members of an iterable according to the return value of the passed callback.
   * @param items An iterable.
   * @param keySelector A callback which will be invoked for each item in items.
   */
  groupBy<K extends PropertyKey, T>(
    items: Iterable<T>,
    keySelector: (item: T, index: number) => K
  ): Partial<Record<K, T[]>>;
}

interface MapConstructor {
  /**
   * Groups members of an iterable according to the return value of the passed callback.
   * @param items An iterable.
   * @param keySelector A callback which will be invoked for each item in items.
   */
  groupBy<K, T>(items: Iterable<T>, keySelector: (item: T, index: number) => K): Map<K, T[]>;
}