import { EnumerableFactory } from '../utilities/EnumerableFactory';
import { IEnumerable } from '../types';
import { IGrouping } from '../types';
import { EqualityComparer } from '../types';
import { applyGroupBy } from './applicators/applyGroupBy';

export function groupBy<TSource, TKey>(
  src: Iterable<TSource>,
  keySelector: (item: TSource) => TKey,
  equalityComparer?: EqualityComparer<TKey>
): IEnumerable<IGrouping<TKey, TSource>> {
  const factory = new EnumerableFactory();
  return applyGroupBy(factory, src, keySelector, equalityComparer);
}