import { AggregateDescriptor } from './aggregate.operators';
import { AggregateResult } from '../transducers';

// tslint:disable:max-line-length
/**
 * The group descriptor used by the `groupBy` method.
 */
export interface GroupDescriptor {
    /**
     * The data item field by which the data will be grouped.
     */
    field: string;
    /**
     * The sort order of the group.
     */
    dir?: 'asc' | 'desc';
    /**
     * The aggregates which are calculated during grouping.
     */
    aggregates?: Array<AggregateDescriptor>;
}

/**
 * The result of the group operation.
 */
export interface GroupResult<T = Object> {
    /**
     * Contains either the subgroups, or the data items.
     */
    items: T[] | GroupResult<T>[];
    /**
     * The aggregated values for the group. An [`AggregateResult`]({% slug api_kendo-data-query_aggregateresult %}) instance.
     */
    aggregates: AggregateResult;
    /**
     * The field by which the data items are grouped.
     */
    field: string;
    /**
     * The group key.
     */
    value: any;
}
// tslint:enable:max-line-length