import { DeepMap } from './deepMap';
export type GroupKeyType<T extends any = any> = T;
export type GroupBy<DataType, KeyType> = {
    field: keyof DataType & string;
    toKey?: (value: any, data: DataType) => GroupKeyType<KeyType>;
};
export type AggregateParams<DataType, KeyType> = {
    reducers: Record<string, DataAggregationReducer<DataType, any>>;
    groupBy?: GroupBy<DataType, KeyType>[];
    defaultToKey?: (value: any, item: DataType) => GroupKeyType<KeyType>;
};
export type DataAggregationReducer<T, AggregationResultType> = {
    name?: string;
    field?: keyof T & string;
    initialValue?: AggregationResultType;
    getter?: (data: T) => any;
    reducer: string | ((accumulator: any, value: any, data: T, dataIndex: number) => AggregationResultType | any);
    done?: (accumulatedValue: AggregationResultType | any, array: T[]) => AggregationResultType;
};
export type DataAggregationResult<DataType, KeyType extends any> = {
    deepMap: DeepMap<GroupKeyType<KeyType>, DeepMapAggregationValueType<DataType, KeyType>>;
    aggregateParams: AggregateParams<DataType, KeyType>;
    initialData: DataType[];
    reducerResults?: Record<string, AggregationReducerResult>;
};
export type DeepMapAggregationValueType<DataType, KeyType> = {
    items: DataType[];
    commonData?: Partial<DataType>;
    reducerResults: Record<string, AggregationReducerResult>;
};
export type AggregationReducerResult = number;
export declare function aggregate<DataType, KeyType = any>(aggregateParams: AggregateParams<DataType, KeyType>, data: DataType[]): DataAggregationResult<DataType, KeyType>;