type GroupByCallback<T, K> = (arg: T) => K;
export declare function mapFirstKey<K>(map: Map<K, any>): K | undefined;
export declare function pushOnArrayAtEntry<K, V>(map: Map<K, V[]>, key: K, newElement: V): void;
export declare function popFromArrayAtEntry<K, V>(map: Map<K, V[]>, key: K, elementToRemove: V, removeFromMapIfEmpty?: boolean): void;
export declare function addToSetAtEntry<K, V>(map: Map<K, Set<V>>, key: K, newElement: V): void;
export declare function addToMapAtEntry<K0, K1, V>(map: Map<K0, Map<K1, V>>, key0: K0, key1: K1, newElement: V): void;
export declare function getMapElementAtEntry<K0, K1, V>(map: Map<K0, Map<K1, V>>, key0: K0, key1: K1): V | undefined;
export declare function mapValuesToArray<K, V>(map: Map<K, V>, target: Array<V>): Array<V>;
export declare function removeFromSetAtEntry<K, V>(map: Map<K, Set<V>>, key: K, elementToRemove: V): void;
export declare function unshiftOnArrayAtEntry<K, V>(map: Map<K, V[]>, key: K, newElement: V): void;
export declare function concatOnArrayAtEntry<K, V>(map: Map<K, V[]>, key: K, newElements: V[]): void;
export declare function mapGroupBy<T, K>(array: readonly T[], callback: GroupByCallback<T, K>): Map<K, T[]>;
export declare function mapIncrementAtEntry<K>(map: Map<K, number>, key: K, initValue: number): number;
export declare function mapEntriesCount<K, V>(map: Map<K, V>): number;
export declare class MapUtils {
    static pushOnArrayAtEntry: typeof pushOnArrayAtEntry;
    static addToSetAtEntry: typeof addToSetAtEntry;
    static popFromArrayAtEntry: typeof popFromArrayAtEntry;
    static removeFromSetAtEntry: typeof removeFromSetAtEntry;
    static unshiftOnArrayAtEntry: typeof unshiftOnArrayAtEntry;
    static concatOnArrayAtEntry: typeof concatOnArrayAtEntry;
    static groupBy: typeof mapGroupBy;
    static incrementAtEntry: typeof mapIncrementAtEntry;
    static firstKey: typeof mapFirstKey;
}
export {};