/**
 * @module viw-webgl-react
 */
/**
 * Recursive Tree implemented as a recursive map.
 */
export type MapTree<K, V> = Map<K, V[] | MapTree<K, V>>;
/**
 * Returns true if both argument are null or pair-wise equal.
 */
export declare function ArrayEquals<T>(first: T[], second: T[]): boolean;
/**
 * Creates N-level grouping of items using given grouping selector in the order provided.
 * @param items array of items to groups
 * @param grouping array of selectors
 * @returns a Map of Map ... of Map<string, item> with the first map containing a single element called root.
 */
export declare function toMapTree<V>(items: V[], grouping: ((v: V) => string)[]): MapTree<string, V>;
/**
 * groups elements of an array into a map using values returned by selector.
 * Intended to work as Linq.GroupBy
 */
export declare function groupBy<K, V>(array: V[], selector: (o: V) => K): Map<K, V[]>;
/**
 * Takes a N-deep Map tree and reinsert all element in sorted order.
 */
export declare function sort<K, V>(map: MapTree<K, V>): void;
