declare global {
    interface Array<T> {
        first(this: T[]): T | undefined;
        last(this: T[]): T | undefined;
        elementAt(this: T[], index: number): T | undefined;
        distinct(this: T[]): T[];
        distinctBy<TKey>(this: T[], property: (item: T) => TKey): T[];
        contains(this: T[], item: T): boolean;
        orderBy(this: T[], ...properties: ((item: T) => any)[]): T[];
        orderByDesc(this: T[], property: (item: T) => any): T[];
        move(this: T[], from: number, to: number): T[];
        groupBy<TKey>(this: T[], property: (item: T) => TKey): Group<TKey, T>[];
    }
}
export declare function first<T>(this: T[]): T | undefined;
export declare function last<T>(this: T[]): T | undefined;
export declare function elementAt<T>(this: T[], index: number): T | undefined;
/**
 * Removes duplicates from a collection based on a Set
 *
 * @param this Array
 * @returns Array
 */
export declare function distinct<T>(this: T[]): T[];
/**
 * Removes duplicates from a collection based on a Set
 *
 * @param this Array
 * @returns Array
 */
export declare function distinctBy<T, TKey>(this: T[], property: (item: T) => TKey): T[];
export declare function contains<T>(this: T[], item: T): boolean;
export declare function flatten<T>(array: T[], nestedArrayFunc: (item: T) => T[]): T[];
/**
 * Sorts array by specified properties based on "lodashOrderBy" function
 *
 * @param this Array
 * @param properties List of property selectors
 * @returns Sorted array
 */
export declare function orderBy<T>(this: T[], ...properties: ((item: T) => any)[]): T[];
export declare function orderByDesc<T>(this: T[], property: (item: T) => any): T[];
export declare function move<T>(this: T[], from: number, to: number): T[];
export declare function groupBy<T, TKey>(this: T[], property: (item: T) => TKey): Group<TKey, T>[];