export declare namespace $array {
    function upsert<T>(arr: T[], x: T, matcher: (x: T) => boolean, opts?: {
        patch: boolean;
    }): T[];
    function equal<T>(a: T[], b: T[]): boolean;
    function remove<T>(arr: T[], matcher: (x: T) => boolean): T[];
    function remove<T>(arr: T[], item: T): T[];
    function replace<T>(arr: T[], item: T, matcher: (x: T, item: T, i: number) => boolean): void;
    function shuffle<T>(arr: T[]): T[];
    function trimEnd<T>(arr: T[]): T[];
    function findIndex<T>(array: T[], matcher: (item: T, i?: number) => boolean, fromIdx?: number): number;
}