/**
 * Returns the last element of an array.
 * @param array The array.
 * @param n Which element from the end (default is zero).
 */
export declare function tail<T>(array: ArrayLike<T>, n?: number): T;
export declare function tail2<T>(arr: T[]): [T[], T];
export declare function equals<T>(one: ReadonlyArray<T> | undefined, other: ReadonlyArray<T> | undefined, itemEquals?: (a: T, b: T) => boolean): boolean;
export declare function binarySearch<T>(array: ReadonlyArray<T>, key: T, comparator: (op1: T, op2: T) => number): number;