/**
 * Calculate a set difference between two arrays
 *
 * @returns an array with elements from the first array that are not present in the second array
 */
export declare function difference<T>(a: T[], b: T[]): T[];
/**
 * Calculate a set union of two arrays.
 *
 * If there are non-unique elements in either array, they will be lost.
 *
 * @returns an array with all unique elements from two source arrays
 */
export declare function union<T>(a: T[], b: T[]): T[];