import type { Comparer } from '../../types/Comparer.js';
declare global {
    interface ReadonlyArray<T> {
        /**
         * Finds matching elements between two arrays.
         *
         * @param other - The other array to union with.
         * @param comparerFn - An optional function that accepts two arguments.
         *  The union method calls the comparerFn function to determine the
         *  equality of values. Triple equal `===` comparison is used by default.
         *
         * @returns A new array containing only the matching elements.
         */
        union(other: readonly T[], comparerFn?: Comparer<T>): T[];
    }
    interface Array<T> {
        /**
         * Finds matching elements between two arrays.
         *
         * @param other - The other array to union with.
         * @param comparerFn - An optional function that accepts two arguments.
         *  The union method calls the comparerFn function to determine the
         *  equality of values. Triple equal `===` comparison is used by default.
         *
         * @returns A new array containing only the matching elements.
         */
        union(other: readonly T[], comparerFn?: Comparer<T>): T[];
    }
}