/*
 * Copyright (C) 2022 StApps
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <https://www.gnu.org/licenses/>.
 */

/**
 * Returns the difference between two arrays.
 */
export function differenceBy<T>(a: T[], b: T[], transform: (item: T) => unknown) {
  const disallowed = new Set(b.map(transform));

  return a.filter(item => !disallowed.has(transform(item)));
}