/**
 * Implementation of some functions of Set Theory
 * See: https://en.wikipedia.org/wiki/Set_theory
 */

// /**
//  * Calculate the complement set.
//  * See Complement (set theory) https://en.wikipedia.org/wiki/Complement_(set_theory)
//  * @param {any[]} universe The universe of available values
//  * @param {any[]} set A subset from the universe.
//  * @returns {any[]} The complementary set of A given the universe
//  */
export function complement(universe: any[], set: any[]): any[] {
  return universe.filter(el => !set.find(_el => el === _el));
}

// /**
//  * Calculate intersection between two sets.
//  * See https://en.wikipedia.org/wiki/Intersection_(set_theory)
//  * @param {any[]} setA The set A
//  * @param {any[]} setB The set B
//  * @returns {any[]} The intersection between A and B
//  */
export function intersection(setA: any[], setB: any[]): any[] {
  return setA.filter(
    aElement => setB.find(bElement => bElement === aElement) !== undefined
  );
}

// /**
//  * Test whether one set is a subset from another
//  * @param subSet The set that must be a subset to return true
//  * @param superSet The set that must contain the subset to return true
//  * @returns {boolean} True if all elements of subset are in superset, false otherwise
//  */
export function testSubset(subSet: any[], superSet: any[]): boolean {
  return subSet.reduce(
    (acc: boolean, el: any) => acc && superSet.indexOf(el) !== -1,
    true
  );
}