arrayComplement and arrayIntersection

_readme.md

array-utils.ts

export function arrayComplement<T, K1 extends keyof T>(
  a: T[],
  key: K1,
  b: T[K1][]
) {
  const setB = new Set(b.map((item) => item));
  return a.filter((item) => !setB.has(item[key]));
}

export function arrayIntersection<T, K1 extends keyof T>(
  a: T[],
  key: K1,
  b: T[K1][]
) {
  const setB = new Set(b.map((item) => item));
  return a.filter((item) => setB.has(item[key]));
}