Function difference

src/utils/set.ts:4–12

(a: Set<A>, b: Set<A>)

 * Note: this code is hot, so is optimized for speed.
 */
export function difference<A>(a: Set<A>, b: Set<A>): Set<A> {
  const result = new Set<A>()
  for (const item of a) {
    if (!b.has(item)) {
      result.add(item)
    }
  }
  return result
}

/**
 * Note: this code is hot, so is optimized for speed.