set operations

set-operations.js

// s1 contains all elements of s2
function setContains(s1, s2) {
  return new Set([...s2].every(x => s1.has(x)));
}

// elements in both s1 and s2
function setIntersection(s1, s2) {
  return new Set([...s1].filter(x => s2.has(x)));
}

// elements only existing in s1
function setDifference(s1, s2) {
  return new Set([...s1].filter(x => !s2.has(x)));
}

function setEqual(s1, s2) {
  return s1.length === s2.length && setContains(s1, s2);
}

module.exports = {
  setContains,
  setIntersection,
  setDifference,
  setEqual,
};