30-seconds-of-code/snippets/intersection.md

title, tags, expertise, cover, firstSeen, lastUpdated

title	tags	expertise	cover	firstSeen	lastUpdated
Array intersection	array	intermediate	blog_images/red-berries.jpg	2017-12-17T16:41:31+02:00	2020-10-20T23:02:01+03:00

Returns the elements that exist in both arrays, filtering duplicate values.

• Create a Set from b, then use Array.prototype.filter() on a to only keep values contained in b.

const intersection = (a, b) => {
  const s = new Set(b);
  return [...new Set(a)].filter(x => s.has(x));
};

intersection([1, 2, 3], [4, 3, 2]); // [2, 3]