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

title, tags, expertise, cover, firstSeen, lastUpdated

title	tags	expertise	cover	firstSeen	lastUpdated
Array symmetric difference	array,math	intermediate	blog_images/trippy-chemicals.jpg	2017-12-17T17:55:51+02:00	2020-10-22T20:24:30+03:00

Returns the symmetric difference between two arrays, without filtering out duplicate values.

• Create a Set from each array to get the unique values of each one.
• Use Array.prototype.filter() on each of them to only keep values not contained in the other.

const symmetricDifference = (a, b) => {
  const sA = new Set(a),
    sB = new Set(b);
  return [...a.filter(x => !sB.has(x)), ...b.filter(x => !sA.has(x))];
};

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