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

title, tags, expertise, author, cover, firstSeen, lastUpdated

title	tags	expertise	author	cover	firstSeen	lastUpdated
Check if arrays have same contents	array	intermediate	chalarangelo	blog_images/interior-15.jpg	2020-01-05T21:40:39+02:00	2020-10-19T22:49:51+03:00

Checks if two arrays contain the same elements regardless of order.

• Use a for...of loop over a Set created from the values of both arrays.
• Use Array.prototype.filter() to compare the amount of occurrences of each distinct value in both arrays.
• Return false if the counts do not match for any element, true otherwise.

const haveSameContents = (a, b) => {
  for (const v of new Set([...a, ...b]))
    if (a.filter(e => e === v).length !== b.filter(e => e === v).length)
      return false;
  return true;
};

haveSameContents([1, 2, 4], [2, 4, 1]); // true