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

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

title	tags	expertise	author	cover	firstSeen	lastUpdated
Freeze Set object	array	intermediate	maciv	blog_images/frozen-globe.jpg	2020-10-11T11:52:48+03:00	2020-10-11T11:52:48+03:00

Creates a frozen Set object.

• Use the Set constructor to create a new Set object from iterable.
• Set the add, delete and clear methods of the newly created object to undefined, so that they cannot be used, practically freezing the object.

const frozenSet = iterable => {
  const s = new Set(iterable);
  s.add = undefined;
  s.delete = undefined;
  s.clear = undefined;
  return s;
};

frozenSet([1, 2, 3, 1, 2]);
// Set { 1, 2, 3, add: undefined, delete: undefined, clear: undefined }