How to convert Set to Array?

Question

Set seems like a nice way to create Arrays with guaranteed unique elements, but it does not expose any good way to get properties, except for generator [Set].values, which is called in an awkward way of mySet.values.next().

This would have been ok, if you could call map and similar functions on Sets. But you cannot do that, as well.

I've tried Array.from, but seems to be converting only array-like (NodeList and TypedArrays ?) objects to Array. Another try: Object.keys does not work for Sets, and Set.prototype does not have similar static method.

So, the question: Is there any convenient inbuilt method for creating an Array with values of a given Set ? (Order of element does not really matter).

if no such option exists, then maybe there is a nice idiomatic one-liner for doing that ? like, using for...of, or similar ?

Answer 1

if no such option exists, then maybe there is a nice idiomatic one-liner for doing that ? like, using for...of, or similar ?

Indeed, there are several ways to convert a Set to an Array:

• Using Array.from:

Note: safer for TypeScript.

const array = Array.from(mySet);

• Simply spreading the Set out in an array:

Note: Spreading a Set has issues when compiled with TypeScript (See issue #8856). It's safer to use Array.from above instead.

const array = [...mySet];

• The old-fashioned way, iterating and pushing to a new array (Sets do have forEach):

const array = [];
mySet.forEach(v => array.push(v));

• Previously, using the non-standard, and now deprecated array comprehension syntax:

const array = [v for (v of mySet)];