How to convert Set to Array?

javascript arrays collections syntax ecmascript-harmony
c69 picture c69 · Nov 19, 2013 · Viewed 258.9k times · Source

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

adeneo picture adeneo · Nov 19, 2013

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

let array = Array.from(mySet);

Simply spreading the Set out in an array

let array = [...mySet];

The old fashion way, iterating and pushing to a new array (Sets do have forEach)

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

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

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

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