How to get the first element of Set in ES6 ( EcmaScript 2015)

They don’t seem to expose the List to be accessible from the instanced Object. This is from the EcmaScript Draft:

23.2.4 Properties of Set Instances

Set instances are ordinary objects that inherit properties from the Set prototype. Set instances also have a [[SetData]] internal slot.

[[SetData]] is the list of values the Set is holding.

A possible solution (and a somewhat expensive one) is to grab an iterator and then call next() for the first value:

var x = new Set();
x.add({ a: 2 });
//get iterator:
var it = x.values();
//get first entry:
var first =;
//get value out of the iterator entry:
var value = first.value;
console.log(value); //1

Worth mentioning too:

Set.prototype.values === Set.prototype.keys

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