Object.setPrototypeOf(O, proto) IS in ES6

This one is a short one, just to confirm that finally Object.setPrototypeOf(obj, proto) made it into ES6.
The section 15.2.3.2 speaks clearly:

15.2.3.2 Object.setPrototypeOf ( O, proto )
When the setPrototypeOf function is called with arguments O and proto, the following steps are taken:

1. If Type(O) is not Object, then throw a TypeError exception.
2. If Type(proto) is neither Object or Null, then throw a TypeError exception.
3. Let status be the result of calling the [[SetInheritance]] internal method of O with argument proto.
4. ReturnIfAbrupt(status).
5. If status is false, then throw a TypeError exception.
6. Return O.

Without going into details, the most basic polyfill woud be like this:

(function(O,s){
O[s]||(O[s]=function(o,p){o.__proto__=p;return o})
}(Object,'setPrototypeOf'));

If you want to go into details, the full reliable polyfill is hard to write down due all inconsistencies across JS engines out there where the __proto__ setter cannot be reused which means it's not possible to trust this magic over objects created from null.
All you need to do is forget __proto__ and use the suggested polyfill until the day __proto__ can simply disappear from those specs pages.
Enjoy!

---

This is a full polyfill with some extra info you might want to analyze, whenever ployfill is strictly true or false.

	/*jslint devel: true, indent: 2 */
	// 15.2.3.2
	if (!Object.setPrototypeOf) {
	Object.setPrototypeOf = (function(Object, magic) {
	'use strict';
	var set;
	function checkArgs(O, proto) {
	if (typeof O !== 'object' || O === null) {
	throw new TypeError('can not set prototype on a non-object');
	}
	if (typeof proto !== 'object' && proto !== null) {
	throw new TypeError('can only set prototype to an object or null');
	}
	}
	function setPrototypeOf(O, proto) {
	checkArgs(O, proto);
	set.call(O, proto);
	return O;
	}
	try {
	// this works already in Firefox and Safari
	set = Object.getOwnPropertyDescriptor(Object.prototype, magic).set;
	set.call({}, null);
	} catch (o_O) {
	if (
	// IE < 11 cannot be shimmed
	Object.prototype !== {}[magic] ||
	// neither can any browser that actually
	// implemented __proto__ correctly
	// (all but old V8 will return here)
	{__proto__:null}.__proto__ === void 0
	// this case means null objects cannot be passed
	// through setPrototypeOf in a reliable way
	// which means here a **Sham** is needed instead
	) {
	return;
	}
	// nodejs 0.8 and 0.10 are (buggy and..) fine here
	// probably Chrome or some old Mobile stock browser
	set = function(proto) {
	this[magic] = proto;
	};
	// please note that this will **not** work
	// in those browsers that do not inherit
	// __proto__ by mistake from Object.prototype
	// in these cases we should probably throw an error
	// or at least be informed about the issue
	setPrototypeOf.polyfill = setPrototypeOf(
	setPrototypeOf({}, null),
	Object.prototype
	) instanceof Object;
	// setPrototypeOf.polyfill === true means it works as meant
	// setPrototypeOf.polyfill === false means it's not 100% reliable
	// setPrototypeOf.polyfill === undefined
	// or
	// setPrototypeOf.polyfill == null means it's not a polyfill
	// which means it works as expected
	// we can even delete Object.prototype.__proto__;
	}
	return setPrototypeOf;
	}(Object, '__proto__'));
	}

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