core-js/internals/object-set-prototype-of.js

var anObject = require('../internals/an-object');
var aPossiblePrototype = require('../internals/a-possible-prototype');

// `Object.setPrototypeOf` method
// https://tc39.github.io/ecma262/#sec-object.setprototypeof
// Works with __proto__ only. Old v8 can't work with null proto objects.
/* eslint-disable no-proto */
module.exports = Object.setPrototypeOf || ('__proto__' in {} ? function () {
  var CORRECT_SETTER = false;
  var test = {};
  var setter;
  try {
    setter = Object.getOwnPropertyDescriptor(Object.prototype, '__proto__').set;
    setter.call(test, []);
    CORRECT_SETTER = test instanceof Array;
  } catch (error) { /* empty */ }
  return function setPrototypeOf(O, proto) {
    anObject(O);
    aPossiblePrototype(proto);
    if (CORRECT_SETTER) setter.call(O, proto);
    else O.__proto__ = proto;
    return O;
  };
}() : undefined);