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

Standard library

// Works with __proto__ only. Old v8 can't work with null proto objects.
/* eslint-disable no-proto */
var validateSetPrototypeOfArguments = require('../internals/validate-set-prototype-of-arguments');

module.exports = Object.setPrototypeOf || ('__proto__' in {} ? function () { // eslint-disable-line
  var correctSetter = false;
  var test = {};
  var setter;
  try {
    setter = Object.getOwnPropertyDescriptor(Object.prototype, '__proto__').set;
    setter.call(test, []);
    correctSetter = test instanceof Array;
  } catch (e) { /* empty */ }
  return function setPrototypeOf(O, proto) {
    validateSetPrototypeOfArguments(O, proto);
    if (correctSetter) setter.call(O, proto);
    else O.__proto__ = proto;
    return O;
  };
}() : undefined);