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

var has = require('../internals/has');
var toObject = require('../internals/to-object');
var sharedKey = require('../internals/shared-key');
var CORRECT_PROTOTYPE_GETTER = require('../internals/correct-prototype-getter');

var IE_PROTO = sharedKey('IE_PROTO');
var ObjectPrototype = Object.prototype;

// `Object.getPrototypeOf` method
// https://tc39.github.io/ecma262/#sec-object.getprototypeof
module.exports = CORRECT_PROTOTYPE_GETTER ? Object.getPrototypeOf : function (O) {
  O = toObject(O);
  if (has(O, IE_PROTO)) return O[IE_PROTO];
  if (typeof O.constructor == 'function' && O instanceof O.constructor) {
    return O.constructor.prototype;
  } return O instanceof Object ? ObjectPrototype : null;
};