object-get-own-property-names-external.js

// fallback for IE11 buggy Object.getOwnPropertyNames with iframe and window
var toIndexedObject = require('../internals/to-indexed-object');
var nativeGetOwnPropertyNames = require('../internals/object-get-own-property-names').f;
var toString = {}.toString;

var windowNames = typeof window == 'object' && window && Object.getOwnPropertyNames
  ? Object.getOwnPropertyNames(window) : [];

var getWindowNames = function (it) {
  try {
    return nativeGetOwnPropertyNames(it);
  } catch (error) {
    return windowNames.slice();
  }
};

module.exports.f = function getOwnPropertyNames(it) {
  return windowNames && toString.call(it) == '[object Window]'
    ? getWindowNames(it)
    : nativeGetOwnPropertyNames(toIndexedObject(it));
};