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var anObject = require('../internals/an-object'); var defineProperties = require('../internals/object-define-properties'); var enumBugKeys = require('../internals/enum-bug-keys'); var hiddenKeys = require('../internals/hidden-keys'); var html = require('../internals/html'); var documentCreateElement = require('../internals/document-create-element'); var sharedKey = require('../internals/shared-key');
var GT = '>'; var LT = '<'; var PROTOTYPE = 'prototype'; var SCRIPT = 'script'; var IE_PROTO = sharedKey('IE_PROTO');
var EmptyConstructor = function () { /* empty */ };
var scriptTag = function (content) { return LT + SCRIPT + GT + content + LT + '/' + SCRIPT + GT; };
// Create object with fake `null` prototype: use ActiveX Object with cleared prototype
var NullProtoObjectViaActiveX = function (activeXDocument) { activeXDocument.write(scriptTag('')); activeXDocument.close(); var temp = activeXDocument.parentWindow.Object; activeXDocument = null; // avoid memory leak
return temp; };
// Create object with fake `null` prototype: use iframe Object with cleared prototype
var NullProtoObjectViaIFrame = function () { // Thrash, waste and sodomy: IE GC bug
var iframe = documentCreateElement('iframe'); var JS = 'java' + SCRIPT + ':'; var iframeDocument; iframe.style.display = 'none'; html.appendChild(iframe); // https://github.com/zloirock/core-js/issues/475
iframe.src = String(JS); iframeDocument = iframe.contentWindow.document; iframeDocument.open(); iframeDocument.write(scriptTag('document.F=Object')); iframeDocument.close(); return iframeDocument.F; };
// Check for document.domain and active x support
// No need to use active x approach when document.domain is not set
// see https://github.com/es-shims/es5-shim/issues/150
// variation of https://github.com/kitcambridge/es5-shim/commit/4f738ac066346
// avoid IE GC bug
var activeXDocument; var NullProtoObject = function () { try { /* global ActiveXObject -- old IE */ activeXDocument = document.domain && new ActiveXObject('htmlfile'); } catch (error) { /* ignore */ } NullProtoObject = activeXDocument ? NullProtoObjectViaActiveX(activeXDocument) : NullProtoObjectViaIFrame(); var length = enumBugKeys.length; while (length--) delete NullProtoObject[PROTOTYPE][enumBugKeys[length]]; return NullProtoObject(); };
hiddenKeys[IE_PROTO] = true;
// `Object.create` method
// https://tc39.es/ecma262/#sec-object.create
module.exports = Object.create || function create(O, Properties) { var result; if (O !== null) { EmptyConstructor[PROTOTYPE] = anObject(O); result = new EmptyConstructor(); EmptyConstructor[PROTOTYPE] = null; // add "__proto__" for Object.getPrototypeOf polyfill
result[IE_PROTO] = O; } else result = NullProtoObject(); return Properties === undefined ? result : defineProperties(result, Properties); };
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