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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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