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