{"id":1455,"date":"2022-08-27T20:37:07","date_gmt":"2022-08-27T12:37:07","guid":{"rendered":"https:\/\/blog.cauchyschwarz.com\/?p=1455"},"modified":"2023-05-03T19:42:27","modified_gmt":"2023-05-03T11:42:27","slug":"professional-javascript-for-web-developers-3rd-edition-part-4","status":"publish","type":"post","link":"https:\/\/blog.cauchyschwarz.com\/?p=1455","title":{"rendered":"Professional JavaScript for Web Developers, 3rd Edition, Part 4"},"content":{"rendered":"\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_82_2 ez-toc-wrap-right counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-69e0a61656dd6\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-69e0a61656dd6\" checked aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#%E7%AC%AC6%E7%AB%A0_%E9%9D%A2%E5%90%91%E5%AF%B9%E8%B1%A1%E7%9A%84%E7%A8%8B%E5%BA%8F%E8%AE%BE%E8%AE%A1\" >\u7b2c6\u7ae0 \u9762\u5411\u5bf9\u8c61\u7684\u7a0b\u5e8f\u8bbe\u8ba1<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#1%E7%90%86%E8%A7%A3%E5%AF%B9%E8%B1%A1\" >1.\u7406\u89e3\u5bf9\u8c61<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#2%E5%88%9B%E5%BB%BA%E5%AF%B9%E8%B1%A1\" >2.\u521b\u5efa\u5bf9\u8c61<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#1%E5%B7%A5%E5%8E%82%E6%A8%A1%E5%BC%8F\" >1.\u5de5\u5382\u6a21\u5f0f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#2%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0%E6%A8%A1%E5%BC%8F\" >2.\u6784\u9020\u51fd\u6570\u6a21\u5f0f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#3%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F\" >3.\u539f\u578b\u6a21\u5f0f<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#a%E7%90%86%E8%A7%A3%E5%8E%9F%E5%9E%8B%E5%AF%B9%E8%B1%A1\" >a.\u7406\u89e3\u539f\u578b\u5bf9\u8c61<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#bin%E6%93%8D%E4%BD%9C%E7%AC%A6\" >b.in\u64cd\u4f5c\u7b26<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#3%E6%9B%B4%E7%AE%80%E5%8D%95%E7%9A%84%E5%8E%9F%E5%9E%8B%E8%AF%AD%E6%B3%95\" >3.\u66f4\u7b80\u5355\u7684\u539f\u578b\u8bed\u6cd5<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#4%E5%8E%9F%E5%9E%8B%E7%9A%84%E5%8A%A8%E6%80%81%E6%80%A7\" >4.\u539f\u578b\u7684\u52a8\u6001\u6027<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#5%E5%8E%9F%E7%94%9F%E5%AF%B9%E8%B1%A1%E7%9A%84%E5%8E%9F%E5%9E%8B\" >5.\u539f\u751f\u5bf9\u8c61\u7684\u539f\u578b<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#6%E5%8E%9F%E5%9E%8B%E5%AF%B9%E8%B1%A1%E7%9A%84%E9%97%AE%E9%A2%98\" >6.\u539f\u578b\u5bf9\u8c61\u7684\u95ee\u9898<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#4%E7%BB%84%E5%90%88%E4%BD%BF%E7%94%A8%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0%E6%A8%A1%E5%BC%8F%E5%92%8C%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F\" >4.\u7ec4\u5408\u4f7f\u7528\u6784\u9020\u51fd\u6570\u6a21\u5f0f\u548c\u539f\u578b\u6a21\u5f0f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#5%E5%8A%A8%E6%80%81%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F\" >5.\u52a8\u6001\u539f\u578b\u6a21\u5f0f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#6%E5%AF%84%E7%94%9F%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0%E6%A8%A1%E5%BC%8F\" >6.\u5bc4\u751f\u6784\u9020\u51fd\u6570\u6a21\u5f0f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#7%E7%A8%B3%E5%A6%A5%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0%E6%A8%A1%E5%BC%8F\" >7.\u7a33\u59a5\u6784\u9020\u51fd\u6570\u6a21\u5f0f<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#3%E7%BB%A7%E6%89%BF\" >3.\u7ee7\u627f<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#1%E5%8E%9F%E5%9E%8B%E9%93%BE\" >1.\u539f\u578b\u94fe<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#2%E5%80%9F%E7%94%A8%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0constructor_stealing\" >2.\u501f\u7528\u6784\u9020\u51fd\u6570(constructor stealing)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#3%E7%BB%84%E5%90%88%E7%BB%A7%E6%89%BFcombination_inheritance\" >3.\u7ec4\u5408\u7ee7\u627f(combination inheritance)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#4%E5%8E%9F%E5%9E%8B%E5%BC%8F%E7%BB%A7%E6%89%BFPrototypal_Inheritance\" >4.\u539f\u578b\u5f0f\u7ee7\u627f(Prototypal Inheritance)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-22\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#5%E5%AF%84%E7%94%9F%E5%BC%8F%E7%BB%A7%E6%89%BFparasitic_inheritance\" >5.\u5bc4\u751f\u5f0f\u7ee7\u627f(parasitic inheritance)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-23\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1455\/#6%E5%AF%84%E7%94%9F%E7%BB%84%E5%90%88%E5%BC%8F%E7%BB%A7%E6%89%BF\" >6.\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f<\/a><\/li><\/ul><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E7%AC%AC6%E7%AB%A0_%E9%9D%A2%E5%90%91%E5%AF%B9%E8%B1%A1%E7%9A%84%E7%A8%8B%E5%BA%8F%E8%AE%BE%E8%AE%A1\"><\/span>\u7b2c6\u7ae0 \u9762\u5411\u5bf9\u8c61\u7684\u7a0b\u5e8f\u8bbe\u8ba1<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p>ECMA-262\u628a\u5bf9\u8c61\u5b9a\u4e49\u4e3a\uff1a\u201c\u65e0\u5e8f\u5c5e\u6027\u7684\u96c6\u5408\uff0c\u5176\u5c5e\u6027\u53ef\u4ee5\u5305\u542b\u57fa\u672c\u503c\u3001\u5bf9\u8c61\u6216\u51fd\u6570\u201d\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1%E7%90%86%E8%A7%A3%E5%AF%B9%E8%B1%A1\"><\/span>1.\u7406\u89e3\u5bf9\u8c61<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u521b\u5efa\u5bf9\u8c61\u65f6\u53ef\u4ee5\u901a\u8fc7new Object()\u6765\u521b\u5efa\uff0c\u4e5f\u53ef\u4ee5\u901a\u8fc7\u5b57\u9762\u91cf\u7684\u65b9\u5f0f\u6765\u521b\u5efa\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">var person = {\n  name: \"Nicolas\",\n  age: 29,\n  job: \"Software Engineer\",\n\n  sayName: function() {\n    alert(this.name);\n  }\n};<\/code><\/pre>\n\n\n\n<p>1.1 \u5c5e\u6027\u7c7b\u578b<\/p>\n\n\n\n<p>\u5c5e\u6027\u7684\u5c5e\u6027\u7c7b\u4f3cC++\u91cc\u7684\u6ce8\u89e3\uff0c\u653e\u5728\u53cc\u91cd\u65b9\u62ec\u53f7\u91cc\uff0c\u63cf\u8ff0\u4e86\u5c5e\u6027\u7684\u884c\u4e3a\u7279\u5f81\u3002<\/p>\n\n\n\n<p><strong>\u6570\u636e\u5c5e\u6027<\/strong><\/p>\n\n\n\n<p>\u6570\u636e\u5c5e\u6027\u5305\u542b\u6570\u636e\u503c\u7684\u4f4d\u7f6e\uff0c\u5728\u8fd9\u4e2a\u4f4d\u7f6e\u53ef\u4ee5\u8bfb\u53d6\u548c\u5199\u5165\u503c\u3002\u6570\u636e\u5c5e\u6027\u5177\u6709\u4e0b\u5217\u7279\u6027\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>[[Configurable]] \u8868\u793a\u80fd\u5426\u901a\u8fc7delete\u5220\u9664\u5c5e\u6027\u4ece\u800c\u4ece\u65b0\u5b9a\u4e49\u5c5e\u6027\uff0c\u80fd\u5426\u4fee\u6539\u5c5e\u6027\u7684\u7279\u6027\uff0c\u6216\u8005\u80fd\u5426\u628a\u5c5e\u6027\u4fee\u6539\u4e3a\u8bbf\u95ee\u5668\u5c5e\u6027\u3002\u9ed8\u8ba4\u4e3atrue\u3002<\/li>\n\n\n\n<li>[[Enumerable]]\u8868\u793a\u80fd\u5426\u901a\u8fc7for-in\u5faa\u73af\u8fd4\u56de\u5c5e\u6027\uff0c\u9ed8\u8ba4\u4e3atrue\u3002<\/li>\n\n\n\n<li>[[Writable]]\u8868\u793a\u80fd\u5426\u4fee\u6539\u5c5e\u6027\u7684\u503c\u3002\u9ed8\u8ba4\u4e3atrue\u3002<\/li>\n\n\n\n<li>[[Value]]\u5305\u542b\u5c5e\u6027\u7684\u503c\u3002\u9ed8\u8ba4\u4e3aundefined\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u8981\u4fee\u6539\u5c5e\u6027\u9ed8\u8ba4\u7684\u7279\u6027\uff0c\u9700\u8981\u4f7f\u7528Object.defineProperty()\u65b9\u6cd5\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">var person = {};\nObject.defineProperty(person,\"name\", {writable: false, value: \"Nicholas\"});<\/code><\/pre>\n\n\n\n<p>\u628aconfigurable\u8bbe\u7f6e\u4e3afalse\u540e\uff0c\u4e0d\u80fd\u518d\u5c06\u5176\u8bbe\u7f6e\u4e3atrue\u3002<\/p>\n\n\n\n<p>\u5728\u4f7f\u7528Object.defineProperty()\u65b9\u6cd5\u521b\u5efa\u65b0\u7684\u5c5e\u6027\u65f6\uff0cconfigurable\uff0cenumerable\uff0cwritable\u7684\u9ed8\u8ba4\u503c\u662ffalse\u3002<\/p>\n\n\n\n<p><strong>\u8bbf\u95ee\u5668\u5c5e\u6027<\/strong><\/p>\n\n\n\n<p>\u8bbf\u95ee\u5668\u5c5e\u6027\u5305\u542b\u4e00\u5bf9get\/set\u51fd\u6570\uff0c\u76f8\u5f53\u4e8e\u91cd\u8f7d\u4e86\u5bf9\u8c61\u4e2d\u67d0\u4e2a\u5c5e\u6027\u7684\u8bfb\u5199\u51fd\u6570\uff0c\u4f46\u662f\u8fd9\u4e2a\u4e5f\u4e0d\u662f\u5b8c\u5168\u662f\u91cd\u8f7d\uff0c\u56e0\u4e3a\u770b\u4e0b\u9762\u7684\u793a\u4f8b\u4ee3\u7801\uff0c\u4e00\u4e2a\u662f_year\uff0c\u4e00\u4e2a\u662fyear\uff0c\u4e24\u4e2a\u540d\u5b57\u4e0d\u4e00\u6837\uff0c\u76f8\u5f53\u4e8e\u5b9a\u4e49\u4e86\u4e00\u4e2a\u4e0d\u7528\u52a0\u62ec\u53f7\u8c03\u7528\u7684\u51fd\u6570\u5427\u3002<\/p>\n\n\n\n<p>\u8bbf\u95ee\u5668\u5c5e\u6027\u5fc5\u987b\u4f7f\u7528Object.defineProperty\u6765\u5b9a\u4e49\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">var book = {\n  _year: 2004,\n  edition: 1\n};\n\nObject.defineProperty(book, \"year\", {\n  get: function() {\n    return this._year;\n  },\n  set: function(newValue) {\n    if (newValue &gt; 2004) {\n      thie._year = newValue;\n      this.edition += newValue - 2004;\n    }\n  }\n});\n\nbook.year = 2005;\nalert(book.edition);  \/\/ 2<\/code><\/pre>\n\n\n\n<p>\u53ef\u4ee5\u4e0d\u540c\u65f6\u6307\u5b9aget\/set\u51fd\u6570\uff0c\u4f46\u662f\u53ea\u6307\u5b9a\u5176\u4e2d\u4e00\u4e2aget\/set\u7684\u8bdd\uff0c\u610f\u5473\u7740\u5c31\u4e0d\u80fd\u5b9e\u73b0\u5bf9\u8be5\u5bf9\u8c61\u7684\u5199\/\u8bfb\u64cd\u4f5c\u3002<\/p>\n\n\n\n<p>\u8001\u65e7\u7248\u672c\u6d4f\u89c8\u5668\u53ef\u4ee5\u4f7f\u7528__defineGetter__()\u548c__defineSetter__()\u65b9\u6cd5\u5b9a\u4e49\u5bf9\u8c61\u5c5e\u6027\u7684set\/get\u65b9\u6cd5\u3002<\/p>\n\n\n\n<p>1.2\u5b9a\u4e49\u591a\u4e2a\u5c5e\u6027<\/p>\n\n\n\n<p>\u901a\u8fc7Object.defineProperties()\u65b9\u6cd5\u53ef\u4ee5\u4e00\u6b21\u6027\u5b9a\u4e49\u591a\u4e2a\u5c5e\u6027\u7684\u5c5e\u6027\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">var book = {};\n\nObject.defineProperties(book, {\n  _year: {\n    writable: true,\n    value: 2004\n  },\n\n  edition: {\n    writable: true,\n    value: 1\n  },\n\n  year: {\n    get: function() {\n      return this._year;\n    },\n    set: function(newValue) {\n      if (newValue &gt; 2004) {\n        this._year = newValue;\n        this.edition += newValue - 2004;\n      }\n    }\n  }\n});<\/code><\/pre>\n\n\n\n<p>1.3\u8bfb\u53d6\u5c5e\u6027\u7684\u7279\u6027<\/p>\n\n\n\n<p>\u901a\u8fc7Object.getOwnPropertyDescriptor()\u65b9\u6cd5\u53ef\u4ee5\u83b7\u53d6\u5c5e\u6027\u7684\u5c5e\u6027\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">var descriptor = Object.getOwnPropertyDescriptor(book, \"_year\");\nalert(descriptor.value);  \/\/ 2004\nalert(descriptor.configurable);  \/\/ false<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2%E5%88%9B%E5%BB%BA%E5%AF%B9%E8%B1%A1\"><\/span>2.\u521b\u5efa\u5bf9\u8c61<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1%E5%B7%A5%E5%8E%82%E6%A8%A1%E5%BC%8F\"><\/span>1.\u5de5\u5382\u6a21\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0%E6%A8%A1%E5%BC%8F\"><\/span>2.\u6784\u9020\u51fd\u6570\u6a21\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">function Person(name, age, job) {\n  this.name = name;\n  this.age = age;\n  this.job = job;\n  this.sayName = function() {\n    alert(this.name);\n  };\n}\n\nvar person1 = new Person(\"Nicholas\", 29, \"Software Engineer\");\nvar person2 = new Person(\"Greg\", 27, \"Doctor\");<\/code><\/pre>\n\n\n\n<p>\u6784\u9020\u51fd\u6570\u5fc5\u987b\u642d\u914dnew\u64cd\u4f5c\u7b26\u4f7f\u7528\uff0c\u4e14\u53ef\u4ee5\u770b\u5230\u6784\u9020\u51fd\u6570\u4f7f\u7528\u4e86this\u6307\u9488\uff0c\u4e14\u6ca1\u6709return\u8bed\u53e5\u3002<\/p>\n\n\n\n<p>\u8fd9\u6837\u4e00\u4e2a\u6784\u9020\u51fd\u6570\u5c31\u76f8\u5f53\u4e8e\u5b9a\u4e49\u4e86\u4e00\u4e2a\u7c7b\u3002<\/p>\n\n\n\n<p>\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\u521b\u5efa\u7684\u5bf9\u8c61\u7684constructor\u503c\u4e3a\u4f7f\u7528new\u64cd\u4f5c\u7b26\u65f6\u8c03\u7528\u7684\u6784\u9020\u51fd\u6570\uff0c\u5e76\u4e14\u53ef\u4ee5\u901a\u8fc7instanceof\u64cd\u4f5c\u7b26\u68c0\u9a8c\u5bf9\u8c61\u662f\u5426\u662f\u8fd9\u4e2a\u7c7b\u7684\u5b9e\u4f8b\u3002<\/p>\n\n\n\n<p>\u6784\u9020\u51fd\u6570\u53ef\u4ee5\u76f4\u63a5\u5f53\u505a\u666e\u901a\u51fd\u6570\u8c03\u7528\uff0c\u4f46\u6b64\u65f6\u7684\u6548\u679c\u5c31\u662f\u4e3aGlobal\u5bf9\u8c61\u6dfb\u52a0\/\u8bbe\u7f6e\u4e86\u5c5e\u6027\u3002<\/p>\n\n\n\n<p><a href=\"https:\/\/www.wlstudy.cn\/article\/62\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-red-color\">\u4f7f\u7528new\u64cd\u4f5c\u7b26\u548c\u4e0d\u4f7f\u7528new\u7684\u533a\u522b<\/mark><\/a>\uff1a<mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-red-color\">\u4f7f\u7528\u4e86new\u64cd\u4f5c\u7b26\uff0c\u65b0\u521b\u5efa\u5bf9\u8c61\u7684this\u6307\u9488\u6307\u5411\u65b0\u521b\u5efa\u5bf9\u8c61\u81ea\u5df1\uff0c\u5426\u5219\u65b0\u521b\u5efa\u5bf9\u8c61\u7684this\u6307\u9488\u6307\u5411Global\u5bf9\u8c61\u3002<\/mark><\/p>\n\n\n\n<p>\u4e0a\u9762\u7684\u5b9e\u4f8b\u4ee3\u7801\u4e2d\u4e3a\u5bf9\u8c61\u6dfb\u52a0\u7684sayName\u51fd\u6570\u5b9e\u9645\u4e0a\u5bf9\u4e8e\u6bcf\u4e2a\u521b\u5efa\u7684\u5bf9\u8c61\u90fd\u662f\u6709\u4e00\u4e2a\u72ec\u7acb\u7684\u5b9e\u4f8b\u7684\u3002\u5982\u679c\u8981\u8ba9\u540c\u4e00\u4e2a\u7c7b\u7684\u6240\u6709\u5bf9\u8c61\u90fd\u5171\u4eab\u540c\u4e00\u4e2a\u7c7b\u65b9\u6cd5\u7684\u5b9e\u4f8b\uff0c\u9700\u8981\u5728\u6784\u9020\u51fd\u6570\u5916\u90e8\u5b9a\u4e49\u8fd9\u4e2a\u7c7b\u65b9\u6cd5\uff0c\u7136\u540e\u8ba9\u6784\u9020\u51fd\u6570\u91cc\u7684\u65b9\u6cd5\u540d\u6307\u5411\u8fd9\u4e2a\u51fd\u6570\u3002\u4f46\u662f\u8fd9\u6837\u505a\u5462\u53c8\u4f1a\u5bfc\u81f4\u8981\u5728\u6784\u9020\u51fd\u6570\u5916\u9762\u5b9a\u4e49\u5f88\u591a\u7684\u5168\u5c40\u51fd\u6570\uff0c\u6240\u4ee5\u8fd9\u4e2a\u65f6\u5019\u539f\u578b\u6a21\u5f0f\u51fa\u573a\u4e86\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F\"><\/span>3.\u539f\u578b\u6a21\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u6bcf\u4e2a\u51fd\u6570\u90fd\u5305\u542b\u6709\u4e00\u4e2a\u540d\u4e3aprototype\u7684(\u539f\u578b)\u5c5e\u6027\uff0c\u8fd9\u4e2a\u5c5e\u6027\u6307\u5411\u4e00\u4e2a\u53ef\u4ee5\u5305\u542b\u5171\u4eab\u5c5e\u6027\u548c\u65b9\u6cd5\u7684\u5bf9\u8c61\u3002prototype\u539f\u578b\u5bf9\u8c61\u7684constructor\u5c5e\u6027\u9ed8\u8ba4\u4e3a\u5305\u542b\u8fd9\u4e2aprototype\u539f\u578b\u5bf9\u8c61\u7684\u51fd\u6570\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"a%E7%90%86%E8%A7%A3%E5%8E%9F%E5%9E%8B%E5%AF%B9%E8%B1%A1\"><\/span>a.\u7406\u89e3\u539f\u578b\u5bf9\u8c61<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n\n<p>\u901a\u8fc7\u6784\u9020\u51fd\u6570\u521b\u5efa\u4e00\u4e2a\u5b9e\u4f8b\u540e\uff0c\u8be5\u5b9e\u4f8b\u5185\u90e8\u5c06\u5305\u542b\u4e00\u4e2a\u6307\u5411\u539f\u578b\u5bf9\u8c61\u7684\u6307\u9488__proto__(\u5373[[Prototype]])\u3002\u5f53\u6211\u4eec\u7528a.attribute\u7684\u8bed\u6cd5\u8bbf\u95ee\u5bf9\u8c61a\u7684\u5c5e\u6027\/\u65b9\u6cd5attribute\u65f6\uff0c\u89e3\u91ca\u5668\u4f1a\u5148\u67e5\u627e\u5bf9\u8c61a\u81ea\u5df1\u662f\u5426\u5177\u6709\u8fd9\u4e2a\u5c5e\u6027\/\u65b9\u6cd5\uff0c\u5982\u679c\u6ca1\u6709\u518d\u67e5\u627e\u539f\u578b\u5bf9\u8c61\u662f\u5426\u5177\u6709\u8fd9\u4e2a\u5c5e\u6027\/\u65b9\u6cd5\u3002<\/p>\n\n\n\n<p>\u5f53\u4e3a\u5b9e\u4f8b\u6dfb\u52a0\u548c\u539f\u578b\u5bf9\u8c61\u4e2d\u7684\u540c\u540d\u5c5e\u6027\/\u65b9\u6cd5\u65f6\uff0c\u5b9e\u4f8b\u81ea\u5df1\u7684\u5c5e\u6027\/\u65b9\u6cd5\u4f1a\u5c4f\u853d\u539f\u578b\u5bf9\u8c61\u4e2d\u7684\u540c\u540d\u5c5e\u6027\/\u65b9\u6cd5\uff0c\u53ea\u6709\u4f7f\u7528<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-red-color\">delete\u64cd\u4f5c\u7b26<\/mark><\/strong>\u5220\u9664\u5b9e\u4f8b\u5c5e\u6027\u624d\u53ef\u4ee5\u518d\u6b21\u8bbf\u95ee\u539f\u578b\u5bf9\u8c61\u4e2d\u7684\u5c5e\u6027\/\u65b9\u6cd5\u3002<\/p>\n\n\n\n<p>isPrototypeOf()\u65b9\u6cd5\u53ef\u4ee5\u7528\u6765\u5224\u5b9a\u4e00\u4e2a\u5bf9\u8c61\u662f\u5426\u4e3a\u53e6\u4e00\u4e2a\u5bf9\u8c61\u7684\u539f\u578b\u5bf9\u8c61\u3002<\/p>\n\n\n\n<p>ECMAScript 5\u589e\u52a0\u4e86Object.getPrototypeOf()\u65b9\u6cd5\u6765\u83b7\u53d6\u539f\u578b\u5bf9\u8c61\u3002<\/p>\n\n\n\n<p>hasOwnProperty\u65b9\u6cd5\u53ef\u4ee5\u68c0\u6d4b\u4e00\u4e2a\u5c5e\u6027\u662f\u5426\u5b58\u5728\u4e8e\u5b9e\u4f8b\u4e2d\u8fd8\u662f\u539f\u578b\u5bf9\u8c61\u4e2d\uff0c\u53ea\u6709\u5b58\u5728\u4e8e\u5bf9\u8c61\u5b9e\u4f8b\u4e2d\u65f6\uff0c\u624d\u4f1a\u8fd4\u56detrue\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"bin%E6%93%8D%E4%BD%9C%E7%AC%A6\"><\/span>b.in\u64cd\u4f5c\u7b26<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n\n<p>in\u64cd\u4f5c\u7b26\u53ef\u4ee5\u5355\u72ec\u4f7f\u7528\u548c\u653e\u5728for\u5faa\u73af\u91cc\uff0cfor-in\u5faa\u73af\u8fd4\u56de\u7684\u662f\u6240\u6709\u80fd\u591f\u901a\u8fc7\u5bf9\u8c61\u8bbf\u95ee\u7684\u3001\u53ef\u679a\u4e3e\u7684\u5c5e\u6027\uff0c\u65e2\u5305\u62ec\u5b9e\u4f8b\u4e2d\u7684\u5c5e\u6027\uff0c\u4e5f\u5305\u62ec\u539f\u578b\u5bf9\u8c61\u4e2d\u7684\u5c5e\u6027\u3002for-in\u5faa\u73af\u4e2d\uff0c\u5b9e\u4f8b\u5c5e\u6027\u4f1a\u5c4f\u853d\u539f\u578b\u5bf9\u8c61\u4e2d\u7684\u5c5e\u6027\u3002<\/p>\n\n\n\n<p>\u4e5f\u53ef\u4ee5\u4f7f<strong>\u7528Object.keys()<\/strong>\u548c<strong>Object.getOwnPropertyNames()<\/strong>\u65b9\u6cd5\u83b7\u53d6\u5c5e\u6027\u540d\u5b57\u7684\u96c6\u5408\uff0c\u533a\u522b\u5728\u4e8e\uff1a<\/p>\n\n\n\n<p>Object.keys()\u8fd4\u56de\u7684\u662f\u5bf9\u8c61\u81ea\u5df1\u7684\u5c5e\u6027\uff0c\u4e0d\u5305\u62ec\u539f\u578b\u5bf9\u8c61\u7684\u5c5e\u6027\uff0c\u4e5f\u4e0d\u5305\u62ec\u4e0d\u80fd\u679a\u4e3e\u7684\u5c5e\u6027\uff1b<\/p>\n\n\n\n<p>Object.getOwnPropertyNames()\u65b9\u6cd5\u8fd4\u56de\u7684\u662f\u5bf9\u8c61\u81ea\u5df1\u7684\u5c5e\u6027\uff0c\u4e0d\u5305\u62ec\u539f\u578b\u5bf9\u8c61\u7684\u5c5e\u6027\uff0c\u5305\u62ec\u4e0d\u80fd\u679a\u4e3e\u7684\u5c5e\u6027\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3%E6%9B%B4%E7%AE%80%E5%8D%95%E7%9A%84%E5%8E%9F%E5%9E%8B%E8%AF%AD%E6%B3%95\"><\/span>3.\u66f4\u7b80\u5355\u7684\u539f\u578b\u8bed\u6cd5<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n\n<p>\u539f\u578b\u5bf9\u8c61\u53ef\u4ee5\u901a\u8fc7\u5b57\u9762\u91cf\u7684\u65b9\u5f0f\u521b\u5efa\uff0c\u4f46\u662f\u8fd9\u65f6\u5019\u9700\u8981\u624b\u52a8\u8bbe\u7f6e\u5176constructor\u5c5e\u6027\uff0c\u5e76\u4e14\u6b64\u65f6constructor\u7684[[Enumerable]]\u7279\u6027\u88ab\u8bbe\u7f6e\u4e3atrue\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4%E5%8E%9F%E5%9E%8B%E7%9A%84%E5%8A%A8%E6%80%81%E6%80%A7\"><\/span>4.\u539f\u578b\u7684\u52a8\u6001\u6027<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n\n<p>\u5728\u539f\u578b\u4e2d\u67e5\u627e\u503c\u662f\u4e00\u4e2a\u52a8\u6001\u8fc7\u7a0b\uff0c\u56e0\u6b64\u5bf9\u539f\u578b\u5bf9\u8c61\u6240\u505a\u7684\u4efb\u4f55\u4fee\u6539\u90fd\u80fd\u591f\u7acb\u5373\u4ece\u5b9e\u4f8b\u4e0a\u53cd\u6620\u51fa\u6765\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">var friend = new Person();\n\nPerson.prototype.sayHi = function() {\n  alert(\"hi\");\n}\n\nfriend.sayHi();<\/code><\/pre>\n\n\n\n<p>friend\u5bf9\u8c61\u867d\u7136\u5728sayHi\u51fd\u6570\u4e4b\u524d\u521b\u5efa\uff0c\u4f46\u662f\u67e5\u627esayHi\u51fd\u6570\u65f6\u6309\u7167\u73b0\u5728friend\u5b9e\u4f8b\u4e2d\u67e5\u627e\uff0c\u518d\u5728Person\u539f\u578b\u5bf9\u8c61\u4e2d\u67e5\u627e\u7684\u987a\u5e8f\uff0c\u800c\u5728Person\u539f\u578b\u5bf9\u8c61\u4e2d\u67e5\u627e\u65f6\u76f8\u5f53\u4e8e\u6309\u6307\u9488\u67e5\u627e\u3002<\/p>\n\n\n\n<p>\u53ef\u4ee5\u968f\u65f6\u4fee\u6539\u539f\u578b\u5bf9\u8c61\u4e2d\u7684\u5c5e\u6027\u548c\u65b9\u6cd5\uff0c\u5e76\u4e14\u80fd\u591f\u7acb\u5373\u5728\u6240\u6709\u5bf9\u8c61\u5b9e\u4f8b\u4e2d\u53cd\u6620\u51fa\u6765\uff0c\u4f46\u5982\u679c\u662f\u91cd\u5199\u6574\u4e2a\u539f\u578b\u5bf9\u8c61\uff0c\u5c31\u76f8\u5f53\u4e8e\u6539\u53d8\u4e86\u539f\u578b\u5bf9\u8c61\u6307\u9488\u6307\u5411\u7684\u5bf9\u8c61\uff0c\u5728\u8fd9\u4e4b\u524d\u521b\u5efa\u7684\u5b9e\u4f8b\u4e2d\u7684\u539f\u578b\u5bf9\u8c61\u6307\u9488\u5c31\u5931\u6548\u4e86\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">function Person() {}\n\nvar friend = new Person();\n\nPerson.prototype = {\n  constructor: Person,\n  name: \"Nicholas\",\n  age: 29,\n  job: \"Software Engineer\",\n  sayName: function() {\n    alert(this.name);\n  }\n};\n\nfriend.sayName(); \/\/ error, friend\u5b9e\u4f8b\u4e2d\u7684\u539f\u578b\u5bf9\u8c61\u5df2\u7ecf\u5931\u6548\u4e86<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"5%E5%8E%9F%E7%94%9F%E5%AF%B9%E8%B1%A1%E7%9A%84%E5%8E%9F%E5%9E%8B\"><\/span>5.\u539f\u751f\u5bf9\u8c61\u7684\u539f\u578b<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n\n<p>\u53ef\u4ee5\u4fee\u6539\u539f\u751f\u5f15\u7528\u7c7b\u578b\u7684\u539f\u578b\u5bf9\u8c61\u4e2d\u7684\u65b9\u6cd5\u548c\u5c5e\u6027\uff0c\u4f46\u662f\u4e0d\u63a8\u8350\u8fd9\u4e48\u505a\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"6%E5%8E%9F%E5%9E%8B%E5%AF%B9%E8%B1%A1%E7%9A%84%E9%97%AE%E9%A2%98\"><\/span>6.\u539f\u578b\u5bf9\u8c61\u7684\u95ee\u9898<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n\n<p>\u539f\u578b\u5bf9\u8c61\u7684\u95ee\u9898\u5728\u4e8e\u539f\u578b\u5bf9\u8c61\u4e2d\u7684\u5c5e\u6027\u662f\u6240\u6709\u5b9e\u4f8b\u5171\u4eab\u7684\uff0c\u4e00\u4e2a\u5b9e\u4f8b\u4fee\u6539\u4e86\u539f\u578b\u5bf9\u8c61\u7684\u5c5e\u6027\uff0c\u53e6\u4e00\u4e2a\u5b9e\u4f8b\u4e5f\u4f1a\u7acb\u5373\u611f\u53d7\u5230\u8fd9\u4e2a\u5c5e\u6027\u7684\u6539\u53d8\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4%E7%BB%84%E5%90%88%E4%BD%BF%E7%94%A8%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0%E6%A8%A1%E5%BC%8F%E5%92%8C%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F\"><\/span>4.\u7ec4\u5408\u4f7f\u7528\u6784\u9020\u51fd\u6570\u6a21\u5f0f\u548c\u539f\u578b\u6a21\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5b9e\u4f8b\u7684\u79c1\u6709\u5c5e\u6027\u5378\u8f7d\u6784\u9020\u51fd\u6570\u91cc\uff0c\u516c\u7528\u7684\u65b9\u6cd5\u5199\u5728\u539f\u578b\u5bf9\u8c61\u91cc\uff0c\u4ee5\u6700\u5927\u9650\u5ea6\u5730\u8282\u7701\u7a7a\u95f4\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">function Person(name, age, job) {\n  this.name = name;\n  this.age = age;\n  this.job = job;\n  this.friends = [\"Shellby\", \"Court\"];\n}\n\nPerson.prototype = {\n  constructor: Person,\n  sayName: function() {\n    alert(this.name);\n  }\n}\n\nvar Person1 = new Person(\"Nicholas\", 29, \"Software Engineer\");\nvar Person2 = new Person(\"Greg\", 27, \"Doctor\");\n\nperson1.friends.push(\"Van\");\nalert(person1.friends);\nalert(person2.friends);\nalert(person1.friends === person2.friends); \/\/ false\nalert(person1.sayName === person2.sayName); \/\/ true<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"5%E5%8A%A8%E6%80%81%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F\"><\/span>5.\u52a8\u6001\u539f\u578b\u6a21\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u52a8\u6001\u539f\u578b\u6a21\u5f0f\uff1a\u628a\u6240\u6709\u7684\u903b\u8f91\u90fd\u5c01\u88c5\u5728\u6784\u9020\u51fd\u6570\u91cc\uff0c\u5e76\u4e14\u539f\u578b\u5bf9\u8c61\u4e5f\u662f\u5728\u6784\u9020\u51fd\u6570\u4e2d\u52a8\u6001\u521d\u59cb\u5316\u7684\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">function Person(name, age, job) {\n  this.name = name;\n  this.age = age;\n  this.job = job;\n\n  if (typeof this.sayName != \"function\") {\n    Person.prototype.sayName = function() {\n      alert(this.name);\n    }\n  }\n}\n\nvar friend = new Person(\"Nicholas\", 29, \"Software Engineer\");\nfriend.sayName();<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"6%E5%AF%84%E7%94%9F%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0%E6%A8%A1%E5%BC%8F\"><\/span>6.\u5bc4\u751f\u6784\u9020\u51fd\u6570\u6a21\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5bc4\u751f(parasitic)\u6784\u9020\u51fd\u6570\u6a21\u5f0f\uff1a\u5728\u6784\u9020\u51fd\u6570\u5185\u90e8\u521b\u5efa\u5e76\u8fd4\u56de\u5bf9\u8c61\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">function Person(name, age, job) {\n  var o = new Object();\n  o.name = name;\n  o.age = age;\n  o.job = job;\n  o.sayName = function() {\n    alert(this.name);\n  }\n  return o;\n}\n\nvar friend = new Person(\"Nicholas\", 29, \"Software Engineer\");\nfriend.sayName();<\/code><\/pre>\n\n\n\n<p>\u6784\u9020\u51fd\u6570\u9ed8\u8ba4\u8fd4\u56de\u65b0\u5bf9\u8c61\u5b9e\u4f8b\uff0c\u4f46\u662f\u8fd9\u91cc\u901a\u8fc7return\u8bed\u53e5\u8fd4\u56de\u4e86\u5185\u90e8\u521b\u5efa\u7684\u5bf9\u8c61\u3002\u8fd9\u4e2a\u5185\u90e8\u521b\u5efa\u7684\u5bf9\u8c61o\u4e0ePerson\u7c7b\u7684\u6784\u9020\u51fd\u6570\u548c\u539f\u578b\u5bf9\u8c61\u6ca1\u6709\u4efb\u4f55\u5173\u7cfb\uff0c\u4e0e\u5728\u6784\u9020\u51fd\u6570\u5916\u90e8\u521b\u5efa\u7684\u5bf9\u8c61\u6ca1\u6709\u533a\u522b\u3002<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-red-color\">\u4f7f\u7528\u5bc4\u751f\u6784\u9020\u51fd\u6570\u521b\u5efa\u7684\u5bf9\u8c61\u4e0d\u80fd\u7528instanceof\u64cd\u4f5c\u7b26\u6765\u786e\u5b9a\u5bf9\u8c61\u7c7b\u578b<\/mark>\uff0c\u6240\u4ee5\u4e00\u822c\u4e0d\u8981\u4f7f\u7528\u8fd9\u79cd\u6a21\u5f0f\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"7%E7%A8%B3%E5%A6%A5%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0%E6%A8%A1%E5%BC%8F\"><\/span>7.\u7a33\u59a5\u6784\u9020\u51fd\u6570\u6a21\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u7a33\u59a5\u5bf9\u8c61(durable objects)\uff1a\u6ca1\u6709\u516c\u5171\u5c5e\u6027\u4e5f\u6ca1\u6709this\u7684\u5bf9\u8c61\uff0c\u53ea\u80fd\u901a\u8fc7\u5176\u65b9\u6cd5\u8bbf\u95ee\u5176\u5185\u90e8\u5c5e\u6027\u3002<\/p>\n\n\n\n<p>\u7a33\u59a5\u6784\u9020\u51fd\u6570\u7684\u8981\u6c42\uff1a1.\u65b0\u521b\u5efa\u5bf9\u8c61\u7684\u5b9e\u4f8b\u65b9\u6cd5\u4e0d\u5f15\u7528this\uff0c2.\u4e0d\u4f7f\u7528new\u64cd\u4f5c\u7b26\u8c03\u7528\u6784\u9020\u51fd\u6570\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">function Person(name, age, job)  {\n  var o = new Object();\n  o.sayName = function() {\n    alert(name);\n  }\n  return o;\n}\n\nvar friend = Person(\"Nicholas\", 29, \"Software Engineer\");\nfriend.sayName();<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3%E7%BB%A7%E6%89%BF\"><\/span>3.\u7ee7\u627f<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1%E5%8E%9F%E5%9E%8B%E9%93%BE\"><\/span>1.\u539f\u578b\u94fe<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u901a\u8fc7\u539f\u578b\u94fe\u5b9e\u73b0\u7ee7\u627f\u7684\u65b9\u5f0f\uff1a\u8ba9\u5b50\u7c7b\u7684\u539f\u578b\u5bf9\u8c61\u6307\u5411\u7236\u7c7b\u7684\u4e00\u4e2a\u5b9e\u4f8b\u3002<\/p>\n\n\n\n<p>\u5bf9\u4e00\u4e2a\u5b50\u7c7b\u5bf9\u8c61\u641c\u7d22\u5c5e\u6027\u548c\u65b9\u6cd5\u65f6\uff0c\u9996\u5148\u5728\u8be5\u5b50\u7c7b\u5bf9\u8c61\u4e2d\u641c\u7d22\uff0c\u7136\u540e\u5728\u5b50\u7c7b\u7684\u539f\u578b\u5bf9\u8c61\u4e2d\u641c\u7d22\uff0c\u7531\u4e8e\u5b50\u7c7b\u7684\u539f\u578b\u5bf9\u8c61\u6307\u5411\u4e86\u4e00\u4e2a\u7236\u7c7b\u7684\u5bf9\u8c61\uff0c\u4f1a\u73b0\u5728\u7236\u7c7b\u7684\u5bf9\u8c61\u4e2d\u641c\u7d22\uff0c\u6700\u540e\u624d\u5728\u7236\u7c7b\u7684\u539f\u578b\u5bf9\u8c61\u4e2d\u641c\u7d22\u3002<\/p>\n\n\n\n<p>\u6240\u6709\u5f15\u7528\u7c7b\u578b\u90fd\u7ee7\u627f\u4e86Object\uff0c\u800c\u8fd9\u4e2a\u7ee7\u627f\u4e5f\u662f\u901a\u8fc7\u539f\u578b\u94fe\u5b9e\u73b0\u7684\u3002\u6240\u6709\u51fd\u6570\u7684\u9ed8\u8ba4\u539f\u578b\u90fd\u662fObject\u7684\u5b9e\u4f8b\uff0c\u56e0\u6b64\u9ed8\u8ba4\u539f\u578b\u90fd\u4f1a\u5305\u542b\u4e00\u4e2a\u5185\u90e8\u6307\u9488\u6307\u5411Object.prototype\u3002<\/p>\n\n\n\n<p>\u53ef\u4ee5\u901a\u8fc7instanceof\u64cd\u4f5c\u7b26\u6765\u786e\u5b9a\u539f\u578b\u548c\u5b9e\u4f8b\u4e4b\u95f4\u7684\u5173\u7cfb\u3002\u5176\u6b21\u53ef\u4ee5\u901a\u8fc7isPrototypeOf()\u65b9\u6cd5\u5224\u65ad\u539f\u578b\u548c\u5b9e\u4f8b\u4e4b\u95f4\u7684\u5173\u7cfb\u3002<\/p>\n\n\n\n<p>\u4e0d\u80fd\u4f7f\u7528\u5bf9\u8c61\u5b57\u9762\u91cf\u521b\u5efa\u539f\u578b\u65b9\u6cd5\uff0c\u8fd9\u6837\u4f1a\u91cd\u5199\u539f\u578b\u94fe\u3002<\/p>\n\n\n\n<p>\u539f\u578b\u94fe\u7684\u95ee\u9898\uff1a<\/p>\n\n\n\n<p>1.\u5b50\u7c7b\u539f\u578b\u5bf9\u8c61\u6307\u5411\u7236\u7c7b\u5b9e\u4f8b\u65f6\uff0c\u6240\u6709\u5b50\u7c7b\u5bf9\u8c61\u90fd\u4f1a\u5171\u4eab\u8fd9\u4e2a\u7236\u7c7b\u5b9e\u4f8b\u4e2d\u7684\u5c5e\u6027\uff1b<\/p>\n\n\n\n<p>2.\u5728\u521b\u5efa\u5b50\u7c7b\u5b9e\u4f8b\u65f6\uff0c\u4e0d\u80fd\u5411\u8d85\u7c7b\u578b\u7684\u6784\u9020\u51fd\u6570\u4e2d\u4f20\u9012\u53c2\u6570\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2%E5%80%9F%E7%94%A8%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0constructor_stealing\"><\/span>2.\u501f\u7528\u6784\u9020\u51fd\u6570(constructor stealing)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u501f\u7528\u6784\u9020\u51fd\u6570\u4e5f\u53eb\u4f2a\u9020\u5bf9\u8c61\u6216\u8005\u7ecf\u5178\u7ee7\u627f\u3002<\/p>\n\n\n\n<p>\u501f\u7528\u6784\u9020\u51fd\u6570\u5b9e\u9645\u4e0a\u662f\u5728\u5b50\u7c7b\u7684\u6784\u9020\u51fd\u6570\u4e2d\u901a\u8fc7call\/apply\u65b9\u6cd5\u76f4\u63a5\u6267\u884c\u4e86&#8221;\u7236\u7c7b&#8221;\u7684\u6784\u9020\u51fd\u6570\uff0c\u56e0\u6b64\u8fd9\u79cd\u7ee7\u627f\u5b9e\u9645\u4e0a\u662f\u4e00\u79cd\u4f2a\u7ee7\u627f\u3002<\/p>\n\n\n\n<p>\u501f\u7528\u6784\u9020\u51fd\u6570\u53ef\u4ee5\u5b9e\u73b0\u4e3a\u6bcf\u4e2a\u5b50\u7c7b\u5b9e\u4f8b\u63d0\u4f9b\u81ea\u5df1\u72ec\u6709\u7684&#8221;\u7ee7\u627f&#8221;\u5c5e\u6027\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">function SuperType() {\n    this.colors = [\"red\", \"blue\", \"green\"];\n}\n\nfunction SubType() {\n    \/\/ \u7ee7\u627f\u4e86SuperType\n    SuperType.call(this);\n}\n\nvar instance1 = new SubType();\ninstance1.colors.push(\"black\");\nalert(instance1.colors);    \/\/ \"red,blue,green,black\"\n\nvar instance2 = new SubType();\nalert(instance2.colors);    \/\/ \"red,blue,green\"<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3%E7%BB%84%E5%90%88%E7%BB%A7%E6%89%BFcombination_inheritance\"><\/span>3.\u7ec4\u5408\u7ee7\u627f(combination inheritance)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u53c8\u540d\u4f2a\u7ecf\u5178\u7ee7\u627f\uff0c\u662f\u4e00\u79cd\u5c06\u539f\u578b\u94fe\u548c\u501f\u7528\u6784\u9020\u51fd\u6570\u7ec4\u5408\u7684\u65b9\u6cd5\u3002<mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-red-color\">\u662fJavaScript\u4e2d\u6700\u5e38\u7528\u7684\u7ee7\u627f\u6a21\u5f0f\u3002<\/mark><\/p>\n\n\n\n<p>\u7f3a\u70b9\u5728\u4e8e\u4f1a\u5b58\u5728\u4e24\u7ec4\u540d\u5b57\u76f8\u540c\u7684\u5c5e\u6027\uff0c\u4e00\u7ec4\u5728\u5b50\u7c7b\u5bf9\u8c61\u4e2d\uff0c\u4e00\u7ec4\u5728\u5b50\u7c7b\u7684\u539f\u578b\u5bf9\u8c61\u6307\u5411\u7684\u7236\u7c7b\u5bf9\u8c61\u4e2d\u3002\u89e3\u51b3\u65b9\u6cd5\u89c1\u540e\u9762\u7684\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">        function SuperType(name){\n            this.name = name;\n            this.colors = [\"red\", \"blue\", \"green\"];\n        }\n        \n        SuperType.prototype.sayName = function(){\n            alert(this.name);\n        };\n\n        function SubType(name, age){  \n            SuperType.call(this, name);\n            \n            this.age = age;\n        }\n\n        SubType.prototype = new SuperType();\n        \n        SubType.prototype.sayAge = function(){\n            alert(this.age);\n        };\n        \n        var instance1 = new SubType(\"Nicholas\", 29);\n        instance1.colors.push(\"black\");\n        alert(instance1.colors);  \/\/\"red,blue,green,black\"\n        instance1.sayName();      \/\/\"Nicholas\";\n        instance1.sayAge();       \/\/29\n        \n       \n        var instance2 = new SubType(\"Greg\", 27);\n        alert(instance2.colors);  \/\/\"red,blue,green\"\n        instance2.sayName();      \/\/\"Greg\";\n        instance2.sayAge();       \/\/27\n<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4%E5%8E%9F%E5%9E%8B%E5%BC%8F%E7%BB%A7%E6%89%BFPrototypal_Inheritance\"><\/span>4.\u539f\u578b\u5f0f\u7ee7\u627f(Prototypal Inheritance)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u539f\u578b\u5f0f\u7ee7\u627f\u4e0e\u539f\u578b\u94fe\u7c7b\u4f3c\uff0c\u533a\u522b\u5728\u4e8e\u4e0d\u9700\u8981\u5174\u5e08\u52a8\u4f17\u5730\u521b\u5efa\u6784\u9020\u51fd\u6570\uff0c\u800c\u662f\u901a\u8fc7\u5bf9\u4e00\u4e2a\u5df2\u6709\u7684\u5bf9\u8c61\u505a\u4fee\u6539\u521b\u4f5c\u51fa\u65b0\u7684\u7c7b\u4f3c\u5bf9\u8c61\u3002\u6240\u4ee5\u539f\u578b\u5f0f\u7ee7\u627f\u521b\u9020\u7684\u65b0\u5bf9\u8c61\u4ecd\u7136\u662f\u5171\u4eab&#8221;\u7236\u7c7b&#8221;\u5bf9\u8c61\u7684\u5c5e\u6027\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">function object(o) {\n    function F() {}\n    F.prototype = o;\n    return new F();\n}<\/code><\/pre>\n\n\n\n<p>ECMAScript5\u901a\u8fc7\u65b0\u589eObject.create()\u65b9\u6cd5\u89c4\u8303\u5316\u4e86\u539f\u578b\u5f0f\u7ee7\u627f\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">        var person = {\n            name: \"Nicholas\",\n            friends: [\"Shelby\", \"Court\", \"Van\"]\n        };\n        \n        var anotherPerson = Object.create(person);\n        anotherPerson.name = \"Greg\";\n        anotherPerson.friends.push(\"Rob\");\n        \n        var yetAnotherPerson = Object.create(person);\n        yetAnotherPerson.name = \"Linda\";\n        yetAnotherPerson.friends.push(\"Barbie\");\n        \n        alert(person.friends);   \/\/\"Shelby,Court,Van,Rob,Barbie\"\n<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"5%E5%AF%84%E7%94%9F%E5%BC%8F%E7%BB%A7%E6%89%BFparasitic_inheritance\"><\/span>5.\u5bc4\u751f\u5f0f\u7ee7\u627f(parasitic inheritance)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5bc4\u751f\u5f0f\u7ee7\u627f\u7c7b\u4f3c\u4e8e\u5de5\u5382\u6a21\u5f0f\uff0c\u4f46\u53c8\u5e76\u4e0d\u662f\u5b8c\u5168\u7684\u5de5\u5382\u6a21\u5f0f\uff0c\u5bc4\u751f\u5f0f\u7ee7\u627f\u4f1a\u5bf9\u6784\u9020\u51fd\u6570\u751f\u6210\u7684\u5bf9\u8c61\u4f5c\u4fee\u6539\uff0c\u5e76\u4e14\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\u4e3a\u65b0\u5bf9\u8c61\u6dfb\u52a0\u7684\u51fd\u6570\u4e0d\u80fd\u505a\u5230\u51fd\u6570\u590d\u7528\uff0c\u4f1a\u964d\u4f4e\u7a0b\u5e8f\u7684\u6548\u7387\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">function createAnother(original) {\n    var clone = object(original);  \/\/ \u901a\u8fc7\u8c03\u7528\u51fd\u6570\u521b\u5efa\u4e00\u4e2a\u65b0\u5bf9\u8c61\n    clone.sayHi = function() {    \/\/ \u4ee5\u67d0\u79cd\u65b9\u5f0f\u6765\u589e\u5f3a\u8fd9\u4e2a\u5bf9\u8c61\n        alert(\"Hi\");\n    };\n    return clone;    \/\/ \u8fd4\u56de\u8fd9\u4e2a\u5bf9\u8c61<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"6%E5%AF%84%E7%94%9F%E7%BB%84%E5%90%88%E5%BC%8F%E7%BB%A7%E6%89%BF\"><\/span><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-red-color\">6.\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f<\/mark><span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u4e3a\u4e86\u89e3\u51b3\u7ec4\u5408\u7ee7\u627f\u9700\u8981\u521b\u5efa\u989d\u5916\u521b\u5efa\u7236\u7c7b\u539f\u578b\u5b9e\u4f8b\u548c\u6bcf\u4e2a\u5c5e\u6027\u5728\u7236\u7c7b\u5b9e\u4f8b\u548c\u5b50\u7c7b\u5b9e\u4f8b\u4e2d\u5747\u5b58\u5728\u4e00\u4efd\u7684\u95ee\u9898\uff0c\u53ef\u4ee5\u4f7f\u7528\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">            \r\n        function object(o){\r\n            function F(){}\r\n            F.prototype = o;\r\n            return new F();\r\n        }\r\n    \r\n        function inheritPrototype(subType, superType){\r\n            var prototype = object(superType.prototype);   \/\/create object\r\n            prototype.constructor = subType;               \/\/augment object\r\n            subType.prototype = prototype;                 \/\/assign object\r\n        }\r\n                                \r\n        function SuperType(name){\r\n            this.name = name;\r\n            this.colors = [\"red\", \"blue\", \"green\"];\r\n        }\r\n        \r\n        SuperType.prototype.sayName = function(){\r\n            alert(this.name);\r\n        };\r\n\r\n        function SubType(name, age){  \r\n            SuperType.call(this, name);\r\n            \r\n            this.age = age;\r\n        }\r\n\r\n        inheritPrototype(SubType, SuperType);\r\n        \r\n        SubType.prototype.sayAge = function(){\r\n            alert(this.age);\r\n        };\r\n        \r\n        var instance1 = new SubType(\"Nicholas\", 29);\r\n        instance1.colors.push(\"black\");\r\n        alert(instance1.colors);  \/\/\"red,blue,green,black\"\r\n        instance1.sayName();      \/\/\"Nicholas\";\r\n        instance1.sayAge();       \/\/29\r\n        \r\n       \r\n        var instance2 = new SubType(\"Greg\", 27);\r\n        alert(instance2.colors);  \/\/\"red,blue,green\"\r\n        instance2.sayName();      \/\/\"Greg\";\r\n        instance2.sayAge();       \/\/27<\/code><\/pre>\n\n\n\n<p>\u7b80\u5355\u5730\u8bf4\u5c31\u662f\u5148\u7ed9\u7236\u7c7b\u539f\u578b\u5bf9\u8c61\u521b\u5efa\u4e00\u4e2a\u62f7\u8d1d\uff0c\u7136\u540e\u628a\u8fd9\u4e2a\u62f7\u8d1d\u7684\u6784\u9020\u51fd\u6570\u6539\u6210\u5b50\u7c7b\u7684\u6784\u9020\u51fd\u6570\uff0c\u5e76\u5e76\u4e14\u628a\u8fd9\u4e2a\u62f7\u8d1d\u8d4b\u7ed9\u5b50\u7c7b\u7684\u539f\u578b\u5bf9\u8c61\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u7b2c6\u7ae0 \u9762\u5411\u5bf9\u8c61\u7684\u7a0b\u5e8f\u8bbe\u8ba1 ECMA-262\u628a\u5bf9\u8c61\u5b9a\u4e49\u4e3a\uff1a\u201c\u65e0\u5e8f\u5c5e\u6027\u7684\u96c6\u5408\uff0c\u5176\u5c5e\u6027\u53ef\u4ee5\u5305\u542b\u57fa\u672c\u503c\u3001\u5bf9\u8c61\u6216\u51fd\u6570\u201d\u3002 1.\u7406\u89e3\u5bf9\u8c61 \u521b\u5efa\u5bf9\u8c61\u65f6\u53ef\u4ee5\u901a\u8fc7new Object()\u6765\u521b\u5efa\uff0c\u4e5f\u53ef\u4ee5\u901a\u8fc7\u5b57\u9762\u91cf\u7684\u65b9\u5f0f&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10,6],"tags":[166],"class_list":["post-1455","post","type-post","status-publish","format-standard","hentry","category-10","category-6","tag-professionaljavascript"],"_links":{"self":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1455","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1455"}],"version-history":[{"count":26,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1455\/revisions"}],"predecessor-version":[{"id":1977,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1455\/revisions\/1977"}],"wp:attachment":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1455"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1455"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1455"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}