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href="/article/%E6%B7%B1%E5%85%A5Vue3%E6%BA%90%E7%A0%81%EF%BC%8C%E7%9C%8B%E7%9C%8BVue.use%E5%90%8E%E7%A9%B6%E7%AB%9F%E5%8F%91%E7%94%9F%E4%BA%86%E4%BB%80%E4%B9%88%EF%BC%9F.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>深入Vue3源码，看看Vue.use后究竟发生了什么？</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/article/%E6%B7%B1%E5%85%A5%E7%90%86%E8%A7%A3Proxy%E4%B8%8EReflect.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>深入理解Proxy与Reflect</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/article/%E6%B7%B1%E5%85%A5%E7%90%86%E8%A7%A3%E6%B5%8F%E8%A7%88%E5%99%A8%E7%BC%93%E5%AD%98%E6%9C%BA%E5%88%B6.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>深入理解浏览器缓存机制</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/article/%E6%B7%B1%E5%85%A5%E7%90%86%E8%A7%A3%E6%B5%8F%E8%A7%88%E5%99%A8%E8%BF%90%E8%A1%8C%E5%8E%9F%E7%90%86.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>深入理解浏览器运行原理</p><!--]--></a><!----></div><!----></div><!--]--></div></section></div><div class="group" data-v-0e1b55d4><section class="VPSidebarItem level-0 collapsible collapsed" data-v-0e1b55d4 data-v-4a3e3544><div class="item" role="button" tabindex="0" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><h2 class="text" data-v-4a3e3544>学习笔记</h2><div class="caret" role="button" aria-label="toggle section" tabindex="0" data-v-4a3e3544><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" 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class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/note/JavaScriptEnhanced.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>JavaScript进阶</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/note/Front-end%20Engineering.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>前端工程化</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/note/SSR.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>服务端渲染</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/note/React.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>React基础</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/note/React%20Hooks.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>React Hooks</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/note/Redux.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>Redux</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/note/React%20Router.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>React Router</p><!--]--></a><!----></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-4a3e3544 data-v-4a3e3544><div class="item" data-v-4a3e3544><div class="indicator" data-v-4a3e3544></div><a class="VPLink link link" href="/note/MySQL.html" data-v-4a3e3544><!--[--><p class="text" data-v-4a3e3544>MySQL</p><!--]--></a><!----></div><!----></div><!--]--></div></section></div><!--]--><!--[--><!--]--></nav></aside><div class="VPContent has-sidebar" id="VPContent" data-v-9d158fda data-v-585eef7d><div class="VPDoc has-sidebar has-aside" data-v-585eef7d data-v-a686a8a6><!--[--><!--]--><div class="container" data-v-a686a8a6><div class="aside" data-v-a686a8a6><div class="aside-curtain" data-v-a686a8a6></div><div class="aside-container" data-v-a686a8a6><div class="aside-content" data-v-a686a8a6><div class="VPDocAside" data-v-a686a8a6 data-v-31570b60><!--[--><!--]--><!--[--><!--]--><div class="VPDocAsideOutline" role="navigation" data-v-31570b60 data-v-ba8455b5><div class="content" data-v-ba8455b5><div class="outline-marker" data-v-ba8455b5></div><div class="outline-title" role="heading" aria-level="2" data-v-ba8455b5>On this page</div><nav aria-labelledby="doc-outline-aria-label" data-v-ba8455b5><span class="visually-hidden" id="doc-outline-aria-label" data-v-ba8455b5> Table of Contents for current page </span><ul class="root" data-v-ba8455b5 data-v-6713c9cc><!--[--><!--]--></ul></nav></div></div><!--[--><!--]--><div class="spacer" data-v-31570b60></div><!--[--><!--]--><!----><!--[--><!--]--><!--[--><!--]--></div></div></div></div><div class="content" data-v-a686a8a6><div class="content-container" data-v-a686a8a6><!--[--><!--]--><!----><main class="main" data-v-a686a8a6><div style="position:relative;" class="vp-doc _article_%E5%BD%BB%E5%BA%95%E6%90%9E%E6%87%82%E5%AF%B9%E8%B1%A1%E7%9A%84%E6%95%B0%E6%8D%AE%E5%B1%9E%E6%80%A7%E6%8F%8F%E8%BF%B0%E7%AC%A6%E3%80%81%E5%AD%98%E5%82%A8%E5%B1%9E%E6%80%A7%E6%8F%8F%E8%BF%B0%E7%AC%A6" data-v-a686a8a6><div><h1 id="彻底搞懂对象的数据属性描述符、存储属性描述符" tabindex="-1">彻底搞懂对象的数据属性描述符、存储属性描述符 <a class="header-anchor" href="#彻底搞懂对象的数据属性描述符、存储属性描述符" aria-label="Permalink to &quot;彻底搞懂对象的数据属性描述符、存储属性描述符&quot;">​</a></h1><h2 id="属性描述符" tabindex="-1">属性描述符 <a class="header-anchor" href="#属性描述符" aria-label="Permalink to &quot;属性描述符&quot;">​</a></h2><div class="language-js vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">js</span><pre class="shiki github-dark vp-code-dark"><code><span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#F97583;">let</span><span style="color:#E1E4E8;"> obj </span><span style="color:#F97583;">=</span><span style="color:#E1E4E8;"> {</span></span>
<span class="line"><span style="color:#E1E4E8;"> name: </span><span style="color:#9ECBFF;">&quot;ziu&quot;</span><span style="color:#E1E4E8;">,</span></span>
<span class="line"><span style="color:#E1E4E8;"> age: </span><span style="color:#79B8FF;">18</span></span>
<span class="line"><span style="color:#E1E4E8;"> }</span></span>
<span class="line"><span style="color:#E1E4E8;"> Object.</span><span style="color:#B392F0;">defineProperty</span><span style="color:#E1E4E8;">(obj, </span><span style="color:#9ECBFF;">&quot;height&quot;</span><span style="color:#E1E4E8;">, {</span></span>
<span class="line"><span style="color:#E1E4E8;"> value: </span><span style="color:#79B8FF;">1.88</span></span>
<span class="line"><span style="color:#E1E4E8;"> })</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(obj) </span><span style="color:#6A737D;">// { name: &#39;ziu&#39;, age: 18 }</span></span></code></pre><pre class="shiki github-light vp-code-light"><code><span class="line"><span style="color:#24292E;"> </span><span style="color:#D73A49;">let</span><span style="color:#24292E;"> obj </span><span style="color:#D73A49;">=</span><span style="color:#24292E;"> {</span></span>
<span class="line"><span style="color:#24292E;"> name: </span><span style="color:#032F62;">&quot;ziu&quot;</span><span style="color:#24292E;">,</span></span>
<span class="line"><span style="color:#24292E;"> age: </span><span style="color:#005CC5;">18</span></span>
<span class="line"><span style="color:#24292E;"> }</span></span>
<span class="line"><span style="color:#24292E;"> Object.</span><span style="color:#6F42C1;">defineProperty</span><span style="color:#24292E;">(obj, </span><span style="color:#032F62;">&quot;height&quot;</span><span style="color:#24292E;">, {</span></span>
<span class="line"><span style="color:#24292E;"> value: </span><span style="color:#005CC5;">1.88</span></span>
<span class="line"><span style="color:#24292E;"> })</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(obj) </span><span style="color:#6A737D;">// { name: &#39;ziu&#39;, age: 18 }</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br></div></div><p><code>obj</code>对象的控制台输出中，并没有<code>defineProperty</code>新定义的<code>height</code>，这是因为不可枚举的（不可遍历的），在打印时并没有和其他属性一起输出。这个属性已经被添加到对象中，只不过不可见。</p><div class="language-js vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">js</span><pre class="shiki github-dark vp-code-dark"><code><span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(obj.height) </span><span style="color:#6A737D;">// 1.88</span></span></code></pre><pre class="shiki github-light vp-code-light"><code><span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(obj.height) </span><span style="color:#6A737D;">// 1.88</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br></div></div><p>属性描述符是一个对象，根据功能不同，可以分为两类：<strong>数据属性描述符</strong>和<strong>存储属性描述符</strong></p><h3 id="数据属性描述符" tabindex="-1">数据属性描述符 <a class="header-anchor" href="#数据属性描述符" aria-label="Permalink to &quot;数据属性描述符&quot;">​</a></h3><ul><li>数据属性描述符（Data Properties） <ul><li><code>value</code>该属性对应的值，默认<code>undefined</code></li><li><code>configurable</code>该属性描述符是否可被改变、是否可被删除，默认为<code>false</code></li><li><code>enumerable</code>该属性是否可被枚举，默认为<code>false</code></li><li><code>writable</code>该属性是否可以被写入新的值，默认为<code>false</code></li></ul></li></ul><p><strong>没有用属性描述符定义的对象属性（直接使用<code>.</code>语法）</strong>，也是具有以上属性描述符的特性的，<code>value</code>值为属性被赋值的值，其他<code>configurable</code>、<code>emumerable</code>、<code>writable</code>默认值都为<code>true</code>。<strong>注意，属性描述符区全为小写。</strong></p><div class="language-js vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">js</span><pre class="shiki github-dark vp-code-dark"><code><span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#F97583;">let</span><span style="color:#E1E4E8;"> obj </span><span style="color:#F97583;">=</span><span style="color:#E1E4E8;"> {</span></span>
<span class="line"><span style="color:#E1E4E8;"> name: </span><span style="color:#9ECBFF;">&quot;ziu&quot;</span><span style="color:#E1E4E8;">,</span></span>
<span class="line"><span style="color:#E1E4E8;"> age: </span><span style="color:#79B8FF;">18</span></span>
<span class="line"><span style="color:#E1E4E8;"> }</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// 数据属性描述符</span></span>
<span class="line"><span style="color:#E1E4E8;"> Object.</span><span style="color:#B392F0;">defineProperty</span><span style="color:#E1E4E8;">(obj, </span><span style="color:#9ECBFF;">&quot;address&quot;</span><span style="color:#E1E4E8;">, {</span></span>
<span class="line"><span style="color:#E1E4E8;"> value: </span><span style="color:#9ECBFF;">&quot;Beijing&quot;</span><span style="color:#E1E4E8;">, </span><span style="color:#6A737D;">// 该属性对应的值，默认为undefine</span></span>
<span class="line"><span style="color:#E1E4E8;"> configurable: </span><span style="color:#79B8FF;">false</span><span style="color:#E1E4E8;">, </span><span style="color:#6A737D;">// 该属性描述符是否可被改变、是否可被删除，默认为false</span></span>
<span class="line"><span style="color:#E1E4E8;"> enumerable: </span><span style="color:#79B8FF;">true</span><span style="color:#E1E4E8;">, </span><span style="color:#6A737D;">// 该属性是否可被枚举，默认为false</span></span>
<span class="line"><span style="color:#E1E4E8;"> writable: </span><span style="color:#79B8FF;">true</span><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// 该属性是否可以被写入新的值，默认为false</span></span>
<span class="line"><span style="color:#E1E4E8;"> })</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// configurable</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#F97583;">delete</span><span style="color:#E1E4E8;"> obj.address</span></span>
<span class="line"><span style="color:#E1E4E8;"> obj.address </span><span style="color:#F97583;">=</span><span style="color:#E1E4E8;"> </span><span style="color:#9ECBFF;">&quot;Shanghai&quot;</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(obj.address) </span><span style="color:#6A737D;">// Beijing</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// enumerable</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(obj)</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#F97583;">for</span><span style="color:#E1E4E8;">(</span><span style="color:#F97583;">let</span><span style="color:#E1E4E8;"> key </span><span style="color:#F97583;">in</span><span style="color:#E1E4E8;"> obj) {</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(key)</span></span>
<span class="line"><span style="color:#E1E4E8;"> }</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(Object.</span><span style="color:#B392F0;">keys</span><span style="color:#E1E4E8;">(obj))</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// writable</span></span>
<span class="line"><span style="color:#E1E4E8;"> obj.address </span><span style="color:#F97583;">=</span><span style="color:#E1E4E8;"> </span><span style="color:#9ECBFF;">&quot;Tianjin&quot;</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(obj.address)</span></span></code></pre><pre class="shiki github-light vp-code-light"><code><span class="line"><span style="color:#24292E;"> </span><span style="color:#D73A49;">let</span><span style="color:#24292E;"> obj </span><span style="color:#D73A49;">=</span><span style="color:#24292E;"> {</span></span>
<span class="line"><span style="color:#24292E;"> name: </span><span style="color:#032F62;">&quot;ziu&quot;</span><span style="color:#24292E;">,</span></span>
<span class="line"><span style="color:#24292E;"> age: </span><span style="color:#005CC5;">18</span></span>
<span class="line"><span style="color:#24292E;"> }</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6A737D;">// 数据属性描述符</span></span>
<span class="line"><span style="color:#24292E;"> Object.</span><span style="color:#6F42C1;">defineProperty</span><span style="color:#24292E;">(obj, </span><span style="color:#032F62;">&quot;address&quot;</span><span style="color:#24292E;">, {</span></span>
<span class="line"><span style="color:#24292E;"> value: </span><span style="color:#032F62;">&quot;Beijing&quot;</span><span style="color:#24292E;">, </span><span style="color:#6A737D;">// 该属性对应的值，默认为undefine</span></span>
<span class="line"><span style="color:#24292E;"> configurable: </span><span style="color:#005CC5;">false</span><span style="color:#24292E;">, </span><span style="color:#6A737D;">// 该属性描述符是否可被改变、是否可被删除，默认为false</span></span>
<span class="line"><span style="color:#24292E;"> enumerable: </span><span style="color:#005CC5;">true</span><span style="color:#24292E;">, </span><span style="color:#6A737D;">// 该属性是否可被枚举，默认为false</span></span>
<span class="line"><span style="color:#24292E;"> writable: </span><span style="color:#005CC5;">true</span><span style="color:#24292E;"> </span><span style="color:#6A737D;">// 该属性是否可以被写入新的值，默认为false</span></span>
<span class="line"><span style="color:#24292E;"> })</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6A737D;">// configurable</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#D73A49;">delete</span><span style="color:#24292E;"> obj.address</span></span>
<span class="line"><span style="color:#24292E;"> obj.address </span><span style="color:#D73A49;">=</span><span style="color:#24292E;"> </span><span style="color:#032F62;">&quot;Shanghai&quot;</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(obj.address) </span><span style="color:#6A737D;">// Beijing</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6A737D;">// enumerable</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(obj)</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#D73A49;">for</span><span style="color:#24292E;">(</span><span style="color:#D73A49;">let</span><span style="color:#24292E;"> key </span><span style="color:#D73A49;">in</span><span style="color:#24292E;"> obj) {</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(key)</span></span>
<span class="line"><span style="color:#24292E;"> }</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(Object.</span><span style="color:#6F42C1;">keys</span><span style="color:#24292E;">(obj))</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6A737D;">// writable</span></span>
<span class="line"><span style="color:#24292E;"> obj.address </span><span style="color:#D73A49;">=</span><span style="color:#24292E;"> </span><span style="color:#032F62;">&quot;Tianjin&quot;</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(obj.address)</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br></div></div><h3 id="存储属性描述符" tabindex="-1">存储属性描述符 <a class="header-anchor" href="#存储属性描述符" aria-label="Permalink to &quot;存储属性描述符&quot;">​</a></h3><ul><li>存储属性描述符（Accessor Properties） <ul><li><code>get</code>当访问该属性时，会调用此函数，默认为<code>undefined</code>。</li><li><code>set</code>当属性值被修改时，会调用此函数，默认为<code>undefined</code>。</li></ul></li></ul><p>注意，<code>get</code>、<code>set</code>描述符与<code>vaule</code>、<code>writable</code>描述符不共存。</p><table><thead><tr><th></th><th><code>configurable</code></th><th><code>enumerable</code></th><th><code>value</code></th><th><code>writable</code></th><th><code>get</code></th><th><code>set</code></th></tr></thead><tbody><tr><td>数据描述符</td><td>可以</td><td>可以</td><td>可以</td><td>可以</td><td><strong>不可以</strong></td><td><strong>不可以</strong></td></tr><tr><td>存取描述符</td><td>可以</td><td>可以</td><td><strong>不可以</strong></td><td><strong>不可以</strong></td><td>可以</td><td>可以</td></tr></tbody></table><div class="language-js vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">js</span><pre class="shiki github-dark vp-code-dark"><code><span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#F97583;">let</span><span style="color:#E1E4E8;"> obj </span><span style="color:#F97583;">=</span><span style="color:#E1E4E8;"> {</span></span>
<span class="line"><span style="color:#E1E4E8;"> name: </span><span style="color:#9ECBFF;">&quot;ziu&quot;</span><span style="color:#E1E4E8;">,</span></span>
<span class="line"><span style="color:#E1E4E8;"> age: </span><span style="color:#79B8FF;">18</span><span style="color:#E1E4E8;">,</span></span>
<span class="line"><span style="color:#E1E4E8;"> _address: </span><span style="color:#9ECBFF;">&quot;Beijing&quot;</span></span>
<span class="line"><span style="color:#E1E4E8;"> }</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// Accessor Properties</span></span>
<span class="line"><span style="color:#E1E4E8;"> Object.</span><span style="color:#B392F0;">defineProperty</span><span style="color:#E1E4E8;">(obj, </span><span style="color:#9ECBFF;">&quot;address&quot;</span><span style="color:#E1E4E8;">, {</span></span>
<span class="line"><span style="color:#E1E4E8;"> enumerable: </span><span style="color:#79B8FF;">true</span><span style="color:#E1E4E8;">,</span></span>
<span class="line"><span style="color:#E1E4E8;"> configurable: </span><span style="color:#79B8FF;">true</span><span style="color:#E1E4E8;">,</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// value: &quot;Beijing&quot;,</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// writable: true,</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#B392F0;">get</span><span style="color:#E1E4E8;">: </span><span style="color:#F97583;">function</span><span style="color:#E1E4E8;">() {</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#F97583;">return</span><span style="color:#E1E4E8;"> </span><span style="color:#79B8FF;">this</span><span style="color:#E1E4E8;">._address</span></span>
<span class="line"><span style="color:#E1E4E8;"> },</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#B392F0;">set</span><span style="color:#E1E4E8;">: </span><span style="color:#F97583;">function</span><span style="color:#E1E4E8;">(</span><span style="color:#FFAB70;">val</span><span style="color:#E1E4E8;">) {</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#79B8FF;">this</span><span style="color:#E1E4E8;">._address </span><span style="color:#F97583;">=</span><span style="color:#E1E4E8;"> val</span></span>
<span class="line"><span style="color:#E1E4E8;"> }</span></span>
<span class="line"><span style="color:#E1E4E8;"> })</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(obj.address) </span><span style="color:#6A737D;">// 调用getter() Beijing</span></span>
<span class="line"><span style="color:#E1E4E8;"> obj.address </span><span style="color:#F97583;">=</span><span style="color:#E1E4E8;"> </span><span style="color:#9ECBFF;">&quot;Shanghai&quot;</span><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// 调用setter()</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(obj._address) </span><span style="color:#6A737D;">// Shanghai</span></span></code></pre><pre class="shiki github-light vp-code-light"><code><span class="line"><span style="color:#24292E;"> </span><span style="color:#D73A49;">let</span><span style="color:#24292E;"> obj </span><span style="color:#D73A49;">=</span><span style="color:#24292E;"> {</span></span>
<span class="line"><span style="color:#24292E;"> name: </span><span style="color:#032F62;">&quot;ziu&quot;</span><span style="color:#24292E;">,</span></span>
<span class="line"><span style="color:#24292E;"> age: </span><span style="color:#005CC5;">18</span><span style="color:#24292E;">,</span></span>
<span class="line"><span style="color:#24292E;"> _address: </span><span style="color:#032F62;">&quot;Beijing&quot;</span></span>
<span class="line"><span style="color:#24292E;"> }</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6A737D;">// Accessor Properties</span></span>
<span class="line"><span style="color:#24292E;"> Object.</span><span style="color:#6F42C1;">defineProperty</span><span style="color:#24292E;">(obj, </span><span style="color:#032F62;">&quot;address&quot;</span><span style="color:#24292E;">, {</span></span>
<span class="line"><span style="color:#24292E;"> enumerable: </span><span style="color:#005CC5;">true</span><span style="color:#24292E;">,</span></span>
<span class="line"><span style="color:#24292E;"> configurable: </span><span style="color:#005CC5;">true</span><span style="color:#24292E;">,</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6A737D;">// value: &quot;Beijing&quot;,</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6A737D;">// writable: true,</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6F42C1;">get</span><span style="color:#24292E;">: </span><span style="color:#D73A49;">function</span><span style="color:#24292E;">() {</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#D73A49;">return</span><span style="color:#24292E;"> </span><span style="color:#005CC5;">this</span><span style="color:#24292E;">._address</span></span>
<span class="line"><span style="color:#24292E;"> },</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6F42C1;">set</span><span style="color:#24292E;">: </span><span style="color:#D73A49;">function</span><span style="color:#24292E;">(</span><span style="color:#E36209;">val</span><span style="color:#24292E;">) {</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#005CC5;">this</span><span style="color:#24292E;">._address </span><span style="color:#D73A49;">=</span><span style="color:#24292E;"> val</span></span>
<span class="line"><span style="color:#24292E;"> }</span></span>
<span class="line"><span style="color:#24292E;"> })</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(obj.address) </span><span style="color:#6A737D;">// 调用getter() Beijing</span></span>
<span class="line"><span style="color:#24292E;"> obj.address </span><span style="color:#D73A49;">=</span><span style="color:#24292E;"> </span><span style="color:#032F62;">&quot;Shanghai&quot;</span><span style="color:#24292E;"> </span><span style="color:#6A737D;">// 调用setter()</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(obj._address) </span><span style="color:#6A737D;">// Shanghai</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br></div></div><h3 id="应用场景" tabindex="-1">应用场景 <a class="header-anchor" href="#应用场景" aria-label="Permalink to &quot;应用场景&quot;">​</a></h3><ol><li>隐藏某个私有属性，希望直接被外界使用和赋值。（下划线开头的变量一般为私有属性）</li><li>获取某个属性被访问或赋值的时刻，可以设置伴随被访问或被赋值时，执行其他函数。</li></ol><div class="language-js vp-adaptive-theme line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">js</span><pre class="shiki github-dark vp-code-dark"><code><span class="line"><span style="color:#E1E4E8;"> Object.</span><span style="color:#B392F0;">defineProperty</span><span style="color:#E1E4E8;">(obj, </span><span style="color:#9ECBFF;">&quot;address&quot;</span><span style="color:#E1E4E8;">, {</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#B392F0;">get</span><span style="color:#E1E4E8;">: </span><span style="color:#F97583;">function</span><span style="color:#E1E4E8;">() {</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#B392F0;">bar</span><span style="color:#E1E4E8;">()</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#F97583;">return</span><span style="color:#E1E4E8;"> </span><span style="color:#79B8FF;">this</span><span style="color:#E1E4E8;">._address</span></span>
<span class="line"><span style="color:#E1E4E8;"> },</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#B392F0;">set</span><span style="color:#E1E4E8;">: </span><span style="color:#F97583;">function</span><span style="color:#E1E4E8;">(</span><span style="color:#FFAB70;">val</span><span style="color:#E1E4E8;">) {</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#B392F0;">foo</span><span style="color:#E1E4E8;">()</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#79B8FF;">this</span><span style="color:#E1E4E8;">._address </span><span style="color:#F97583;">=</span><span style="color:#E1E4E8;"> val</span></span>
<span class="line"><span style="color:#E1E4E8;"> }</span></span>
<span class="line"><span style="color:#E1E4E8;"> })</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(obj.address) </span><span style="color:#6A737D;">// got address value once</span></span>
<span class="line"><span style="color:#E1E4E8;"> obj.address </span><span style="color:#F97583;">=</span><span style="color:#E1E4E8;"> </span><span style="color:#9ECBFF;">&quot;Shanghai&quot;</span><span style="color:#E1E4E8;"> </span><span style="color:#6A737D;">// resetted address value once</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#F97583;">function</span><span style="color:#E1E4E8;"> </span><span style="color:#B392F0;">bar</span><span style="color:#E1E4E8;">() {</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(</span><span style="color:#9ECBFF;">&quot;got address value once&quot;</span><span style="color:#E1E4E8;">)</span></span>
<span class="line"><span style="color:#E1E4E8;"> }</span></span>
<span class="line"><span style="color:#E1E4E8;"> </span><span style="color:#F97583;">function</span><span style="color:#E1E4E8;"> </span><span style="color:#B392F0;">foo</span><span style="color:#E1E4E8;">() {</span></span>
<span class="line"><span style="color:#E1E4E8;"> console.</span><span style="color:#B392F0;">log</span><span style="color:#E1E4E8;">(</span><span style="color:#9ECBFF;">&quot;resetted address value once&quot;</span><span style="color:#E1E4E8;">)</span></span>
<span class="line"><span style="color:#E1E4E8;"> }</span></span></code></pre><pre class="shiki github-light vp-code-light"><code><span class="line"><span style="color:#24292E;"> Object.</span><span style="color:#6F42C1;">defineProperty</span><span style="color:#24292E;">(obj, </span><span style="color:#032F62;">&quot;address&quot;</span><span style="color:#24292E;">, {</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6F42C1;">get</span><span style="color:#24292E;">: </span><span style="color:#D73A49;">function</span><span style="color:#24292E;">() {</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6F42C1;">bar</span><span style="color:#24292E;">()</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#D73A49;">return</span><span style="color:#24292E;"> </span><span style="color:#005CC5;">this</span><span style="color:#24292E;">._address</span></span>
<span class="line"><span style="color:#24292E;"> },</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6F42C1;">set</span><span style="color:#24292E;">: </span><span style="color:#D73A49;">function</span><span style="color:#24292E;">(</span><span style="color:#E36209;">val</span><span style="color:#24292E;">) {</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#6F42C1;">foo</span><span style="color:#24292E;">()</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#005CC5;">this</span><span style="color:#24292E;">._address </span><span style="color:#D73A49;">=</span><span style="color:#24292E;"> val</span></span>
<span class="line"><span style="color:#24292E;"> }</span></span>
<span class="line"><span style="color:#24292E;"> })</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(obj.address) </span><span style="color:#6A737D;">// got address value once</span></span>
<span class="line"><span style="color:#24292E;"> obj.address </span><span style="color:#D73A49;">=</span><span style="color:#24292E;"> </span><span style="color:#032F62;">&quot;Shanghai&quot;</span><span style="color:#24292E;"> </span><span style="color:#6A737D;">// resetted address value once</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#D73A49;">function</span><span style="color:#24292E;"> </span><span style="color:#6F42C1;">bar</span><span style="color:#24292E;">() {</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(</span><span style="color:#032F62;">&quot;got address value once&quot;</span><span style="color:#24292E;">)</span></span>
<span class="line"><span style="color:#24292E;"> }</span></span>
<span class="line"><span style="color:#24292E;"> </span><span style="color:#D73A49;">function</span><span style="color:#24292E;"> </span><span style="color:#6F42C1;">foo</span><span style="color:#24292E;">() {</span></span>
<span class="line"><span style="color:#24292E;"> console.</span><span style="color:#6F42C1;">log</span><span style="color:#24292E;">(</span><span style="color:#032F62;">&quot;resetted address value once&quot;</span><span style="color:#24292E;">)</span></span>
<span class="line"><span style="color:#24292E;"> }</span></span></code></pre><div class="line-numbers-wrapper" aria-hidden="true"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br></div></div></div></div></main><footer class="VPDocFooter" data-v-a686a8a6 data-v-0b8e2cba><!--[--><!--]--><div class="edit-info" data-v-0b8e2cba><div class="edit-link" data-v-0b8e2cba><a class="VPLink link vp-external-link-icon no-icon edit-link-button" href="https://github.com/ZiuChen/ZiuChen.github.io/edit/main/docs/article/彻底搞懂对象的数据属性描述符、存储属性描述符.md" target="_blank" rel="noreferrer" data-v-0b8e2cba><!--[--><svg xmlns="http://www.w3.org/2000/svg" viewbox="0 0 24 24" class="edit-link-icon" aria-label="edit icon" data-v-0b8e2cba><path d="M18,23H4c-1.7,0-3-1.3-3-3V6c0-1.7,1.3-3,3-3h7c0.6,0,1,0.4,1,1s-0.4,1-1,1H4C3.4,5,3,5.4,3,6v14c0,0.6,0.4,1,1,1h14c0.6,0,1-0.4,1-1v-7c0-0.6,0.4-1,1-1s1,0.4,1,1v7C21,21.7,19.7,23,18,23z"></path><path d="M8,17c-0.3,0-0.5-0.1-0.7-0.3C7,16.5,6.9,16.1,7,15.8l1-4c0-0.2,0.1-0.3,0.3-0.5l9.5-9.5c1.2-1.2,3.2-1.2,4.4,0c1.2,1.2,1.2,3.2,0,4.4l-9.5,9.5c-0.1,0.1-0.3,0.2-0.5,0.3l-4,1C8.2,17,8.1,17,8,17zM9.9,12.5l-0.5,2.1l2.1-0.5l9.3-9.3c0.4-0.4,0.4-1.1,0-1.6c-0.4-0.4-1.2-0.4-1.6,0l0,0L9.9,12.5z M18.5,2.5L18.5,2.5L18.5,2.5z"></path></svg> Edit this page on GitHub<!--]--></a></div><div class="last-updated" data-v-0b8e2cba><p class="VPLastUpdated" data-v-0b8e2cba data-v-a6f11a31>Updated Date: <time datetime="2024-01-06T06:57:39.000Z" data-v-a6f11a31></time></p></div></div><nav class="prev-next" data-v-0b8e2cba><div class="pager" data-v-0b8e2cba><a class="pager-link prev" href="/article/%E4%BB%8E0%E5%AE%9E%E7%8E%B0%E4%B8%80%E4%B8%AA%E5%B9%B4%E5%BA%A6%E6%8A%A5%E5%91%8A.html" data-v-0b8e2cba><span class="desc" data-v-0b8e2cba>Previous page</span><span class="title" data-v-0b8e2cba>从0实现一个年度报告</span></a></div><div class="pager" data-v-0b8e2cba><a class="pager-link next" href="/article/%E6%B5%85%E6%9E%90defineProperty%E4%B8%8EProxy%E5%AE%9E%E7%8E%B0%E7%9A%84%E5%8F%8C%E5%90%91%E7%BB%91%E5%AE%9A.html" data-v-0b8e2cba><span class="desc" data-v-0b8e2cba>Next page</span><span class="title" data-v-0b8e2cba>浅析defineProperty与Proxy实现的双向绑定</span></a></div></nav></footer><!--[--><!--]--></div></div></div><!--[--><!--]--></div></div><footer class="VPFooter has-sidebar" data-v-9d158fda data-v-2c80950a><div class="container" data-v-2c80950a><p class="message" data-v-2c80950a>Released under the MIT License.</p><p class="copyright" data-v-2c80950a>Copyright © 2019-present Ziu Chen</p></div></footer><!--[--><!--]--></div></div>
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