study/ZiuChen.github.io
1
0
Fork 0
mirror of https://github.com/ZiuChen/ZiuChen.github.io.git synced 2025-08-18 23:49:33 +08:00
Code Issues Packages Projects Releases Wiki Activity
ZiuChen.github.io/note/React.html

674 lines
267 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html>
<html lang="en-US" dir="ltr">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>React | ZiuChen</title>
<meta name="description" content="Unlimited Progress.">
<link rel="preload stylesheet" href="/assets/style.edafdec9.css" as="style">
<link rel="modulepreload" href="/assets/chunks/VPAlgoliaSearchBox.107ab7ad.js">
<link rel="modulepreload" href="/assets/app.ab8d0b9f.js">
<link rel="modulepreload" href="/assets/note_React.md.7e023574.lean.js">
<link rel="icon" href="/logo.png">
<script id="check-dark-light">(()=>{const e=localStorage.getItem("vitepress-theme-appearance")||"",a=window.matchMedia("(prefers-color-scheme: dark)").matches;(!e||e==="auto"?a:e==="dark")&&document.documentElement.classList.add("dark")})();</script>
</head>
<body>
<div id="app"><div class="Layout" data-v-3af881ed><!--[--><!--]--><!--[--><span tabindex="-1" data-v-00bddfc0></span><a href="#VPContent" class="VPSkipLink visually-hidden" data-v-00bddfc0> Skip to content </a><!--]--><!----><header class="VPNav" data-v-3af881ed data-v-3796071a><div class="VPNavBar has-sidebar" data-v-3796071a data-v-fe00b0e5><div class="container" data-v-fe00b0e5><div class="title" data-v-fe00b0e5><div class="VPNavBarTitle has-sidebar" data-v-fe00b0e5 data-v-a7f91dcc><a class="title" href="/" data-v-a7f91dcc><!--[--><!--]--><!--[--><img class="VPImage logo" src="/logo.png" alt data-v-dca92699><!--]--><!--[-->ZiuChen<!--]--><!--[--><!--]--></a></div></div><div class="content" data-v-fe00b0e5><div class="curtain" data-v-fe00b0e5></div><div class="content-body" data-v-fe00b0e5><!--[--><!--]--><div class="VPNavBarSearch search" data-v-fe00b0e5 style="--6dc8a562:&#39;Meta&#39;;"><div id="docsearch"><button type="button" class="DocSearch DocSearch-Button" aria-label="Search"><span class="DocSearch-Button-Container"><svg class="DocSearch-Search-Icon" width="20" height="20" viewBox="0 0 20 20"><path d="M14.386 14.386l4.0877 4.0877-4.0877-4.0877c-2.9418 2.9419-7.7115 2.9419-10.6533 0-2.9419-2.9418-2.9419-7.7115 0-10.6533 2.9418-2.9419 7.7115-2.9419 10.6533 0 2.9419 2.9418 2.9419 7.7115 0 10.6533z" stroke="currentColor" fill="none" fill-rule="evenodd" stroke-linecap="round" stroke-linejoin="round"></path></svg><span class="DocSearch-Button-Placeholder">Search</span></span><span class="DocSearch-Button-Keys"><kbd class="DocSearch-Button-Key"></kbd><kbd class="DocSearch-Button-Key">K</kbd></span></button></div></div><nav aria-labelledby="main-nav-aria-label" class="VPNavBarMenu menu" data-v-fe00b0e5 data-v-a4f7fa5c><span id="main-nav-aria-label" class="visually-hidden" data-v-a4f7fa5c>Main Navigation</span><!--[--><!--[--><a class="VPLink link VPNavBarMenuLink" href="/" data-v-a4f7fa5c data-v-1a106a35 data-v-8dd200cc><!--[-->首页<!--]--><!----></a><!--]--><!--[--><div class="VPFlyout VPNavBarMenuGroup" data-v-a4f7fa5c data-v-e76b733c><button type="button" class="button" aria-haspopup="true" aria-expanded="false" data-v-e76b733c><span class="text" data-v-e76b733c><!----> 我的项目 <svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="text-icon" data-v-e76b733c><path d="M12,16c-0.3,0-0.5-0.1-0.7-0.3l-6-6c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l5.3,5.3l5.3-5.3c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-6,6C12.5,15.9,12.3,16,12,16z"></path></svg></span></button><div class="menu" data-v-e76b733c><div class="VPMenu" data-v-e76b733c data-v-faf23071><div class="items" data-v-faf23071><!--[--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/project/ClipboardManager/" data-v-c0d2d58e data-v-8dd200cc><!--[-->超级剪贴板<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/project/Markdown/" data-v-c0d2d58e data-v-8dd200cc><!--[-->超级Markdown<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/project/SmartWordBreak/" data-v-c0d2d58e data-v-8dd200cc><!--[-->超级分词<!--]--><!----></a></div><!--]--><!--]--></div><!--[--><!--]--></div></div></div><!--]--><!--[--><div class="VPFlyout VPNavBarMenuGroup" data-v-a4f7fa5c data-v-e76b733c><button type="button" class="button" aria-haspopup="true" aria-expanded="false" data-v-e76b733c><span class="text" data-v-e76b733c><!----> 开源作品 <svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="text-icon" data-v-e76b733c><path d="M12,16c-0.3,0-0.5-0.1-0.7-0.3l-6-6c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l5.3,5.3l5.3-5.3c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-6,6C12.5,15.9,12.3,16,12,16z"></path></svg></span></button><div class="menu" data-v-e76b733c><div class="VPMenu" data-v-e76b733c data-v-faf23071><div class="items" data-v-faf23071><!--[--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/works/opensource.html" data-v-c0d2d58e data-v-8dd200cc><!--[-->个人作品<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/works/contribution.html" data-v-c0d2d58e data-v-8dd200cc><!--[-->社区贡献<!--]--><!----></a></div><!--]--><!--]--></div><!--[--><!--]--></div></div></div><!--]--><!--[--><div class="VPFlyout VPNavBarMenuGroup" data-v-a4f7fa5c data-v-e76b733c><button type="button" class="button" aria-haspopup="true" aria-expanded="false" data-v-e76b733c><span class="text" data-v-e76b733c><!----> 学习笔记 <svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="text-icon" data-v-e76b733c><path d="M12,16c-0.3,0-0.5-0.1-0.7-0.3l-6-6c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l5.3,5.3l5.3-5.3c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-6,6C12.5,15.9,12.3,16,12,16z"></path></svg></span></button><div class="menu" data-v-e76b733c><div class="VPMenu" data-v-e76b733c data-v-faf23071><div class="items" data-v-faf23071><!--[--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/note/JavaScript.html" data-v-c0d2d58e data-v-8dd200cc><!--[-->JavaScript基础<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/note/CSS.html" data-v-c0d2d58e data-v-8dd200cc><!--[-->CSS基础<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/note/JavaScriptEnhanced.html" data-v-c0d2d58e data-v-8dd200cc><!--[-->JavaScript进阶<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/note/Front-end%20Engineering.html" data-v-c0d2d58e data-v-8dd200cc><!--[-->前端工程化<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-faf23071 data-v-c0d2d58e><a class="VPLink link" href="/note/SSR.html" data-v-c0d2d58e data-v-8dd200cc><!--[-->服务端渲染<!--]--><!----></a></div><!--]--><!--]--></div><!--[--><!--]--></div></div></div><!--]--><!--[--><a class="VPLink link VPNavBarMenuLink" href="/self/" data-v-a4f7fa5c data-v-1a106a35 data-v-8dd200cc><!--[-->个人介绍<!--]--><!----></a><!--]--><!--]--></nav><!----><div class="VPNavBarAppearance appearance" data-v-fe00b0e5 data-v-2d4753dd><button class="VPSwitch VPSwitchAppearance" type="button" role="switch" aria-label="toggle dark mode" aria-checked="false" data-v-2d4753dd data-v-867372a0 data-v-dc009bc3><span class="check" data-v-dc009bc3><span class="icon" data-v-dc009bc3><!--[--><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="sun" data-v-867372a0><path d="M12,18c-3.3,0-6-2.7-6-6s2.7-6,6-6s6,2.7,6,6S15.3,18,12,18zM12,8c-2.2,0-4,1.8-4,4c0,2.2,1.8,4,4,4c2.2,0,4-1.8,4-4C16,9.8,14.2,8,12,8z"></path><path d="M12,4c-0.6,0-1-0.4-1-1V1c0-0.6,0.4-1,1-1s1,0.4,1,1v2C13,3.6,12.6,4,12,4z"></path><path d="M12,24c-0.6,0-1-0.4-1-1v-2c0-0.6,0.4-1,1-1s1,0.4,1,1v2C13,23.6,12.6,24,12,24z"></path><path d="M5.6,6.6c-0.3,0-0.5-0.1-0.7-0.3L3.5,4.9c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l1.4,1.4c0.4,0.4,0.4,1,0,1.4C6.2,6.5,5.9,6.6,5.6,6.6z"></path><path d="M19.8,20.8c-0.3,0-0.5-0.1-0.7-0.3l-1.4-1.4c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l1.4,1.4c0.4,0.4,0.4,1,0,1.4C20.3,20.7,20,20.8,19.8,20.8z"></path><path d="M3,13H1c-0.6,0-1-0.4-1-1s0.4-1,1-1h2c0.6,0,1,0.4,1,1S3.6,13,3,13z"></path><path d="M23,13h-2c-0.6,0-1-0.4-1-1s0.4-1,1-1h2c0.6,0,1,0.4,1,1S23.6,13,23,13z"></path><path d="M4.2,20.8c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l1.4-1.4c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-1.4,1.4C4.7,20.7,4.5,20.8,4.2,20.8z"></path><path d="M18.4,6.6c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l1.4-1.4c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-1.4,1.4C18.9,6.5,18.6,6.6,18.4,6.6z"></path></svg><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="moon" data-v-867372a0><path d="M12.1,22c-0.3,0-0.6,0-0.9,0c-5.5-0.5-9.5-5.4-9-10.9c0.4-4.8,4.2-8.6,9-9c0.4,0,0.8,0.2,1,0.5c0.2,0.3,0.2,0.8-0.1,1.1c-2,2.7-1.4,6.4,1.3,8.4c2.1,1.6,5,1.6,7.1,0c0.3-0.2,0.7-0.3,1.1-0.1c0.3,0.2,0.5,0.6,0.5,1c-0.2,2.7-1.5,5.1-3.6,6.8C16.6,21.2,14.4,22,12.1,22zM9.3,4.4c-2.9,1-5,3.6-5.2,6.8c-0.4,4.4,2.8,8.3,7.2,8.7c2.1,0.2,4.2-0.4,5.8-1.8c1.1-0.9,1.9-2.1,2.4-3.4c-2.5,0.9-5.3,0.5-7.5-1.1C9.2,11.4,8.1,7.7,9.3,4.4z"></path></svg><!--]--></span></span></button></div><div class="VPSocialLinks VPNavBarSocialLinks social-links" data-v-fe00b0e5 data-v-f0005c73 data-v-819d8281><!--[--><a class="VPSocialLink" href="https://github.com/ZiuChen" target="_blank" rel="noopener" data-v-819d8281 data-v-ba84061a><svg role="img" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><title>GitHub</title><path d="M12 .297c-6.63 0-12 5.373-12 12 0 5.303 3.438 9.8 8.205 11.385.6.113.82-.258.82-.577 0-.285-.01-1.04-.015-2.04-3.338.724-4.042-1.61-4.042-1.61C4.422 18.07 3.633 17.7 3.633 17.7c-1.087-.744.084-.729.084-.729 1.205.084 1.838 1.236 1.838 1.236 1.07 1.835 2.809 1.305 3.495.998.108-.776.417-1.305.76-1.605-2.665-.3-5.466-1.332-5.466-5.93 0-1.31.465-2.38 1.235-3.22-.135-.303-.54-1.523.105-3.176 0 0 1.005-.322 3.3 1.23.96-.267 1.98-.399 3-.405 1.02.006 2.04.138 3 .405 2.28-1.552 3.285-1.23 3.285-1.23.645 1.653.24 2.873.12 3.176.765.84 1.23 1.91 1.23 3.22 0 4.61-2.805 5.625-5.475 5.92.42.36.81 1.096.81 2.22 0 1.606-.015 2.896-.015 3.286 0 .315.21.69.825.57C20.565 22.092 24 17.592 24 12.297c0-6.627-5.373-12-12-12"/></svg></a><a class="VPSocialLink" href="https://juejin.cn/user/1887205216238477" target="_blank" rel="noopener" data-v-819d8281 data-v-ba84061a><svg width="36" height="28" viewBox="0 0 36 28" fill="none" xmlns="http://www.w3.org/2000/svg"><path fill-rule="evenodd" clip-rule="evenodd" d="M17.5875 6.77268L21.8232 3.40505L17.5875 0.00748237L17.5837 0L13.3555 3.39757L17.5837 6.76894L17.5875 6.77268ZM17.5863 17.3955H17.59L28.5161 8.77432L25.5526 6.39453L17.59 12.6808H17.5863L17.5825 12.6845L9.61993 6.40201L6.66016 8.78181L17.5825 17.3992L17.5863 17.3955ZM17.5828 23.2891L17.5865 23.2854L32.2133 11.7456L35.1768 14.1254L28.5238 19.3752L17.5865 28L0.284376 14.3574L0 14.1291L2.95977 11.7531L17.5828 23.2891Z" fill="#1E80FF"/></svg></a><!--]--></div><div class="VPFlyout VPNavBarExtra extra" data-v-fe00b0e5 data-v-0467f0ad data-v-e76b733c><button type="button" class="button" aria-haspopup="true" aria-expanded="false" aria-label="extra navigation" data-v-e76b733c><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="icon" data-v-e76b733c><circle cx="12" cy="12" r="2"></circle><circle cx="19" cy="12" r="2"></circle><circle cx="5" cy="12" r="2"></circle></svg></button><div class="menu" data-v-e76b733c><div class="VPMenu" data-v-e76b733c data-v-faf23071><!----><!--[--><!--[--><!----><div class="group" data-v-0467f0ad><div class="item appearance" data-v-0467f0ad><p class="label" data-v-0467f0ad>Appearance</p><div class="appearance-action" data-v-0467f0ad><button class="VPSwitch VPSwitchAppearance" type="button" role="switch" aria-label="toggle dark mode" aria-checked="false" data-v-0467f0ad data-v-867372a0 data-v-dc009bc3><span class="check" data-v-dc009bc3><span class="icon" data-v-dc009bc3><!--[--><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="sun" data-v-867372a0><path d="M12,18c-3.3,0-6-2.7-6-6s2.7-6,6-6s6,2.7,6,6S15.3,18,12,18zM12,8c-2.2,0-4,1.8-4,4c0,2.2,1.8,4,4,4c2.2,0,4-1.8,4-4C16,9.8,14.2,8,12,8z"></path><path d="M12,4c-0.6,0-1-0.4-1-1V1c0-0.6,0.4-1,1-1s1,0.4,1,1v2C13,3.6,12.6,4,12,4z"></path><path d="M12,24c-0.6,0-1-0.4-1-1v-2c0-0.6,0.4-1,1-1s1,0.4,1,1v2C13,23.6,12.6,24,12,24z"></path><path d="M5.6,6.6c-0.3,0-0.5-0.1-0.7-0.3L3.5,4.9c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l1.4,1.4c0.4,0.4,0.4,1,0,1.4C6.2,6.5,5.9,6.6,5.6,6.6z"></path><path d="M19.8,20.8c-0.3,0-0.5-0.1-0.7-0.3l-1.4-1.4c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l1.4,1.4c0.4,0.4,0.4,1,0,1.4C20.3,20.7,20,20.8,19.8,20.8z"></path><path d="M3,13H1c-0.6,0-1-0.4-1-1s0.4-1,1-1h2c0.6,0,1,0.4,1,1S3.6,13,3,13z"></path><path d="M23,13h-2c-0.6,0-1-0.4-1-1s0.4-1,1-1h2c0.6,0,1,0.4,1,1S23.6,13,23,13z"></path><path d="M4.2,20.8c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l1.4-1.4c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-1.4,1.4C4.7,20.7,4.5,20.8,4.2,20.8z"></path><path d="M18.4,6.6c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l1.4-1.4c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-1.4,1.4C18.9,6.5,18.6,6.6,18.4,6.6z"></path></svg><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="moon" data-v-867372a0><path d="M12.1,22c-0.3,0-0.6,0-0.9,0c-5.5-0.5-9.5-5.4-9-10.9c0.4-4.8,4.2-8.6,9-9c0.4,0,0.8,0.2,1,0.5c0.2,0.3,0.2,0.8-0.1,1.1c-2,2.7-1.4,6.4,1.3,8.4c2.1,1.6,5,1.6,7.1,0c0.3-0.2,0.7-0.3,1.1-0.1c0.3,0.2,0.5,0.6,0.5,1c-0.2,2.7-1.5,5.1-3.6,6.8C16.6,21.2,14.4,22,12.1,22zM9.3,4.4c-2.9,1-5,3.6-5.2,6.8c-0.4,4.4,2.8,8.3,7.2,8.7c2.1,0.2,4.2-0.4,5.8-1.8c1.1-0.9,1.9-2.1,2.4-3.4c-2.5,0.9-5.3,0.5-7.5-1.1C9.2,11.4,8.1,7.7,9.3,4.4z"></path></svg><!--]--></span></span></button></div></div></div><div class="group" data-v-0467f0ad><div class="item social-links" data-v-0467f0ad><div class="VPSocialLinks social-links-list" data-v-0467f0ad data-v-819d8281><!--[--><a class="VPSocialLink" href="https://github.com/ZiuChen" target="_blank" rel="noopener" data-v-819d8281 data-v-ba84061a><svg role="img" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><title>GitHub</title><path d="M12 .297c-6.63 0-12 5.373-12 12 0 5.303 3.438 9.8 8.205 11.385.6.113.82-.258.82-.577 0-.285-.01-1.04-.015-2.04-3.338.724-4.042-1.61-4.042-1.61C4.422 18.07 3.633 17.7 3.633 17.7c-1.087-.744.084-.729.084-.729 1.205.084 1.838 1.236 1.838 1.236 1.07 1.835 2.809 1.305 3.495.998.108-.776.417-1.305.76-1.605-2.665-.3-5.466-1.332-5.466-5.93 0-1.31.465-2.38 1.235-3.22-.135-.303-.54-1.523.105-3.176 0 0 1.005-.322 3.3 1.23.96-.267 1.98-.399 3-.405 1.02.006 2.04.138 3 .405 2.28-1.552 3.285-1.23 3.285-1.23.645 1.653.24 2.873.12 3.176.765.84 1.23 1.91 1.23 3.22 0 4.61-2.805 5.625-5.475 5.92.42.36.81 1.096.81 2.22 0 1.606-.015 2.896-.015 3.286 0 .315.21.69.825.57C20.565 22.092 24 17.592 24 12.297c0-6.627-5.373-12-12-12"/></svg></a><a class="VPSocialLink" href="https://juejin.cn/user/1887205216238477" target="_blank" rel="noopener" data-v-819d8281 data-v-ba84061a><svg width="36" height="28" viewBox="0 0 36 28" fill="none" xmlns="http://www.w3.org/2000/svg"><path fill-rule="evenodd" clip-rule="evenodd" d="M17.5875 6.77268L21.8232 3.40505L17.5875 0.00748237L17.5837 0L13.3555 3.39757L17.5837 6.76894L17.5875 6.77268ZM17.5863 17.3955H17.59L28.5161 8.77432L25.5526 6.39453L17.59 12.6808H17.5863L17.5825 12.6845L9.61993 6.40201L6.66016 8.78181L17.5825 17.3992L17.5863 17.3955ZM17.5828 23.2891L17.5865 23.2854L32.2133 11.7456L35.1768 14.1254L28.5238 19.3752L17.5865 28L0.284376 14.3574L0 14.1291L2.95977 11.7531L17.5828 23.2891Z" fill="#1E80FF"/></svg></a><!--]--></div></div></div><!--]--><!--]--></div></div></div><!--[--><!--]--><button type="button" class="VPNavBarHamburger hamburger" aria-label="mobile navigation" aria-expanded="false" aria-controls="VPNavScreen" data-v-fe00b0e5 data-v-f1813d69><span class="container" data-v-f1813d69><span class="top" data-v-f1813d69></span><span class="middle" data-v-f1813d69></span><span class="bottom" data-v-f1813d69></span></span></button></div></div></div></div><!----></header><div class="VPLocalNav" data-v-3af881ed data-v-07d63927><button class="menu" aria-expanded="false" aria-controls="VPSidebarNav" data-v-07d63927><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="menu-icon" data-v-07d63927><path d="M17,11H3c-0.6,0-1-0.4-1-1s0.4-1,1-1h14c0.6,0,1,0.4,1,1S17.6,11,17,11z"></path><path d="M21,7H3C2.4,7,2,6.6,2,6s0.4-1,1-1h18c0.6,0,1,0.4,1,1S21.6,7,21,7z"></path><path d="M21,15H3c-0.6,0-1-0.4-1-1s0.4-1,1-1h18c0.6,0,1,0.4,1,1S21.6,15,21,15z"></path><path d="M17,19H3c-0.6,0-1-0.4-1-1s0.4-1,1-1h14c0.6,0,1,0.4,1,1S17.6,19,17,19z"></path></svg><span class="menu-text" data-v-07d63927>Menu</span></button><a class="top-link" href="#" data-v-07d63927>Return to top</a></div><aside class="VPSidebar" data-v-3af881ed data-v-eec6a639><div class="curtain" data-v-eec6a639></div><nav class="nav" id="VPSidebarNav" aria-labelledby="sidebar-aria-label" tabindex="-1" data-v-eec6a639><span class="visually-hidden" id="sidebar-aria-label" data-v-eec6a639> Sidebar Navigation </span><!--[--><!--]--><!--[--><div class="group" data-v-eec6a639><section class="VPSidebarItem level-0 collapsible" data-v-eec6a639 data-v-66b47b62><div class="item" role="button" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link" data-v-66b47b62 data-v-8dd200cc><!--[--><h2 class="text" data-v-66b47b62>我的项目</h2><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="caret-icon" data-v-66b47b62><path d="M9,19c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l5.3-5.3L8.3,6.7c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l6,6c0.4,0.4,0.4,1,0,1.4l-6,6C9.5,18.9,9.3,19,9,19z"></path></svg></div></div><div class="items" data-v-66b47b62><!--[--><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/project/ClipboardManager/" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>超级剪贴板</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/project/Markdown/" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>超级Markdown</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/project/SmartWordBreak/" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>超级分词</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><!--]--></div></section></div><div class="group" data-v-eec6a639><section class="VPSidebarItem level-0 collapsible" data-v-eec6a639 data-v-66b47b62><div class="item" role="button" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link" data-v-66b47b62 data-v-8dd200cc><!--[--><h2 class="text" data-v-66b47b62>开源作品</h2><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="caret-icon" data-v-66b47b62><path d="M9,19c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l5.3-5.3L8.3,6.7c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l6,6c0.4,0.4,0.4,1,0,1.4l-6,6C9.5,18.9,9.3,19,9,19z"></path></svg></div></div><div class="items" data-v-66b47b62><!--[--><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/works/opensource.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>个人作品</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/works/contribution.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>社区贡献</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><!--]--></div></section></div><div class="group" data-v-eec6a639><section class="VPSidebarItem level-0 collapsible" data-v-eec6a639 data-v-66b47b62><div class="item" role="button" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link" data-v-66b47b62 data-v-8dd200cc><!--[--><h2 class="text" data-v-66b47b62>文章归档</h2><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="caret-icon" data-v-66b47b62><path d="M9,19c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l5.3-5.3L8.3,6.7c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l6,6c0.4,0.4,0.4,1,0,1.4l-6,6C9.5,18.9,9.3,19,9,19z"></path></svg></div></div><div class="items" data-v-66b47b62><!--[--><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/article/%E3%80%902023%E3%80%91%E9%9D%92%E8%AE%AD%E8%90%A5%20-%20%E5%89%8D%E7%AB%AF%E7%BB%83%E4%B9%A0%E9%A2%98%E6%B1%87%E6%80%BB%E8%A7%A3%E6%9E%90.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>【2023】青训营 - 前端练习题汇总解析</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/article/%E3%80%90%E5%AD%97%E8%8A%82%E8%B7%B3%E5%8A%A8%E3%80%91%E5%89%8D%E7%AB%AF%E9%9D%A2%E8%AF%95%E9%A2%98%E6%80%BB%E7%BB%93.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>【字节跳动】前端面试题总结</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/article/%E3%80%90%E5%BF%AB%E6%89%8B%E3%80%91%E6%B7%B1%E5%85%A5%E7%90%86%E8%A7%A3%E5%89%8D%E7%AB%AF%E9%9D%A2%E8%AF%95%E9%A2%98.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>【快手】深入理解前端面试题</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/article/%E3%80%90%E7%94%A8%E5%8F%8B%E9%87%91%E8%9E%8D%E3%80%91%E5%89%8D%E7%AB%AF%E9%9D%A2%E8%AF%95%E9%A2%98%E6%80%BB%E7%BB%93.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>【用友金融】前端面试题总结</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/article/%E4%B8%80%E6%96%87%E8%AF%BB%E6%87%82%E4%BA%8B%E4%BB%B6%E5%86%92%E6%B3%A1%E4%B8%8E%E4%BA%8B%E4%BB%B6%E6%8D%95%E8%8E%B7.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>一文读懂事件冒泡与事件捕获</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/article/%E4%B8%80%E6%96%87%E8%AF%BB%E6%87%82%E4%BC%AA%E7%B1%BB%E4%B8%8E%E4%BC%AA%E5%85%83%E7%B4%A0.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>一文读懂伪类与伪元素</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/article/%E4%B8%80%E6%96%87%E8%AF%BB%E6%87%82%E5%87%BD%E6%95%B0%E4%B8%ADthis%E6%8C%87%E5%90%91%E9%97%AE%E9%A2%98.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>一文读懂函数中this指向问题</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" 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-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>从0实现一个年度报告</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/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.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>彻底搞懂对象的数据属性描述符、存储属性描述符</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" 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-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>浅析defineProperty与Proxy实现的双向绑定</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/article/%E6%B7%B1%E5%85%A5JavaScript%E6%95%B0%E6%8D%AE%E7%B1%BB%E5%9E%8B.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>深入JavaScript数据类型</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" 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-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>深入Vue3源码，看看Vue.use后究竟发生了什么？</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></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-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>深入理解Proxy与Reflect</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></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-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>深入理解浏览器缓存机制</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></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-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>深入理解浏览器运行原理</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><!--]--></div></section></div><div class="group" data-v-eec6a639><section class="VPSidebarItem level-0 collapsible" data-v-eec6a639 data-v-66b47b62><div class="item" role="button" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link" data-v-66b47b62 data-v-8dd200cc><!--[--><h2 class="text" data-v-66b47b62>学习笔记</h2><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="caret-icon" data-v-66b47b62><path d="M9,19c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l5.3-5.3L8.3,6.7c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l6,6c0.4,0.4,0.4,1,0,1.4l-6,6C9.5,18.9,9.3,19,9,19z"></path></svg></div></div><div class="items" data-v-66b47b62><!--[--><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/note/JavaScript.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>JavaScript基础</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/note/CSS.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>CSS基础</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/note/JavaScriptEnhanced.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>JavaScript进阶</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/note/Front-end%20Engineering.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>前端工程化</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><div class="VPSidebarItem level-1 is-link" data-v-66b47b62 data-v-66b47b62><div class="item" data-v-66b47b62><div class="indicator" data-v-66b47b62></div><a class="VPLink link link" href="/note/SSR.html" data-v-66b47b62 data-v-8dd200cc><!--[--><p class="text" data-v-66b47b62>服务端渲染</p><!--]--><!----></a><div class="caret" role="button" data-v-66b47b62><!----></div></div><!----></div><!--]--></div></section></div><!--]--><!--[--><!--]--></nav></aside><div class="VPContent has-sidebar" id="VPContent" data-v-3af881ed data-v-e31feb0e><div class="VPDoc has-sidebar has-aside" data-v-e31feb0e data-v-30dabfe4><div class="container" data-v-30dabfe4><div class="aside" data-v-30dabfe4><div class="aside-curtain" data-v-30dabfe4></div><div class="aside-container" data-v-30dabfe4><div class="aside-content" data-v-30dabfe4><div class="VPDocAside" data-v-30dabfe4 data-v-7110f5c9><!--[--><!--]--><!--[--><!--]--><div class="VPDocAsideOutline" data-v-7110f5c9 data-v-9c6f1a55><div class="content" data-v-9c6f1a55><div class="outline-marker" data-v-9c6f1a55></div><div class="outline-title" data-v-9c6f1a55>On this page</div><nav aria-labelledby="doc-outline-aria-label" data-v-9c6f1a55><span class="visually-hidden" id="doc-outline-aria-label" data-v-9c6f1a55> Table of Contents for current page </span><ul class="root" data-v-9c6f1a55 data-v-02afc12d><!--[--><!--]--></ul></nav></div></div><!--[--><!--]--><div class="spacer" data-v-7110f5c9></div><!--[--><!--]--><!----><!--[--><!--]--><!--[--><!--]--></div></div></div></div><div class="content" data-v-30dabfe4><div class="content-container" data-v-30dabfe4><!--[--><!--]--><main class="main" data-v-30dabfe4><div style="position:relative;" class="vp-doc _note_React" data-v-30dabfe4><div><h1 id="react" tabindex="-1">React <a class="header-anchor" href="#react" aria-hidden="true">#</a></h1><h2 id="邂逅react" tabindex="-1">邂逅React <a class="header-anchor" href="#邂逅react" aria-hidden="true">#</a></h2><h3 id="react开发依赖" tabindex="-1">React开发依赖 <a class="header-anchor" href="#react开发依赖" aria-hidden="true">#</a></h3><ul><li><code>react</code> 包含React的核心代码</li><li><code>react-dom</code> 将React渲染到不同平台需要的核心代码</li><li><code>babel</code> 将JSX转换成React代码的工具</li></ul><p>为什么要拆分成这么多的包？</p><ul><li>不同的库各司其职，让库变得纯粹</li><li><code>react</code>包中包含了 React Web 和 React Native 共同拥有的<strong>核心代码</strong></li><li><code>react-dom</code> 针对Web和Native完成的事情不同 <ul><li>Web端：<code>react-dom</code>会将JSX渲染成真实DOM，展示在浏览器中</li><li>Native端：<code>react-dom</code>会将JSX渲染成原生的控件（如Android中的Button，iOS中的UIButton）</li></ul></li></ul><h3 id="babel与react的关系" tabindex="-1">Babel与React的关系 <a class="header-anchor" href="#babel与react的关系" aria-hidden="true">#</a></h3><p>Babel是什么？</p><ul><li>Babel又名Babel.js</li><li>是目前前端使用非常广泛的编译器、转换器（Compiler/Transformer）</li><li>提供对ES6语法的Polyfill，将ES6语法转为大多数浏览器都支持的ES5语法</li></ul><p>二者之间的联系</p><ul><li>默认情况下React开发可以不使用Babel</li><li>但是我们不可能使用React.createElement来编写代码</li><li>通过Babel，我们可以直接编写JSX（JavaScript XML），让Babel帮我们转化为React.createElement</li></ul><h3 id="react初体验" tabindex="-1">React初体验 <a class="header-anchor" href="#react初体验" aria-hidden="true">#</a></h3><p>我们通过CDN方式引入react、react-dom、babel这三个依赖</p><p>并且创建<code>#root</code>根节点，作为渲染React组件的容器，再新建一个script标签，键入以下内容</p><div class="language-html line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">html</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">id</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">root</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">script</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">src</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">https://unpkg.com/react@18/umd/react.development.js</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">crossorigin</span><span style="color:#89DDFF;">&gt;&lt;/</span><span style="color:#F07178;">script</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">script</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">src</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">https://unpkg.com/react-dom@18/umd/react-dom.development.js</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">crossorigin</span><span style="color:#89DDFF;">&gt;&lt;/</span><span style="color:#F07178;">script</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">script</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">src</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">https://unpkg.com/babel-standalone@6/babel.min.js</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">crossorigin</span><span style="color:#89DDFF;">&gt;&lt;/</span><span style="color:#F07178;">script</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">script</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">type</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">text/babel</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Hello, React!</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;,</span><span style="color:#A6ACCD;"> document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">script</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"></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></div></div><p>这时，一个内容为<code>Hello, React!</code>的div标签就被渲染到页面上了</p><p>需要注意的是：<code>ReactDOM.render</code>这种写法适用于React18之前，在React18之后建议用下面的代码渲染根节点：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Hello, React!</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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></div></div><h3 id="第一个react程序" tabindex="-1">第一个React程序 <a class="header-anchor" href="#第一个react程序" aria-hidden="true">#</a></h3><p>设想我们现在有这样一个需求：点击按钮使文本<code>Hello, World!</code>变为<code>Hello, React!</code></p><p>我们很容易就能写出如下代码：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#C792EA;">let</span><span style="color:#A6ACCD;"> msg </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, World!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">() </span><span style="color:#676E95;font-style:italic;">// initial render</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">function</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">handleChangeClick</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">msg</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, React!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">msg</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={</span><span style="color:#A6ACCD;">handleChangeClick</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Text</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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></div></div><p>在Vue中，如果我们对数据进行了修改，Vue的数据响应式会自动帮我们完成视图的更新</p><p>然而在React中，当我们修改了数据需要通知React，让React重新渲染视图。在这里，我们可以把渲染的过程封装为一个函数，方便我们重复调用，触发重新渲染</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#C792EA;">let</span><span style="color:#A6ACCD;"> msg </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, World!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">() </span><span style="color:#676E95;font-style:italic;">// initial render</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">function</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">handleChangeClick</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">msg</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, React!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#82AAFF;">render</span><span style="color:#F07178;">() </span><span style="color:#676E95;font-style:italic;">// re-render</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">function</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#F07178;">(</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">msg</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={</span><span style="color:#A6ACCD;">handleChangeClick</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Text</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></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><p>这个案例中，我们使用<code>{}</code>语法，将动态的JS语法嵌入到JSX代码中</p><h3 id="组件化开发" tabindex="-1">组件化开发 <a class="header-anchor" href="#组件化开发" aria-hidden="true">#</a></h3><p>React有两种组件：类组件与函数组件，React18+推荐使用函数组件+Hooks</p><h4 id="类组件" tabindex="-1">类组件 <a class="header-anchor" href="#类组件" aria-hidden="true">#</a></h4><p>我们使用类组件来逐步重构上面的案例：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> msg</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, World!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h2</span><span style="color:#89DDFF;">&gt;{this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">msg</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">h2</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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></div></div><ul><li><p>类组件必须实现render方法，render方法返回值为后续React渲染到页面的内容</p></li><li><p>组件内数据分为两类</p><ul><li>参与页面更新的数据 <ul><li>当数据变化时，需要触发组件重新渲染</li></ul></li><li>不参与页面更新的数据 <ul><li>数据不会变化，或变化后也不需要重新渲染视图</li></ul></li></ul></li><li><p>需要触发视图重新渲染的数据，我们将其成为：<strong>参与数据流</strong></p><ul><li>定义在对象的<code>state</code>属性中</li><li>可以通过在构造函数中通过 <code>this.state = { name: &#39;Ziu&#39; }</code> 来定义状态</li><li>当数据发生变化，可以调用 <code>this.setState</code> 来更新数据，通知React执行视图更新</li><li>update操作时，会重新调用render函数，使用最新的数据来渲染界面</li></ul></li></ul><p>:::success 需要注意的是，在constructor中我们调用了<code>super</code>，因为App类是继承自React.Component类，调用<code>super</code>即调用了其父类的构造函数，让我们的App组件可以继承一些内置属性/方法如<code>state setState render</code> :::</p><p>至此我们完成了数据的迁移，下面我们来完成事件函数的迁移。</p><p>有了之前的介绍，我们很容易的可以写出下面的代码：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> msg</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, World!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">changeText</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> msg</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, React!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h2</span><span style="color:#89DDFF;">&gt;{this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">msg</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">h2</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">changeText</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Text</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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><p>我们可以写一个实例方法changeText来修改msg，然而，此时我们点击按钮后发现，案例不能正常工作。</p><p>如果在changeText中打log，会发现函数被正常触发了，但是状态没有更新</p><p>为什么this.setState失效了？这和this的绑定有关：绑定的<code>changeText</code>在被调用时，向上找<code>this</code>找到的是全局的<code>this</code>即<code>undefined</code></p><p>这种情况有点类似于下面的例子：</p><div class="language-ts line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">ts</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> app </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">new</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">App</span><span style="color:#A6ACCD;">()</span></span>
<span class="line"><span style="color:#A6ACCD;">app</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">changeText</span><span style="color:#A6ACCD;">() </span><span style="color:#676E95;font-style:italic;">// this =&gt; app</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> func </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> app</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">changeText</span></span>
<span class="line"><span style="color:#82AAFF;">func</span><span style="color:#A6ACCD;">() </span><span style="color:#676E95;font-style:italic;">// this =&gt; undefined</span></span>
<span class="line"></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></div></div><p>在非严格模式下，直接调用func时的this指向的是window，严格模式下则为undefined</p><p>为了解决this绑定的问题，我们需要显式把函数调用绑定给当前组件，这时组件就可以正常工作了。</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight has-highlighted-lines"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> msg</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, World!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">changeText</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> msg</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, React!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h2</span><span style="color:#89DDFF;">&gt;{this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">msg</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">h2</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line highlighted"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">changeText</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">bind</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">this</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Text</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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="提前绑定this" tabindex="-1">提前绑定this <a class="header-anchor" href="#提前绑定this" aria-hidden="true">#</a></h3><p>在render函数中频繁通过<code>.bind</code>毕竟不太优雅，好在也有另一种方式：可以在constructor中提前对实例方法进行this绑定：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight has-highlighted-lines"><code><span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"><span style="color:#82AAFF;">constructor</span><span style="color:#A6ACCD;">() </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> msg</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, World!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line highlighted"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">changeText</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">changeText</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">bind</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">this</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">() </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">...</span></span>
<span class="line highlighted"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">changeText</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Text</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">...</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"></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></div></div><h3 id="列表渲染" tabindex="-1">列表渲染 <a class="header-anchor" href="#列表渲染" aria-hidden="true">#</a></h3><p>可以通过循环，将数组渲染到视图中</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> movieList</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> [</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">The Shawshank Redemption</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">The Godfather</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">The Godfather: Part II</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">The Dark Knight</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#F07178;"> ]</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">ul</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">movieList</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">map</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">item</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> (</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">key</span><span style="color:#89DDFF;">={</span><span style="color:#A6ACCD;">item</span><span style="color:#89DDFF;">}&gt;{</span><span style="color:#A6ACCD;">item</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> ))</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">ul</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br></div></div><p>需要注意的是，这里绑定的key的功能类似于Vue中的特殊属性key，它用来帮助React对列表渲染进行更高效的更新。</p><h3 id="计数器案例" tabindex="-1">计数器案例 <a class="header-anchor" href="#计数器案例" aria-hidden="true">#</a></h3><p>结合之前的知识，可以实现一个简单的计数器</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> count</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">0</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">addCount</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">addCount</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">bind</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">this</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">subCount</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">subCount</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">bind</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">this</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">addCount</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> count</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">count</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">+</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">1</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">subCount</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> count</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">count</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">-</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">1</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">count</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Count: </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">count</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">addCount</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Add</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">subCount</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Sub</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br></div></div><h2 id="认识jsx语法" tabindex="-1">认识JSX语法 <a class="header-anchor" href="#认识jsx语法" aria-hidden="true">#</a></h2><ul><li>认识JSX语法</li><li>JSX基本使用</li><li>JSX事件绑定</li><li>JSX条件渲染</li><li>JSX列表渲染</li><li>JSX的原理与本质</li></ul><p>是因为我们给script标签添加了<code>type=&quot;text/babel&quot;</code>属性，浏览器不会对这个script进行解析，当babel被加载完成后，babel会在页面中寻找<code>type=&quot;text/babel&quot;</code>的script标签进行转义，转义后的代码才会被浏览器执行</p><ul><li>JSX: JavaScript Extension / JavaScript XML</li><li>All in JS</li><li>不同于Vue的模板语法 不需要专门学习模板语法中的指令(v-for/v-if/v-bind)</li></ul><h3 id="jsx的使用" tabindex="-1">JSX的使用 <a class="header-anchor" href="#jsx的使用" aria-hidden="true">#</a></h3><h4 id="书写jsx的规范与注意事项" tabindex="-1">书写JSX的规范与注意事项 <a class="header-anchor" href="#书写jsx的规范与注意事项" aria-hidden="true">#</a></h4><ul><li>JSX的顶层只能有一个根元素 元素必须包裹在单独的闭合标签中 <ul><li>后续会接触到Fragment标签 Vue3也是将元素包裹在了Fragments标签中</li></ul></li><li>为了方便阅读 通常在JSX外层包裹一个小括号<code>()</code>方便阅读</li></ul><h4 id="jsx的注释" tabindex="-1">JSX的注释 <a class="header-anchor" href="#jsx的注释" aria-hidden="true">#</a></h4><p>在JSX中编写注释，需要以<code>{/* ... */}</code>的形式，在<code>.jsx/.tsx</code>文件中，通过快捷键就可以快捷的生成注释内容</p><p>本质上是通过花括号语法<code>{}</code>嵌入了一段JavaScript表达式，在表达式中书写注释</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight has-highlighted-lines"><code><span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#A6ACCD;"> (</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line highlighted"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#676E95;font-style:italic;">/* Some Comment... */</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Count: </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">count</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">addCount</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Add</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">subCount</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Sub</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;">)</span></span>
<span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"></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></div></div><h4 id="jsx嵌入变量作为子元素" tabindex="-1">JSX嵌入变量作为子元素 <a class="header-anchor" href="#jsx嵌入变量作为子元素" aria-hidden="true">#</a></h4><p>可以通过花括号语法将变量内容嵌入到JSX语法中：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> message </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hello, React!</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> arr </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> [</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">abc</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">cba</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">nba</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">]</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#A6ACCD;"> (</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;"> message </span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;"> arr </span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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></div></div><ul><li>变量类型为number string array类型时，可以直接展示</li><li>变量类型为null undefined boolean类型时，内容为空 <ul><li>如果希望可以展示null/undefined/boolean类型，需要通过<code>.toString()</code>方法将其转为字符串</li><li>空字符串拼接、String构造函数等方式</li></ul></li><li>Object对象类型不能作为子元素 (Objects are not valid as a React child)</li></ul><p>下例中，只有number类型会被正常展示，而其余变量则不会展示在视图中</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">() </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">number</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">123</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">n</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">null</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">u</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">undefined</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">b</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#FF9CAC;">true</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> Number: </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">number</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> Null: </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">n</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> Undefined: </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">u</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> Boolean: </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">b</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></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></div></div><p>将对象类型变量嵌入到JSX语法中，React会抛出错误：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight has-highlighted-lines"><code><span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">() </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">obj</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> name</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Ziu</span><span style="color:#89DDFF;">&#39;</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line highlighted"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;"> obj </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"></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></div></div><h4 id="jsx的属性绑定" tabindex="-1">JSX的属性绑定 <a class="header-anchor" href="#jsx的属性绑定" aria-hidden="true">#</a></h4><ul><li>在Vue中我们通过<code>v-bind</code>绑定属性</li><li>在React中如何绑定元素属性？</li><li><code>title</code> <code>src</code> <code>href</code> <code>class</code> 内联<code>style</code>等</li></ul><p>下例中，我们通过花括号语法对元素的属性进行了动态绑定，点击按钮可以切换className状态</p><p>同时，动态绑定的内联样式也会发生改变，通过花括号语法动态绑定style属性</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> isActive</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#FF9CAC;">false</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#F07178;"> title</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Description</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">changeActive</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">changeActive</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">bind</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">this</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">changeActive</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> isActive</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">!this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">isActive</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">isActive</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">title</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">classList</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> [</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">title</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">isActive</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">?</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">active</span><span style="color:#89DDFF;">&#39;</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;&#39;</span><span style="color:#F07178;">]</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span></span>
<span class="line"><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">={</span><span style="color:#A6ACCD;">classList</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">join</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">title</span><span style="color:#89DDFF;">={</span><span style="color:#A6ACCD;">title</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">style</span><span style="color:#89DDFF;">={{</span><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">color</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> isActive </span><span style="color:#89DDFF;">?</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">red</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">blue</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}}</span></span>
<span class="line"><span style="color:#89DDFF;"> &gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> Hello, React!</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">changeActive</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Active</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br></div></div><p>当我们通过脚手架创建项目时，可以使用第三方库来帮我们完成className的绑定</p><ul><li><code>classnames</code>库 <code>pnpm add classnames</code></li><li>提供了多种创建className的语法</li></ul><h3 id="jsx事件绑定" tabindex="-1">JSX事件绑定 <a class="header-anchor" href="#jsx事件绑定" aria-hidden="true">#</a></h3><p>先前的例子中，我们已经通过<code>onClick</code>给按钮绑定过事件处理函数了，其中涉及了this绑定</p><p>回顾一下this的四种绑定规则：</p><ol><li>默认绑定 独立执行 foo() this =&gt; undefined</li><li>隐式绑定 被一个对象执行 obj.foo() this =&gt; obj</li><li>显式绑定 call/bind/apply foo.call(&#39;aaa&#39;) this =&gt; String(&#39;aaa&#39;)</li><li>new绑定 new Foo() 创建一个新对象，并且赋值给this</li></ol><p>除了之前通过<code>function + bind</code>绑定事件处理函数的方式，还可以通过箭头函数来帮我们完成处理</p><p>箭头函数的内部使用this时会自动向上层作用域查找this 实际开发中这种方式并不常用</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight has-highlighted-lines"><code><span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line highlighted"><span style="color:#82AAFF;">changeActive</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> isActive</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">!this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">isActive</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"></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></div></div><p>相比之下更推荐使用的，是下面这种方式：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight has-highlighted-lines"><code><span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line highlighted"><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={()</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">changeActive</span><span style="color:#A6ACCD;">()</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Active</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"></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></div></div><p>这样书写有几种好处：</p><ul><li>给事件处理函数传递参数更方便</li><li>书写更方便 不必主动考虑this绑定问题</li></ul><p>它的原理是，我们对外暴露的本质上是一个箭头函数，当调用箭头函数时，本质上是执行<code>this.changeActive</code>，这是 一种隐式绑定，找到的this为当前组件实例</p><h3 id="事件绑定参数传递" tabindex="-1">事件绑定参数传递 <a class="header-anchor" href="#事件绑定参数传递" aria-hidden="true">#</a></h3><ul><li>Event参数传递</li><li>额外参数传递</li></ul><p>事件回调函数的第一个默认参数就是Event对象，这个Event对象是经过React包装后的，但是原生的属性都包含在内，React对其进行了一些扩展</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight has-highlighted-lines"><code><span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"><span style="color:#82AAFF;">changeActive</span><span style="color:#A6ACCD;">(ev) </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">console</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">log</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Event</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">ev</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">() </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#676E95;font-style:italic;">/* event将作为默认入参传递给changeActive */</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">changeActive</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Active</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#676E95;font-style:italic;">/* 通过箭头函数绑定事件监听回调函数时 需要手动透传一下event */</span><span style="color:#89DDFF;">}</span></span>
<span class="line highlighted"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={(</span><span style="color:#A6ACCD;font-style:italic;">ev</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">changeActive</span><span style="color:#A6ACCD;">(ev)</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Active</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">...</span></span>
<span class="line"></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></div></div><p>当我们需要传递额外的参数时，通过箭头函数传递也更容易：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight has-highlighted-lines"><code><span class="line"><span style="color:#82AAFF;">changeActive</span><span style="color:#A6ACCD;">(ev</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> name</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> age) </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">console</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">log</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Event</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">ev</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">console</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">log</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Name</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">name</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">console</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">log</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Age</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">age</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">() </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#676E95;font-style:italic;">/* NOT Recommand */</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={this.</span><span style="color:#A6ACCD;">changeActive</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">bind</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">this,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Ziu</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">18</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Active</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#676E95;font-style:italic;">/* Recommand */</span><span style="color:#89DDFF;">}</span></span>
<span class="line highlighted"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={(</span><span style="color:#A6ACCD;font-style:italic;">ev</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">changeActive</span><span style="color:#A6ACCD;">(ev</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Ziu</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">18</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Change Active</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></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></div></div><p>需要注意，当通过<code>.bind</code>传递额外参数时，最后一个参数才是默认传递的Event对象，这会导致非预期行为</p><div class="language-sh line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">sh</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;"> Event </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Ziu</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;"> Name </span><span style="color:#F78C6C;">18</span></span>
<span class="line"><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;"> Age </span><span style="color:#89DDFF;">{</span><span style="color:#FFCB6B;">Event</span><span style="color:#89DDFF;">}</span></span>
<span class="line"></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></div></div><h3 id="jsx事件绑定案例" tabindex="-1">JSX事件绑定案例 <a class="header-anchor" href="#jsx事件绑定案例" aria-hidden="true">#</a></h3><p>创建一个Tab栏，选中哪个选项，哪个选项被激活切换为红色，同一时间仅有一个激活项目</p><p>结合之前学习的内容，很容易就可以写出下述 代码：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> activeIndex</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#F07178;"> tabList</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> [</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Home</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Recommend</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Hot</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">User</span><span style="color:#89DDFF;">&#39;</span><span style="color:#F07178;">]</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">changeActive</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">index</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> activeIndex</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">index</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">activeIndex</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">tabList</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">tabs</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">tabList</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">map</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">item</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">index</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> (</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span></span>
<span class="line"><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">={</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">tab </span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> index </span><span style="color:#89DDFF;">===</span><span style="color:#A6ACCD;"> activeIndex </span><span style="color:#89DDFF;">?</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">active</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;&#39;</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">style</span><span style="color:#89DDFF;">={{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">color</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> index </span><span style="color:#89DDFF;">===</span><span style="color:#A6ACCD;"> activeIndex </span><span style="color:#89DDFF;">?</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">red</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">black</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}}</span></span>
<span class="line"><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">key</span><span style="color:#89DDFF;">={</span><span style="color:#A6ACCD;">index</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={()</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">changeActive</span><span style="color:#A6ACCD;">(index)</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;"> &gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">item</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> ))</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br></div></div><h3 id="条件渲染" tabindex="-1">条件渲染 <a class="header-anchor" href="#条件渲染" aria-hidden="true">#</a></h3><p>控制元素按照某种条件渲染，以加载状态为例</p><p>列表未加载出来时，展示<code>加载中</code>，加载完毕则渲染完整内容：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> isLoading</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#FF9CAC;">true</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">changeLoading</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> isLoading</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">!this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">isLoading</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">isLoading</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">isLoading </span><span style="color:#89DDFF;">?</span><span style="color:#A6ACCD;"> (</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">loading</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;"> Loading ... </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> ) </span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> (</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">list</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Some Content</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> )</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={()</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">changeLoading</span><span style="color:#A6ACCD;">()</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Toggle Loading</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br></div></div><p>常用的条件渲染方式</p><ul><li><code>if/else/else-if</code><ul><li>适合判断逻辑较复杂的情况 将条件渲染抽离出来</li></ul></li><li>三元运算符 <code>?:</code><ul><li>适合判断逻辑简单的情况</li></ul></li><li>逻辑与运算符 <code>&amp;&amp;</code><ul><li>如果条件成立则渲染某个组件，否则什么内容都不渲染</li></ul></li><li>可选链 <code>user?.info?.name</code></li></ul><p>下例中通过逻辑与运算符<code>&amp;&amp;</code>决定<code>VIP</code>标签是否展示在视图中</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> isVip</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#FF9CAC;">false</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">changeVip</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> isVip</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">!this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">isVip</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">isVip</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">class</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">user</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">username: Ziu</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">isVip </span><span style="color:#89DDFF;">&amp;&amp;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">vip-banner</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;"> VIP </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={()</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">changeVip</span><span style="color:#A6ACCD;">()</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Toggle Vip</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br></div></div><h4 id="在react中简单写一个-v-show" tabindex="-1">在React中简单写一个&quot;v-show&quot; <a class="header-anchor" href="#在react中简单写一个-v-show" aria-hidden="true">#</a></h4><p><code>v-show</code>是Vue提供的语法糖，不同于<code>v-if</code>，它只切换元素的<code>display</code>属性。</p><p>下面我们在React中简单复现一个<code>v-show</code>的效果：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> isShow</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#FF9CAC;">true</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">changeShow</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> isShow</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">!this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">isShow</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">isShow</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">style</span><span style="color:#89DDFF;">={{</span><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">display</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> isShow </span><span style="color:#89DDFF;">?</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;&#39;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">none</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}}&gt;</span><span style="color:#A6ACCD;">Target Element</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={()</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">changeShow</span><span style="color:#A6ACCD;">()</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Toggle Show</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></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><span class="line-number">25</span><br></div></div><p>实际使用中，将其封装为hooks来调用更具通用性，也更方便管理</p><h3 id="列表渲染中的高阶函数" tabindex="-1">列表渲染中的高阶函数 <a class="header-anchor" href="#列表渲染中的高阶函数" aria-hidden="true">#</a></h3><ul><li><code>filter</code>函数 过滤器</li><li><code>slice</code>函数 分页</li><li><code>sorc</code>函数 排序</li><li>...</li></ul><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> stuList</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> [</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> name</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Ziu</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> age</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">18</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> score</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">88</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">},</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> name</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Kobe</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> age</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">19</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> score</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">59</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">},</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> name</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">Why</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> age</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">20</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> score</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">61</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">},</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> name</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">James</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> age</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">21</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> score</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">99</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> ]</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">stuList</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;"> </span><span style="color:#676E95;font-style:italic;">// 及格的学生</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">passStuList</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">stuList</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">filter</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">item</span><span style="color:#89DDFF;">)</span><span style="color:#F07178;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">item</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">score</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&gt;=</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">60</span><span style="color:#F07178;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;"> </span><span style="color:#676E95;font-style:italic;">// 分数最高的两个学生</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">top2StuList</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">stuList</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">sort</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">a</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;font-style:italic;">b</span><span style="color:#89DDFF;">)</span><span style="color:#F07178;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">b</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">score</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">-</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">a</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">score</span><span style="color:#F07178;">)</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">slice</span><span style="color:#F07178;">(</span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">2</span><span style="color:#F07178;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">list</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">stuList</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">map</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">({</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">name</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">age</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">score</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">})</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> (</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">item</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">key</span><span style="color:#89DDFF;">={</span><span style="color:#A6ACCD;">name</span><span style="color:#89DDFF;">}&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">name</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">name</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">age</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">age</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">score</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">score</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> ))</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br></div></div><h3 id="jsx的本质" tabindex="-1">JSX的本质 <a class="header-anchor" href="#jsx的本质" aria-hidden="true">#</a></h3><h4 id="jsx的转换过程" tabindex="-1">JSX的转换过程 <a class="header-anchor" href="#jsx的转换过程" aria-hidden="true">#</a></h4><p>假设我们有下面的JSX代码：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">page</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">page</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">header</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Header</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">content</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> Content</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">banner</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Banner</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">ul</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Item 1</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Item 2</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Item 3</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Item 4</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Item 5</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">li</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">ul</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">footer</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Footer</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">console</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">log</span><span style="color:#F07178;">(</span><span style="color:#A6ACCD;">page</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">page</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br></div></div><p>通过JSX语法描述出来的template会经过Babel转化，转化为JavaScript树的数据结构</p><p>在控制台中我们可以看到，子节点都存放进了父节点的<code>props.children</code>中</p><h4 id="虚拟dom树" tabindex="-1">虚拟DOM树 <a class="header-anchor" href="#虚拟dom树" aria-hidden="true">#</a></h4><p>JSX仅仅是<code>React.createElement(component, props, ...children)</code>的语法糖</p><p>所有的JSX语法都会被Babel转化为这样的命令式语法</p><p>.createElement函数的参数</p><ul><li>type <ul><li>当前ReactElement的类型</li><li>如果是标签元素，值为字符串如：<code>&quot;div&quot;</code></li><li>如果是组件元素，那么值为组件的名称</li></ul></li><li>config <ul><li>所有JSX中绑定的属性都在config中以键值对的形式存储</li><li>例如<code>className</code> =&gt; <code>class</code></li></ul></li></ul><p>我们借助Babel官网的Playground来检查一下JSX语法的转化</p><div class="language-js line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">js</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#89DDFF;font-style:italic;">import</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">jsx</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">as</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">_jsx</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;font-style:italic;">from</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">react/jsx-runtime</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">;</span></span>
<span class="line"><span style="color:#89DDFF;font-style:italic;">import</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">jsxs</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">as</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">_jsxs</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;font-style:italic;">from</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">react/jsx-runtime</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">;</span></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> page </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsxs</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">div</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">className</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">page</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> [</span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsx</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">div</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">className</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">header</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Header</span><span style="color:#89DDFF;">&quot;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsxs</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">div</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">className</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">content</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> [</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Content</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsx</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">div</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">className</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">banner</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Banner</span><span style="color:#89DDFF;">&quot;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsxs</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">ul</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> [</span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsx</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">li</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Item 1</span><span style="color:#89DDFF;">&quot;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsx</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">li</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Item 2</span><span style="color:#89DDFF;">&quot;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsx</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">li</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Item 3</span><span style="color:#89DDFF;">&quot;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsx</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">li</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Item 4</span><span style="color:#89DDFF;">&quot;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsx</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">li</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Item 5</span><span style="color:#89DDFF;">&quot;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)]</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)]</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;">/*#__PURE__*/</span><span style="color:#82AAFF;">_jsx</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">div</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">className</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">footer</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">children</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Footer</span><span style="color:#89DDFF;">&quot;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)]</span></span>
<span class="line"><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">;</span></span>
<span class="line"><span style="color:#A6ACCD;">console</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">log</span><span style="color:#A6ACCD;">(page)</span><span style="color:#89DDFF;">;</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br></div></div><p>这时经过Babel转义后的纯JS函数，这段函数可以在浏览器中直接运行</p><p>如果移除了相关JSX代码，并将他们都替换为<code>React.createElement</code>函数调用，那么得到的代码也可以直接在浏览器中运行。Babel帮助我们完成了转化，提高了开发效率，相比于通过调用<code>React.createElement</code>来描述视图，通过JSX编写的代码更加容易维护</p><p>这些代码最终形成的就是虚拟DOM树，React可以将虚拟DOM渲染到页面上，形成真实DOM</p><p>虚拟DOM允许React可以通过diff算法，高效地对真实DOM树进行更新</p><h3 id="声明式编程" tabindex="-1">声明式编程 <a class="header-anchor" href="#声明式编程" aria-hidden="true">#</a></h3><ul><li>虚拟DOM帮我们从命令式编程转到了声明式编程的模式</li><li>对虚拟DOM作何处理，如何渲染是由React决定的，由于做了一层抽象，那么同样可以将虚拟DOM渲染成原生组件（React Native）</li></ul><h3 id="购物车案例" tabindex="-1">购物车案例 <a class="header-anchor" href="#购物车案例" aria-hidden="true">#</a></h3><p>下面写一个经典的购物车案例</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#C792EA;">function</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">formatPrice</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">price</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">`</span><span style="color:#C3E88D;">$ </span><span style="color:#89DDFF;">${</span><span style="color:#A6ACCD;">price</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">toFixed</span><span style="color:#A6ACCD;">(</span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">}`</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">React</span><span style="color:#89DDFF;">.</span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">constructor</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> books</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> [</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> name</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">book1</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> author</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">author1</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> price</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">100</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> count</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">0</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">},</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> name</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">book2</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> author</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">author2</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> price</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">200</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> count</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">0</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">},</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> name</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">book3</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> author</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">author3</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> price</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">300</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> count</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">0</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">},</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> name</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">book4</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> author</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">author4</span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> price</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">400</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> count</span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">0</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> ]</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">changeCount</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">index</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">count</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">state</span><span style="color:#89DDFF;">)</span><span style="color:#F07178;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">books</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> [</span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">books</span><span style="color:#F07178;">]</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">books</span><span style="color:#F07178;">[</span><span style="color:#A6ACCD;">index</span><span style="color:#F07178;">]</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">count</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">+=</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">count</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">books</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">removeItem</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">index</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">setState</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">state</span><span style="color:#89DDFF;">)</span><span style="color:#F07178;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">books</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> [</span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">books</span><span style="color:#F07178;">]</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">books</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">splice</span><span style="color:#F07178;">(</span><span style="color:#A6ACCD;">index</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">1</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">books</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">getTotal</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">books</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">books</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">reduce</span><span style="color:#F07178;">(</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;font-style:italic;">acc</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;font-style:italic;">price</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;font-style:italic;">count</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">})</span><span style="color:#F07178;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">acc</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">+</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">price</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">*</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">count</span><span style="color:#89DDFF;">,</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">0</span><span style="color:#F07178;">)</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">renderBookCart</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">books</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">total</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">getTotal</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> (</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">shopping-cart</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Shopping Cart</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">h1</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">books</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;">books</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">map</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">({</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">name</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">author</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">price</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">count</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">},</span><span style="color:#A6ACCD;"> </span><span style="color:#A6ACCD;font-style:italic;">index</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> (</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">book</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">key</span><span style="color:#89DDFF;">={</span><span style="color:#A6ACCD;">name</span><span style="color:#89DDFF;">}&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">idx</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">index </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">name</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">name</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">author</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">author</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">price</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#82AAFF;">formatPrice</span><span style="color:#A6ACCD;">(price)</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">counter</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={()</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">changeCount</span><span style="color:#A6ACCD;">(index</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">-</span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">} </span><span style="color:#C792EA;">disabled</span><span style="color:#89DDFF;">={</span><span style="color:#A6ACCD;">count </span><span style="color:#89DDFF;">&lt;=</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">}&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> -</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">counter-number</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;{</span><span style="color:#A6ACCD;">count</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={()</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">changeCount</span><span style="color:#A6ACCD;">(index</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;">)</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">+</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">onClick</span><span style="color:#89DDFF;">={()</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">=&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">removeItem</span><span style="color:#A6ACCD;">(index)</span><span style="color:#89DDFF;">}&gt;</span><span style="color:#A6ACCD;">Delete</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">button</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> ))</span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">total</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Total: </span><span style="color:#89DDFF;">{</span><span style="color:#82AAFF;">formatPrice</span><span style="color:#A6ACCD;">(total)</span><span style="color:#89DDFF;">}&lt;/</span><span style="color:#F07178;">span</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> )</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">renderEmptyTip</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;"> </span><span style="color:#C792EA;">className</span><span style="color:#89DDFF;">=</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">empty</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Shopping Cart is Empty</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#C792EA;">const</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">isEmpty</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">=</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#A6ACCD;">state</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">books</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">length</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">===</span><span style="color:#F07178;"> </span><span style="color:#F78C6C;">0</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">!</span><span style="color:#A6ACCD;">isEmpty</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">?</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">renderBookCart</span><span style="color:#F07178;">() </span><span style="color:#89DDFF;">:</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">this.</span><span style="color:#82AAFF;">renderEmptyTip</span><span style="color:#F07178;">()</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></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><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br><span class="line-number">42</span><br><span class="line-number">43</span><br><span class="line-number">44</span><br><span class="line-number">45</span><br><span class="line-number">46</span><br><span class="line-number">47</span><br><span class="line-number">48</span><br><span class="line-number">49</span><br><span class="line-number">50</span><br><span class="line-number">51</span><br><span class="line-number">52</span><br><span class="line-number">53</span><br><span class="line-number">54</span><br><span class="line-number">55</span><br><span class="line-number">56</span><br><span class="line-number">57</span><br><span class="line-number">58</span><br><span class="line-number">59</span><br><span class="line-number">60</span><br><span class="line-number">61</span><br><span class="line-number">62</span><br><span class="line-number">63</span><br><span class="line-number">64</span><br><span class="line-number">65</span><br><span class="line-number">66</span><br><span class="line-number">67</span><br><span class="line-number">68</span><br><span class="line-number">69</span><br><span class="line-number">70</span><br><span class="line-number">71</span><br><span class="line-number">72</span><br><span class="line-number">73</span><br><span class="line-number">74</span><br><span class="line-number">75</span><br><span class="line-number">76</span><br><span class="line-number">77</span><br><span class="line-number">78</span><br><span class="line-number">79</span><br><span class="line-number">80</span><br><span class="line-number">81</span><br><span class="line-number">82</span><br></div></div><h2 id="react项目开发" tabindex="-1">React项目开发 <a class="header-anchor" href="#react项目开发" aria-hidden="true">#</a></h2><ul><li>认识脚手架工具</li><li>create-react-app</li><li>创建React项目</li><li>Webpack的配置</li></ul><h3 id="react脚手架" tabindex="-1">React脚手架 <a class="header-anchor" href="#react脚手架" aria-hidden="true">#</a></h3><p>类似于Vue提供的 <code>pnpm create vite</code> 创建一个模板，React也可以通过 <code>create-react-app</code> 来初始化一个空的React模板</p><div class="language-sh line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">sh</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#FFCB6B;">pnpm</span><span style="color:#A6ACCD;"> </span><span style="color:#C3E88D;">add</span><span style="color:#A6ACCD;"> </span><span style="color:#C3E88D;">create-react-app</span><span style="color:#A6ACCD;"> </span><span style="color:#C3E88D;">-g</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;"># 全局安装create-react-app</span></span>
<span class="line"><span style="color:#FFCB6B;">create-react-app</span><span style="color:#A6ACCD;"> </span><span style="color:#C3E88D;">react-app</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;"># 创建一个名为react-app的React项目</span></span>
<span class="line"><span style="color:#676E95;font-style:italic;"># 删除node_modules package-lock.json</span></span>
<span class="line"><span style="color:#82AAFF;">cd</span><span style="color:#A6ACCD;"> </span><span style="color:#C3E88D;">react-app</span></span>
<span class="line"><span style="color:#FFCB6B;">pnpm</span><span style="color:#A6ACCD;"> </span><span style="color:#C3E88D;">i</span><span style="color:#A6ACCD;"> </span><span style="color:#676E95;font-style:italic;"># 使用pnpm重新安装依赖</span></span>
<span class="line"></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></div></div><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#676E95;font-style:italic;">// index.js</span></span>
<span class="line"><span style="color:#89DDFF;font-style:italic;">import</span><span style="color:#A6ACCD;"> ReactDOM </span><span style="color:#89DDFF;font-style:italic;">from</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">react-dom/client</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"><span style="color:#89DDFF;font-style:italic;">import</span><span style="color:#A6ACCD;"> App </span><span style="color:#89DDFF;font-style:italic;">from</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">./App</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C792EA;">const</span><span style="color:#A6ACCD;"> root </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> ReactDOM</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">createRoot</span><span style="color:#A6ACCD;">(document</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">querySelector</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">#root</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">root</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">render</span><span style="color:#A6ACCD;">(</span><span style="color:#89DDFF;">&lt;</span><span style="color:#FFCB6B;">App</span><span style="color:#89DDFF;"> /&gt;</span><span style="color:#A6ACCD;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#676E95;font-style:italic;">// App.jsx</span></span>
<span class="line"><span style="color:#89DDFF;font-style:italic;">import</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#F07178;"> </span><span style="color:#A6ACCD;">Component</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;font-style:italic;">from</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">react</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;font-style:italic;">export</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;font-style:italic;">default</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">class</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">App</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">extends</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">Component</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#F07178;">render</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Hello, React!</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></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></div></div><h3 id="react组件化开发" tabindex="-1">React组件化开发 <a class="header-anchor" href="#react组件化开发" aria-hidden="true">#</a></h3><ul><li>React组件生命周期</li><li>React组件间通信</li><li>React组件插槽</li><li>React非父子的通信</li><li>setState使用详解</li></ul><p>组件化是React的核心思想之一，组件化是一个抽象的过程，将大的应用程序抽象为多个小的组件，最终形成组件树</p><p>分而治之，让代码更容易组织和管理</p><p>React组件相对于Vue更加灵活多样，按照不同的方式可以分为多种组件</p><ul><li>根据组件定义方式，可以分为：函数组件(Functional Component)与类组件(Class Component)</li><li>根据组件内部是否有状态需要维护，可以分为：无状态组件(Stateless Component)和有状态组件(Stateful Component)</li><li>根据组件的不同职责，可以分为：展示型组件(Presentational Component)和容器型组件(Container Component)</li></ul><p>除此之外，还有异步组件、高阶组件等...</p><h3 id="类组件-1" tabindex="-1">类组件 <a class="header-anchor" href="#类组件-1" aria-hidden="true">#</a></h3><ul><li>类组件的定义有以下要求： <ul><li>组件的名称必须为大写（无论是类组件还是函数组件）</li><li>类组件需要继承自React.Component</li><li>类组件内必须实现render函数</li></ul></li><li>通过class关键字定义一个组件 <ul><li>constructor是可选的，通常需要在constructor中初始化一些数据</li><li>this.state中维护的数据就是组件内部的数据</li><li><strong>render方法是class组件中唯一必须实现的方法</strong></li></ul></li></ul><h4 id="render函数" tabindex="-1">render函数 <a class="header-anchor" href="#render函数" aria-hidden="true">#</a></h4><ul><li>render函数在组件第一次渲染时被调用</li><li>当<code>this.props</code>或<code>this.state</code>发生变化时被调用</li></ul><p>被调用时组件内会检查<code>this.props</code>和<code>this.state</code>是否发生变化，并且返回下面的返回值之一：</p><ul><li>React元素 <ul><li>通常通过JSX创建</li><li>例如<code>&lt;div /&gt;</code>会被React渲染为DOM节点，而<code>&lt;SomeComponent /&gt;</code>会被React渲染为自定义组件</li><li>无论是<code>&lt;div /&gt;</code>还是<code>&lt;SomeComponent /&gt;</code>，他们都为React元素</li></ul></li><li>数组或Fragments组件 <ul><li>允许通过render方法同时返回多个元素</li></ul></li><li>字符串或数字 <ul><li>元素会被渲染</li></ul></li><li>boolean/null/undefined类型 <ul><li>元素不会被渲染</li></ul></li></ul><h3 id="函数组件" tabindex="-1">函数组件 <a class="header-anchor" href="#函数组件" aria-hidden="true">#</a></h3><p>函数组件不需要继承自任何父类，函数的返回值相当于render函数的返回值，表示组件要渲染的内容</p><p>修改前文中编写的<code>App.jsx</code>即可：</p><div class="language-tsx line-numbers-mode"><button title="Copy Code" class="copy"></button><span class="lang">tsx</span><pre class="shiki material-theme-palenight"><code><span class="line"><span style="color:#676E95;font-style:italic;">// App.jsx</span></span>
<span class="line"><span style="color:#89DDFF;font-style:italic;">export</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;font-style:italic;">default</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">function</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">App</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#F07178;"> </span><span style="color:#89DDFF;font-style:italic;">return</span><span style="color:#F07178;"> </span><span style="color:#89DDFF;">&lt;</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;">Hello, React!</span><span style="color:#89DDFF;">&lt;/</span><span style="color:#F07178;">div</span><span style="color:#89DDFF;">&gt;</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></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></div></div><ul><li>函数组件是使用function定义的函数，函数的返回值会返回与render函数相同的内容，表示组件要渲染的内容</li><li>函数组件有自己的特点（在无hooks的情况下，引入hooks后函数组件与类组件一样强大） <ul><li>没有生命周期，也会被更新并挂在，但是没有生命周期函数</li><li>this关键字不能指向组件实例，因为没有组件实例</li><li>没有内部状态（state）</li></ul></li></ul><h3 id="组件的生命周期" tabindex="-1">组件的生命周期 <a class="header-anchor" href="#组件的生命周期" aria-hidden="true">#</a></h3><p>我们需要在组件的不同生命周期中执行不同的操作，比如添加解除监听器、发起网络请求等</p><p><img src="/assets/react-life-cycle.67e890c0.png" alt="React Life Cycle: https://projects.wojtekmaj.pl/react-lifecycle-methods-diagram/"></p><ul><li><code>componentDidMount</code> 组件挂载后</li><li><code>componentDidUpdate</code> 组件更新后</li><li><code>componentWillUnmount</code> 组件卸载前</li></ul></div></div></main><!--[--><!--]--><footer class="VPDocFooter" data-v-30dabfe4 data-v-cc0f9778><div class="edit-info" data-v-cc0f9778><div class="edit-link" data-v-cc0f9778><a class="VPLink link edit-link-button" href="https://github.com/ZiuChen/ZiuChen.github.io/edit/main/docs/note/React.md" target="_blank" rel="noreferrer" data-v-cc0f9778 data-v-8dd200cc><!--[--><svg xmlns="http://www.w3.org/2000/svg" viewbox="0 0 24 24" class="edit-link-icon" data-v-cc0f9778><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-cc0f9778><p class="VPLastUpdated" data-v-cc0f9778 data-v-de6a4e1f>Updated Date: <time datetime="2023-04-17T04:39:19.000Z" data-v-de6a4e1f></time></p></div></div><div class="prev-next" data-v-cc0f9778><div class="pager" data-v-cc0f9778><!----></div><div class="pager" data-v-cc0f9778><a class="pager-link next" href="/project/ClipboardManager/" data-v-cc0f9778><span class="desc" data-v-cc0f9778>Next page</span><span class="title" data-v-cc0f9778>超级剪贴板</span></a></div></div></footer><!--[--><!--]--></div></div></div></div></div><footer class="VPFooter has-sidebar" data-v-3af881ed data-v-8b655284><div class="container" data-v-8b655284><p class="message" data-v-8b655284>Released under the MIT License.</p><p class="copyright" data-v-8b655284>Copyright © 2019-present Ziu Chen</p></div></footer><!--[--><!--]--></div></div>
<script>__VP_HASH_MAP__ = JSON.parse("{\"project_clipboardmanager_index.md\":\"b114e887\",\"project_clipboardmanager_log_index.md\":\"dfa3a0a0\",\"project_clipboardmanager_statement_index.md\":\"042c09b5\",\"project_clipboardmanager_vip_index.md\":\"ac57a810\",\"project_markdown_index.md\":\"962f24ad\",\"project_markdown_log_index.md\":\"0a9099fd\",\"project_markdown_shortcut_index.md\":\"4a82e756\",\"project_smartwordbreak_index.md\":\"031fca6c\",\"project_smartwordbreak_log_index.md\":\"9a0f5e77\",\"project_smartwordbreak_statement_index.md\":\"5f2cc014\",\"self_index.md\":\"b7876723\",\"works_contribution.md\":\"684e9218\",\"works_opensource.md\":\"55f6b500\",\"note_javascript.md\":\"b9212d28\",\"article_【2023】青训营 - 前端练习题汇总解析.md\":\"4cd8991e\",\"article_【字节跳动】前端面试题总结.md\":\"e8edbefb\",\"article_【快手】深入理解前端面试题.md\":\"d2af855e\",\"article_【用友金融】前端面试题总结.md\":\"b76ce3fc\",\"article_一文读懂事件冒泡与事件捕获.md\":\"03c23783\",\"article_从0实现一个年度报告.md\":\"9dca0596\",\"article_彻底搞懂对象的数据属性描述符、存储属性描述符.md\":\"9b176b2a\",\"article_浅析defineproperty与proxy实现的双向绑定.md\":\"e08ddd5c\",\"article_深入理解proxy与reflect.md\":\"0209a1e3\",\"article_深入理解浏览器缓存机制.md\":\"8d5de362\",\"article_深入理解浏览器运行原理.md\":\"9380286d\",\"index.md\":\"ad735af1\",\"article_深入vue3源码，看看vue.use后究竟发生了什么？.md\":\"2aeef25a\",\"note_front-end engineering.md\":\"3c2274c5\",\"note_react.md\":\"7e023574\",\"article_深入javascript数据类型.md\":\"ba9615ca\",\"note_css.md\":\"5332045b\",\"note_javascriptenhanced.md\":\"addd568f\",\"article_一文读懂伪类与伪元素.md\":\"aefe5737\",\"article_一文读懂函数中this指向问题.md\":\"9e471304\",\"note_ssr.md\":\"a2182d15\",\"project_clipboardmanager_guide_index.md\":\"0ec1e04e\"}")</script>
<script type="module" async src="/assets/app.ab8d0b9f.js"></script>
</body>
</html>
Reference in New Issue View Git Blame Copy Permalink