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详细介绍react中的NavLink组件包装优化

后端
react, javascript
3451 阅读

<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中，<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">NavLink</code>是<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">react-router-dom</code>库中的一个组件，用于创建具有明确<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">activeClassName</code>和<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">activeStyle</code>的导航链接。使用<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">NavLink</code>组件可以使页面的导航更加清晰和易于维护。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">然而，当在大型应用程序中使用<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">NavLink</code>组件时，可能会遇到性能问题。每个导航链接都是一个单独的组件，这可能会导致大量的组件渲染和内存占用。为了解决这个问题，可以使用“包装优化”技术来减少不必要的组件渲染和内存占用。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">包装优化是指在需要的时候才渲染组件，而不是在每次状态变化时都重新渲染整个组件树。通过这种方式，可以避免不必要的组件渲染和内存占用，提高应用程序的性能。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中，可以使用<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">React.memo</code>函数来进行包装优化。<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">React.memo</code>函数接受一个组件作为参数，并返回一个新的组件，该新组件会在状态发生变化时重新渲染，而在其他情况下使用缓存的结果。通过将<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">NavLink</code>组件包装在<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">React.memo</code>中，可以避免不必要的重新渲染。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">下面是一个示例代码，展示了如何使用<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">React.memo</code>进行包装优化：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-jsx" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import React from 'react';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import { NavLink } from 'react-router-dom';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import { memo } from 'react';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">const OptimizedNavLink = memo(props => {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">return <NavLink {...props} />;</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">});</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">export default OptimizedNavLink;</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在上面的代码中，我们使用<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">React.memo</code>将<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">NavLink</code>组件进行了包装。这样，只有当<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">props</code>发生变化时，才会重新渲染<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">OptimizedNavLink</code>组件。如果<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">props</code>没有发生变化，则使用缓存的结果，避免了不必要的重新渲染。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">使用包装优化技术可以提高应用程序的性能，减少不必要的组件渲染和内存占用。但是需要注意的是，包装优化技术并不是在所有情况下都是必需的，应该根据具体的应用场景和性能需求来决定是否使用。

详细介绍react中的react-router基本使用

后端
react, javascript
10805 阅读

<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React Router是React应用程序中常用的路由库，它可以帮助开发者实现页面之间的跳转和切换。在React Router中，主要有以下几个重要的概念：<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li>Router：一个应用中只有一个Router实例，所有路由配置组件Route都定义为Router的子组件。在Web应用中，我们一般会使用对Router进行包装的BrowserRouter或HashRouter两个组件。BrowserRouter使用HTML5的history API(pushState、replaceState等)实现应用的UI和URL的同步。HashRouter使用URL的hash实现应用的UI和URL同步。</li><li>Route：React Router中用于配置路由信息的组件，也是使用频率最高的组件。Route可以嵌套使用，path属性指定路由的匹配规则。</li><li>Link：用于在页面中创建导航链接的组件，它的props属性中有一个to属性，指定链接的目标地址。当点击Link组件时，会触发一个路由切换。</li><li>Switch：Switch组件用于在多个路由组件中选择渲染其中的一个。当匹配到多个路由时，Switch组件只会渲染第一个匹配到的Route组件。</li><li>Route with SubRoutes：在一些复杂的页面结构中，我们需要将一个页面拆分成多个子组件，每个子组件对应一个子路由。通过使用Route with SubRoutes，我们可以实现嵌套路由的功能。</li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React Router中，主要有以下几个重要的API：<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">history</code>：history是React Router提供的一个对象，它提供了对浏览器历史记录的操作方法，如pushState、replaceState等。通过使用history对象，我们可以实现页面的导航和URL的同步。</li><li><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">match</code>：在组件中可以通过this.props.match获取到当前路由的信息，如路径、参数等。通过match对象，我们可以根据不同的路由路径渲染不同的组件。</li><li><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">location</code>：location是React Router提供的一个对象，它包含了当前URL的信息，如路径、查询参数等。通过使用location对象，我们可以获取到当前页面的路径和查询参数。</li><li><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">staticContext</code>：staticContext是React Router提供的一个对象，它用于在组件中传递静态上下文信息。通过使用staticContext对象，我们可以将一些不经常变动的数据传递给子组件，避免重复渲染。</li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在使用React Router时，需要注意以下几点：<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li>在使用Link组件时，必须给定to属性，否则会抛出错误。</li><li>在使用Switch组件时，必须给定path属性，否则会渲染所有的Route组件。</li><li>在使用Route with SubRoutes时，必须给定子路由的path属性，否则会渲染所有的子组件。</li><li>在使用history对象时，必须给定basename属性，否则会导致路由路径不正确。</li><li>在使用location对象时，必须给定pathname属性，否则会导致获取不到当前页面的路径和查询参数。</li></ol>

详细介绍react中组件间通信的2种方式

后端
react, javascript
10807 阅读

<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中，组件间的通信主要有两种方式：<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li>通过props传递：这是父子组件之间通信的主要方式。在父组件中定义props属性，将数据或方法作为props的值传递给子组件。子组件可以通过props属性接收父组件传递的数据或方法。这种方式适用于将一般数据和函数数据传递给子组件，但只能一层一层传递，即单向单层传递。如果子组件需要向父组件传递数据，只能通过回调函数的方式进行。</li><li>消息订阅（subscribe）-发布（publish）机制：这种方式可以跨层级进行通信，使得任意两个组件通信成为可能。接收数据方为消息订阅（subscribe）者，数据发布（产生）方为消息发布（publish）者。订阅者通过监听发布者的消息，获取需要的数据。这种方式适用于需要跨层级通信或需要在任意两个组件之间传递数据的场景。</li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">以上是React中组件间通信的两种方式，根据具体的应用场景和需求选择合适的方式进行组件间的通信。

详细介绍react中ajax请求_使用fetch

后端
react, javascript
10800 阅读

<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中，可以使用Fetch API进行Ajax请求。Fetch API是现代浏览器内置的基于Promise的网络请求API，可以用于发起HTTP请求并获取响应。下面是一个使用Fetch API进行Ajax请求的示例：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-jsx" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import React, { useState, useEffect } from 'react';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">function Example() {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">const [data, setData] = useState(null);</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">useEffect(() => {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">fetch('https://api.example.com/data') // 发起Ajax请求  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">.then(response => response.json()) // 将响应解析为JSON格式  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">.then(data => setData(data)) // 将获取到的数据赋值给state变量  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">.catch(error => console.error('Error:', error)); // 捕获错误信息  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}, []); // 只在组件挂载时执行一次  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">return (</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><div>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">{data ? (</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><ul>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">{data.map(item => (</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><li key={item.id}>{item.name}</li>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">))}</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"></ul>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">) : (</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><p>Loading...</p>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">)}</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"></div>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">);</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在上面的示例中，我们使用了<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">useState</code>和<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">useEffect</code>两个React Hook。<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">useState</code>用于声明一个名为<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>的state变量，初始值为<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">null</code>。<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">useEffect</code>用于在组件挂载时执行Ajax请求，并将获取到的数据赋值给<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>变量。在组件中，我们通过判断<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>的值来决定展示什么内容：如果<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>不为空，则展示数据列表；如果<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>为空，则展示加载中的提示信息。通过Fetch API，我们可以很方便地进行Ajax请求并获取响应数据。

详细介绍react中ajax请求_使用axios

后端
react, javascript
10793 阅读

<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中，可以使用Axios库进行Ajax请求。Axios是一个基于Promise的HTTP库，可以用于浏览器和Node.js。它提供了一个简单、可扩展的API，使得发送HTTP请求变得非常容易。下面是一个使用Axios进行Ajax请求的示例：<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">首先，需要安装Axios库。可以使用npm或yarn进行安装：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-bash" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">npm install axios</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">或者<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-bash" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">yarn add axios</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">然后，可以在React组件中使用Axios发送HTTP请求。以下是一个使用Axios发送GET请求的示例：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-jsx" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import React, { useState, useEffect } from 'react';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import axios from 'axios';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">function Example() {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">const [data, setData] = useState(null);</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">useEffect(() => {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">axios.get('https://api.example.com/data') // 发送GET请求  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">.then(response => {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">setData(response.data); // 将响应数据赋值给state变量  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">})</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">.catch(error => {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">console.error('Error:', error); // 捕获错误信息  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">});</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}, []); // 只在组件挂载时执行一次  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">return (</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><div>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">{data ? (</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><ul>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">{data.map(item => (</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><li key={item.id}>{item.name}</li>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">))}</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"></ul>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">) : (</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><p>Loading...</p>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">)}</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"></div>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">);</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在上面的示例中，我们使用了<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">useState</code>和<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">useEffect</code>两个React Hook。<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">useState</code>用于声明一个名为<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>的state变量，初始值为<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">null</code>。<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">useEffect</code>用于在组件挂载时发送GET请求，并将响应数据赋值给<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>变量。在组件中，我们通过判断<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>的值来决定展示什么内容：如果<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>不为空，则展示数据列表；如果<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">data</code>为空，则展示加载中的提示信息。使用Axios库，我们可以很方便地进行Ajax请求并获取响应数据。

详细介绍react基于脚手架项目编写应用

后端
react, javascript
10810 阅读

<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React脚手架项目是一个预先配置好的项目模板，包含了开发React应用程序所需的基本文件和目录结构。通过使用脚手架项目，可以更快地创建React应用程序，并避免一些常见的配置问题。下面是一个基于React脚手架项目编写应用程序的详细步骤：<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li>安装Node.js和npm（Node.js的包管理器）。</li><li>使用npm安装React脚手架命令行工具（react-scripts）。</li></ol><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-bash" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">npm install -g create-react-app</td></tr></tbody></table></code></pre>3.使用create-react-app命令创建新的React脚手架项目。<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-lua" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">create-react-app my-app</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">此命令将创建一个名为“my-app”的新项目，并在当前目录下创建一个名为“my-app”的文件夹，其中包含了一个预先配置好的React应用程序。 4. 进入项目文件夹。<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-bash" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">cd my-app</td></tr></tbody></table></code></pre>5.启动开发服务器。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在项目文件夹中，运行以下命令启动开发服务器：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-arduino" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">npm start</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">此命令将启动一个开发服务器，并在浏览器中打开应用程序的主页。每当修改代码时，页面将自动重新加载。 6. 编写应用程序代码。 在项目文件夹中，可以看到以下几个文件夹和文件：<ul style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">src</code> 文件夹：用于存放应用程序的源代码。其中包含了 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">index.js</code> 文件（应用程序的入口点），以及一个名为 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">App.js</code> 的示例组件。</li><li><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">public</code> 文件夹：用于存放公共文件，如应用程序的外部样式表和图片等。其中包含了 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">index.html</code> 文件（应用程序的主页面）。</li><li><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">package.json</code> 文件：包含了项目的依赖项和脚本命令。</li><li><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">package-lock.json</code> 文件：包含了项目的依赖项版本信息。</li></ul>7.在 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">src</code> 文件夹中编写应用程序的组件代码。可以使用React组件来构建用户界面，并将组件导出为 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">index.js</code> 文件中的入口点。例如，创建一个名为 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">Welcome.js</code> 的组件：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-jsx" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import React from 'react';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">function Welcome(props) {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">return <h1>Hello, {props.name}</h1>;</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">export default Welcome;</td></tr></tbody></table></code></pre>8.在 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">index.js</code> 文件中导入组件并渲染应用程序：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-jsx" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import React from 'react';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import ReactDOM from 'react-dom';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import App from './App';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import Welcome from './Welcome';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">ReactDOM.render(</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><React.StrictMode>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><App />  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><Welcome name="Sara" />  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"></React.StrictMode>,</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">document.getElementById('root')</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">);</td></tr></tbody></table></code></pre>

详细介绍react使用react脚手架创建应用

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react, javascript
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<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">使用React脚手架创建React应用是一个相对直接的过程，下面是一个详细的步骤：<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li>安装Node.js和npm（Node.js的包管理器）。确保你的机器上已经安装了Node.js和npm。你可以从Node.js的官方网站上下载并安装。</li><li>安装React脚手架。你可以通过npm来全局安装React脚手架，命令如下：</li></ol><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-bash" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">npm install -g create-react-app</td></tr></tbody></table></code></pre>3使用React脚手架创建新的React应用。运行以下命令：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-lua" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">create-react-app my-app</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">这将在当前目录下创建一个名为“my-app”的新文件夹，其中包含了一个预先配置好的React应用程序。 4. 进入项目文件夹。在命令行中，转到新的项目文件夹：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-bash" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">cd my-app</td></tr></tbody></table></code></pre>5启动开发服务器。在项目文件夹中，你可以运行以下命令来启动开发服务器：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-arduino" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">npm start</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">这会启动一个开发服务器，并在浏览器中打开应用程序的主页。每当修改代码时，页面将自动重新加载。 6. 编写应用程序代码。在项目文件夹中，你会看到以下几个文件夹和文件： * <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">src</code> 文件夹：这是你的代码所在的地方，你可以在这里创建你的React组件和其他代码。 * <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">public</code> 文件夹：这个文件夹包含应用程序的公共文件，比如你的HTML文件和CSS文件。 * <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">package.json</code>：这个文件包含了项目的依赖项和脚本命令。 * <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">package-lock.json</code>：这个文件包含了项目的依赖项版本信息。 7. 在 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">src</code> 文件夹中编写你的React组件和其他代码。你可以使用React组件来构建用户界面，并将组件导出为 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">index.js</code> 文件中的入口点。例如，创建一个名为 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">Welcome.js</code> 的组件：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-jsx" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import React from 'react';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">function Welcome(props) {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">return <h1>Hello, {props.name}</h1>;</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">export default Welcome;</td></tr></tbody></table></code></pre>8在 <code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">index.js</code> 文件中导入你的组件并渲染应用程序：<pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-jsx" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import React from 'react';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import ReactDOM from 'react-dom';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import App from './App';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">import Welcome from './Welcome';</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">ReactDOM.render(</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><React.StrictMode>  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><App />  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><Welcome name="Sara" />  </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"></React.StrictMode>,</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">document.getElementById('root')</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"> </td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">);</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">以上就是使用React脚手架创建React应用的基本步骤。当然，你还可以根据项目的需要安装其他的依赖项或进行其他的配置。

详细介绍react脚手架应用分析

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react, javascript
10797 阅读

<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React脚手架（create-react-app）是一种流行的前端开发框架，它提供了一种快速构建React应用程序的开发环境。通过使用脚手架，开发者可以更容易地创建、开发和部署React应用程序。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">首先，React脚手架提供了一个完整的开发环境，包括Node.js、npm、Yarn等必要的工具和库。它还提供了构建工具（如Webpack）和代码编辑器（如Visual Studio Code）等开发工具，使得开发者可以更高效地进行开发。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">其次，React脚手架提供了一个可扩展的应用程序模板，包括基本的目录结构、代码库和配置文件等。开发者可以根据自己的需求进行定制和扩展，以满足应用程序的实际需求。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">此外，React脚手架还提供了一些内置的插件和工具，用于支持React特性和开发流程。例如，它支持热模块替换（HMR）技术，可以在开发过程中自动更新页面而无需重新加载整个页面。它还支持React路由、状态管理、Redux等常用的React特性和工具。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">最后，React脚手架还提供了可扩展性，允许开发者在脚手架的基础上添加自己的工具和库。例如，开发者可以使用脚手架提供的Webpack配置文件进行自定义配置，以满足特定的构建需求。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React脚手架提供了一种快速、高效且可扩展的前端开发环境，使得开发者可以更容易地创建、开发和部署React应用程序。它内置了许多常用的工具和库，同时也支持自定义和扩展，以满足不同应用程序的需求。

详细介绍react虚拟DOM和DOM diff算法

后端
react, javascript
10808 阅读

<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React虚拟DOM是一个抽象的树形结构，它通过与实际DOM进行对比，从而决定哪些节点需要更新。在React中，使用虚拟DOM的目的是为了减少不必要的DOM操作，从而提高应用程序的性能。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">DOM diff算法是React中用于比较虚拟DOM和实际DOM之间差异的算法。通过这个算法，React可以确定哪些节点需要更新，哪些节点需要保留，以及哪些节点需要新建。这个算法的主要思想是通过对两个树进行深度优先遍历来比较它们的差异，从而找到需要更新的部分。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中，diff算法的执行过程如下：<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li>首先，React会比较两个树的根节点。如果它们的类型（比如一个是div，另一个是span）或者属性不同，那么React就会销毁旧的树并新建一棵新的树。</li><li>如果两个树的类型和属性都相同，那么React就会保留旧的树，并只更新需要改变的部分。这个过程会一直递归地向下进行，直到找到需要更新的具体节点。</li><li>在找到需要更新的节点后，React会使用具体的DOM操作（比如appendChild、removeChild、innerHTML等）来更新DOM。</li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在执行diff算法时，React会考虑以下几个因素：<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li>节点的类型和属性；</li><li>节点的位置（比如它的父节点是谁，它在兄弟节点中的位置等）；</li><li>数据的变化（比如一个列表中的项增加了或减少了）。</li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">通过这种方式，React可以有效地减少不必要的DOM操作，从而提高应用程序的性能。同时，React还提供了开发者工具，使得开发者可以更方便地调试和优化应用程序的性能。

详细介绍react组件_生命周期总结

后端
react, javascript
21968 阅读

<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件的生命周期是指从组件被创建、使用到被销毁的整个过程。在这个过程中，React提供了自动执行的钩子函数，我们称之为生命周期函数。这些生命周期函数可以帮助我们更好地管理和控制组件的行为。<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中，组件的生命周期大致可以分为三个阶段：组件挂载阶段、组件更新阶段和组件销毁卸载阶段。<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li>挂载阶段：在组件挂载阶段，React会调用以下生命周期函数：</li><ul style="list-style-type: disc;" class=" list-paddingleft-2"><li>constructor：在组件创建之前被调用一次，用于初始化组件的状态和绑定事件处理函数。</li><li>componentDidMount：组件完成挂载后被调用，此时组件已经显示在页面上。这个方法通常用于执行一些只需要在组件挂载时执行一次的操作，如获取数据、订阅事件等。</li></ul><li>更新阶段：当组件的state或props发生变化时，React会重新渲染组件并调用以下生命周期函数：</li><ul style="list-style-type: disc;" class=" list-paddingleft-2"><li>getDerivedStateFromProps：在调用render方法之前被调用，用于根据传入的props派生出新的state。</li><li>render：组件的render方法根据state和props生成虚拟DOM。</li><li>componentDidUpdate：组件更新完成后被调用，此时组件已经更新并重新渲染完成。这个方法通常用于执行一些只需要在组件更新时执行一次的操作，如重新获取数据、重新订阅事件等。</li></ul><li>销毁卸载阶段：当组件被销毁时，React会调用以下生命周期函数：</li><ul style="list-style-type: disc;" class=" list-paddingleft-2"><li>componentWillUnmount：组件即将被销毁时被调用，用于执行一些需要在组件销毁前完成的操作，如取消订阅事件、清理资源等。</li></ul></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">以上就是React组件的生命周期及其中的主要生命周期函数。通过合理利用这些生命周期函数，我们可以更好地管理组件的状态和行为，提高应用程序的性能和可维护性。