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版本:2.3.1

MDX 和 React

在 Markdown 中使用 JSX

Docusaurus 原生支持 MDX v1,可以直接在 Markdown 文档中编写 JSX,并渲染为 React 组件。

备注

虽然 Docusaurus 会把 .md.mdx 都解析为 MDX,但第三方工具可能会对其中一些语法的处理略有不同。 为了得到最准确的解析结果和更好的编辑器支持,推荐包含 MDX 语法的文档使用 .mdx 后缀。

可以读读 MDX 的文档,看看 MDX 还能做哪些更神奇的事。

导出组件

要在 MDX 文件中自定义组件,你必须导出它:只有以 export 开头的段落才会被解析为组件,而不是文本。

export const Highlight = ({children, color}) => (
<span
style={{
backgroundColor: color,
borderRadius: '2px',
color: '#fff',
padding: '0.2rem',
}}>
{children}
</span>
);

<Highlight color="#25c2a0">Docusaurus 绿</Highlight><Highlight color="#1877F2">Facebook 蓝</Highlight> 是我最喜欢的颜色。

我可以把我的 _JSX_ 和 **Markdown** 写在一起!

注意它是怎么同时渲染 React 组件和 Markdown 语法的:

http://localhost:3000
Docusaurus 绿 Facebook 蓝 是我最喜欢的颜色。

我可以把我的 JSXMarkdown 写在一起!

MDX 仍然是 JSX

由于所有文件都使用 MDX 解析,所以任何看起来像 HTML 的文件实际上都是 JSX。 因此,如果想使用内联样式,要使用 JSX 语法,即给 style 的值设置为 JavaScript 对象。

/* 不要这么写: */
<span style="background-color: red">Foo</span>
/* 要这么写: */
<span style={{backgroundColor: 'red'}}>Foo</span>

This behavior is different from Docusaurus 1. See also Migrating from v1 to v2.

In addition, MDX is not 100% compatible with CommonMark. Use the MDX playground to ensure that your syntax is valid MDX.

导入组件

You can also import your own components defined in other files or third-party components installed via npm.

<!-- Docusaurus 主题组件 -->
import TOCInline from '@theme/TOCInline';
<!-- 外部组件 -->
import Button from '@mui/material/Button';
<!-- 自定义组件 -->
import BrowserWindow from '@site/src/components/BrowserWindow';
提示

The @site alias points to your website's directory, usually where the docusaurus.config.js file is. Using an alias instead of relative paths ('../../src/components/BrowserWindow') saves you from updating import paths when moving files around, or when versioning docs and translating.

While declaring components within Markdown is very convenient for simple cases, it becomes hard to maintain because of limited editor support, risks of parsing errors, and low reusability. Use a separate .js file when your component involves complex JS logic:

src/components/Highlight.js
import React from 'react';

export default function Highlight({children, color}) {
return (
<span
style={{
backgroundColor: color,
borderRadius: '2px',
color: '#fff',
padding: '0.2rem',
}}>
{children}
</span>
);
}
markdown-file.mdx
import Highlight from '@site/src/components/Highlight';

<Highlight color="#25c2a0">Docusaurus 绿</Highlight>
提示

If you use the same component across a lot of files, you don't need to import it everywhere—consider adding it to the global scope. See below

MDX 组件作用域

Apart from importing a component and exporting a component, a third way to use a component in MDX is to register it to the global scope, which will make it automatically available in every MDX file, without any import statements.

For example, given this MDX file:

- 一个
- 列表!

和一些 <highlight>自定义标记</highlight>……

It will be compiled to a React component containing ul, li, p, and highlight tags. Now, you can optionally provide your own implementation for any of these tags in the form of React components. (highlight isn't even an intrinsic element: it needs an implementation!)

In Docusaurus, this MDX component scope is provided by the @theme/MDXComponents component. It's not a React component, per se, unlike most other exports under the @theme/ alias: it is a record from tag names like ul and img to their custom implementations.

If you swizzle this component, you will find all tags that have been re-implemented, and you can further customize our implementation by swizzling the respective sub-component, like @theme/MDXComponents/Head (which is used to implement the <head> feature).

If you want to register extra tag names (like the <highlight> tag above), you should consider wrapping @theme/MDXComponents, so you don't have to maintain all the existing mappings. Since the swizzle CLI doesn't allow wrapping non-component files yet, you should manually create the wrapper:

src/theme/MDXComponents.js
import React from 'react';
// 导入原映射
import MDXComponents from '@theme-original/MDXComponents';
import Highlight from '@site/src/components/Highlight';

export default {
// 复用默认的映射
...MDXComponents,
// 把 "highlight" 标签映射到我们的 <Highlight /> 组件!
// `Highlight` 会收到在 MDX 中被传递给 `highlight` 的所有 props
highlight: Highlight,
};

And now, you can freely use <highlight> in every page, without writing the import statement:

我可以随时随地用 <highlight color="#25c2a0">Docusaurus 绿</highlight>了!
http://localhost:3000

我可以随时随地用 Docusaurus 绿了!

信息

We use lower-case tag names like highlight to "pretend" that they are intrinsic elements, but you can use capitalized ones like Highlight as well.

注意

This feature is powered by a wrapper provider. If you are importing Markdown in a React page, you have to supply this provider yourself through the MDXContent theme component.

src/pages/index.js
import React from 'react';
import FeatureDisplay from './_featureDisplay.mdx';
import MDXContent from '@theme/MDXContent';

export default function LandingPage() {
return (
<div>
<MDXContent>
<FeatureDisplay />
</MDXContent>
</div>
);
}

If you don't wrap your imported MDX with MDXContent, the global scope will not be available.

Markdown 和 JSX 的交互

Docusaurus v2 is using MDX v1, which has a lot of known cases where the content fails to be correctly parsed as Markdown. Use the MDX playground to ensure that your syntax is valid MDX.

Samples of parsing failures

A paragraph starting with a JSX tag will be seen entirely as a JSX string:

<span style={{color: 'red'}}>高亮文本</span> 但之后_Markdown_ 就**无法工作**
http://localhost:3000
高亮文本 但之后 _Markdown_ 就**无法工作**了

JSX 标签里的 Markdown 永远不会工作:

<span style={{color: 'red'}}>**粗体不起作用**</span>
http://localhost:3000
**粗体不起作用**

在一个 JSX 标签正下方的文本会被当作 JSX 文本:

<div style={{color: 'red'}}>
**粗体还是不起作用**
</div>
http://localhost:3000
**粗体还是不起作用**

被缩进四格的 Markdown 文本会被当作代码块:

<div style={{color: 'red'}}>

You may think I'm just some text...

</div>
http://localhost:3000
你可能以为我只是一些文本……

导入代码片段

You can not only import a file containing a component definition, but also import any code file as raw text, and then insert it in a code block, thanks to Webpack raw-loader. In order to use raw-loader, you first need to install it in your project:

npm install --save raw-loader

Now you can import code snippets from another file as it is:

myMarkdownFile.mdx
import CodeBlock from '@theme/CodeBlock';
import MyComponentSource from '!!raw-loader!./myComponent';

<CodeBlock language="jsx">{MyComponentSource}</CodeBlock>
http://localhost:3000
/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/

import React, {useState} from 'react';

export default function MyComponent() {
const [bool, setBool] = useState(false);
return (
<div>
<p>MyComponent rendered !</p>
<p>bool={bool ? 'true' : 'false'}</p>
<p>
<button onClick={() => setBool((b) => !b)}>toggle bool</button>
</p>
</div>
);
}

See using code blocks in JSX for more details of the <CodeBlock> component.

备注

You have to use <CodeBlock> rather than the Markdown triple-backtick ```, because the latter will ship out any of its content as-is, but you want to interpolate the imported text here.

warning

This feature is experimental and might be subject to breaking API changes in the future.

导入 Markdown

You can use Markdown files as components and import them elsewhere, either in Markdown files or in React pages.

By convention, using the _ filename prefix will not create any doc page and means the Markdown file is a "partial", to be imported by other files.

_markdown-partial-example.mdx
<span>你好 {props.name}</span>

这是一些来自 `_markdown-partial-example.mdx` 的内容。
someOtherDoc.mdx
import PartialExample from './_markdown-partial-example.mdx';

<PartialExample name="Sebastien" />
http://localhost:3000
你好 思达

这是来自 _markdown-partial-example.md 的一些文本。

This way, you can reuse content among multiple pages and avoid duplicating materials.

注意

Currently, the table of contents does not contain the imported Markdown headings. This is a technical limitation that we are trying to solve (issue).

全局导出项

Within the MDX page, the following variables are available as globals:

  • frontMatter:Markdown 文档的前言,包含字符串键和对应的值;
  • toc:目录,作为一个标题列表。 这个变量的实际用法可以参考内联目录
  • contentTitle:Markdown 文档标题,即文档中的第一个 h1 标题。 如果没有则是 undefined,例如把标题定义在了文档的 title 前言中。
import TOCInline from '@theme/TOCInline';
import CodeBlock from '@theme/CodeBlock';

这一页的目录,经过序列化:

<CodeBlock className="language-json">{JSON.stringify(toc, null, 2)}</CodeBlock>

这一页的前言:

<ul>
{Object.entries(frontMatter).map(([key, value]) => <li key={key}><b>{key}</b>: {value}</li>)}
</ul>

<p>这一页的标题是: <b>{contentTitle}</b></p>
http://localhost:3000

这一页的目录,经过序列化:

[
{
"value": "在 Markdown 中使用 JSX",
"id": "using-jsx-in-markdown",
"level": 2
},
{
"value": "导出组件",
"id": "exporting-components",
"level": 3
},
{
"value": "导入组件",
"id": "importing-components",
"level": 3
},
{
"value": "MDX 组件作用域",
"id": "mdx-component-scope",
"level": 3
},
{
"value": "Markdown 和 JSX 的交互",
"id": "markdown-and-jsx-interoperability",
"level": 3
},
{
"value": "导入代码片段",
"id": "importing-code-snippets",
"level": 2
},
{
"value": "导入 Markdown",
"id": "importing-markdown",
"level": 2
},
{
"value": "全局导出项",
"id": "available-exports",
"level": 2
}
]

这一页的前言:

  • id: react
  • description: 得益于 MDX,你可以在 Docusaurus Markdown 文档中使用 React
  • slug: /markdown-features/react

这一页的标题:MDX 和 React