MDX e React

Docusaurus has built-in support for MDX, which allows you to write JSX within your Markdown files and render them as React components.

Check out the MDX docs to see what fancy stuff you can do with MDX.

Debugging MDX

The MDX format is quite strict, and you may get compilation errors.

Use the MDX playground to debug them and make sure your syntax is valid.

info

Prettier, the most popular formatter, supports only the legacy MDX v1. If you get an unintentional formatting result, you may want to add {/* prettier-ignore */} before the problematic area, or add *.mdx to your .prettierignore, until Prettier has proper support for MDX v3. One of the main authors of MDX recommends remark-cli with remark-mdx.

Exporting components

To define any custom component within an MDX file, you have to export it: only paragraphs that start with export will be parsed as components instead of prose.

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

<Highlight color="#25c2a0">Docusaurus green</Highlight> and <Highlight color="#1877F2">Facebook blue</Highlight> are my favorite colors.

I can write **Markdown** alongside my _JSX_!

Notice how it renders both the markup from your React component and the Markdown syntax:

http://localhost:3000

Docusaurus green and Facebook blue are my favorite colors.

I can write Markdown alongside my JSX!

MDX is JSX

Since all doc files are parsed using MDX, anything that looks like HTML is actually JSX. Therefore, if you need to inline-style a component, follow JSX flavor and provide style objects.

/* Instead of this: */
<span style="background-color: red">Foo</span>
/* Use this: */
<span style={{backgroundColor: 'red'}}>Foo</span>

Importing components

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

<!-- Docusaurus theme component -->
import TOCInline from '@theme/TOCInline';
<!-- External component -->
import Button from '@mui/material/Button';
<!-- Custom component -->
import BrowserWindow from '@site/src/components/BrowserWindow';

tip

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 green</Highlight>

tip

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 component scope

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:

- a
- list!

And some <Highlight>custom markup</Highlight>...

It will be compiled to a React component containing ul, li, p, and Highlight elements. Highlight is not a native html element: you need to provide your own React component implementation for it.

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

If you swizzle this component, you will find all tags that have been implemented, and you can further customize our implementation by swizzling the respective sub-component, like @theme/MDXComponents/Code (which is used to render Markdown code blocks).

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';
// Import the original mapper
import MDXComponents from '@theme-original/MDXComponents';
import Highlight from '@site/src/components/Highlight';

export default {
  // Re-use the default mapping
  ...MDXComponents,
  // Map the "<Highlight>" tag to our Highlight component
  // `Highlight` will receive all props that were passed to `<Highlight>` in MDX
  Highlight,
};

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

I can conveniently use <Highlight color="#25c2a0">Docusaurus green</Highlight> everywhere!

http://localhost:3000

I can conveniently use Docusaurus green everywhere!

warning

We use upper-case tag names like Highlight on purpose.

From MDX v3+ onward (Docusaurus v3+), lower-case tag names are always rendered as native html elements, and will not use any component mapping you provide.

warning

This feature is powered by an MDXProvider. 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 and JSX interoperability

Docusaurus v3 is using MDX v3.

The MDX syntax is mostly compatible with CommonMark, but is much stricter because your .mdx files can use JSX and are compiled into real React components (check the playground).

Some valid CommonMark features won't work with MDX (more info), notably:

• Indented code blocks: use triple backticks instead
• Autolinks (<http://localhost:3000>): use regular link syntax instead ([http://localhost:3000](http://localhost:3000))
• HTML syntax (<p style="color: red;">): use JSX instead (<p style={{color: 'red'}}>)
• Unescaped { and <: escape them with \ instead (\{ and \<)

Experimental CommonMark support

Docusaurus v3 makes it possible to opt-in for a less strict, standard CommonMark support with the following options:

• The mdx.format: md front matter
• The .md file extension combined with the siteConfig.markdown.format: "detect" configuration

This feature is experimental and currently has a few limitations.

Importing code snippets

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

npm install --save raw-loader

Yarn

yarn add raw-loader

pnpm

pnpm add raw-loader

Bun

bun add 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.

note

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.

Importing Markdown

You can use Markdown files as components and import them elsewhere, either in Markdown files or in React pages. Each MDX file default-exports its page content as a React component. In the import statement, you can default-import this component with any name, but it must be capitalized following React's naming rules.

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>Hello {props.name}</span>

This is text some content from `_markdown-partial-example.mdx`.

someOtherDoc.mdx

import PartialExample from './_markdown-partial-example.mdx';

<PartialExample name="Sebastien" />

http://localhost:3000

Hello Sebastien

This is text some content from _markdown-partial-example.md.

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

Available exports

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

• frontMatter: the front matter as a record of string keys and values;
• toc: the table of contents, as a tree of headings. See also Inline TOC for a more concrete use-case.
• contentTitle: the Markdown title, which is the first h1 heading in the Markdown text. It's undefined if there isn't one (e.g. title specified in the front matter).

import TOCInline from '@theme/TOCInline';
import CodeBlock from '@theme/CodeBlock';

The table of contents for this page, serialized:

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

The front matter of this page:

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

<p>The title of this page is: <b>{contentTitle}</b></p>

http://localhost:3000

The table of contents for this page, serialized:

[
  {
    "value": "Exporting components",
    "id": "exporting-components",
    "level": 3
  },
  {
    "value": "Importing components",
    "id": "importing-components",
    "level": 3
  },
  {
    "value": "MDX component scope",
    "id": "mdx-component-scope",
    "level": 3
  },
  {
    "value": "Markdown and JSX interoperability",
    "id": "markdown-and-jsx-interoperability",
    "level": 3
  },
  {
    "value": "Importing code snippets",
    "id": "importing-code-snippets",
    "level": 2
  },
  {
    "value": "Importing Markdown",
    "id": "importing-markdown",
    "level": 2
  },
  {
    "value": "Available exports",
    "id": "available-exports",
    "level": 2
  }
]

The front matter of this page:

• id: react
• description: Usando o poder do React nos documentos do Docusaurus Markdown, graças ao MDX
• slug: /markdown-features/react

The title of this page is: MDX e React