astro/packages/integrations/mdx/README.md

@astrojs/mdx 📝

This Astro integration enables the usage of MDX components and allows you to create pages as .mdx files.

• Why MDX?
• Installation
• Usage
• Configuration
• Examples
• Troubleshooting
• Contributing
• Changelog

Why MDX?

MDX is the defacto solution for embedding components, such as interactive charts or alerts, within Markdown content. If you have existing content authored in MDX, this integration makes migrating to Astro a breeze.

Want to learn more about MDX before using this integration?
Check out “What is MDX?”, a deep-dive on the MDX format.

Installation

Quick Install

The astro add command-line tool automates the installation for you. Run one of the following commands in a new terminal window. (If you aren't sure which package manager you're using, run the first command.) Then, follow the prompts, and type "y" in the terminal (meaning "yes") for each one.

# Using NPM
npx astro add mdx
# Using Yarn
yarn astro add mdx
# Using PNPM
pnpx astro add mdx

Then, restart the dev server by typing CTRL-C and then npm run astro dev in the terminal window that was running Astro.

Because this command is new, it might not properly set things up. If that happens, feel free to log an issue on our GitHub and try the manual installation steps below.

Manual Install

First, install the @astrojs/mdx package using your package manager. If you're using npm or aren't sure, run this in the terminal:

npm install @astrojs/mdx

Then, apply this integration to your astro.config.* file using the integrations property:

astro.config.mjs

import { defineConfig } from 'astro/config';
import mdx from '@astrojs/mdx';

export default defineConfig({
  // ...
  integrations: [mdx()],
});

Finally, restart the dev server.

Usage

You can add MDX pages to your project by adding .mdx files within your src/pages/ directory.

Components

To use components in your MDX pages in Astro, head to our UI framework documentation. You'll explore:

• 📦 how framework components are loaded,
• 💧 client-side hydration options, and
• 🪆 opportunities to mix and nest frameworks together

Client Directives are still required in .mdx files.

Note

: .mdx files adhere to strict JSX syntax rather than Astro's HTML-like syntax.

Variables

MDX supports export statements to add variables to your templates. These variables are accessible both from the template itself and as named properties when importing the template somewhere else.

For instance, you can export a title field from an MDX page or component to use as a heading with {JSX expressions}:

export const title = 'My first MDX post'

# {title}

This title will be accessible from import and glob statements as well:

---
// src/pages/index.astro
const posts = await Astro.glob('./*.mdx');
---

{posts.map(post => <p>{post.title}</p>)}

See the official "how MDX works" guide for more on MDX variables.

Exported properties

Alongside your MDX variable exports, we generate a few helpful exports as well. These are accessible when importing an MDX file via import statements or Astro.glob.

file

The absolute path to the MDX file (e.g. home/user/projects/.../file.md).

url

The browser-ready URL for MDX files under src/pages/. For example, src/pages/en/about.mdx will provide a url of /en/about/. For MDX files outside of src/pages, url will be undefined.

getHeadings()

Returns: { depth: number; slug: string; text: string }[]

A function that returns an array of all headings (i.e. h1 -> h6 elements) in the MDX file. Each heading’s slug corresponds to the generated ID for a given heading and can be used for anchor links.

Frontmatter

Astro also supports YAML-based frontmatter out-of-the-box. By default, all variables declared in a frontmatter fence (---) will be accessible via the frontmatter export.

For example, we can add a title and publishDate to an MDX page or component like so:

---
title: 'My first MDX post'
publishDate: '21 September 2022'
---

# {frontmatter.title}

Now, this title and publishDate will be accessible from import and glob statements via the frontmatter property. This matches the behavior of plain markdown in Astro as well!

---
// src/pages/index.astro
const posts = await Astro.glob('./*.mdx');
---

{posts.map(post => (
  <Fragment>
    <h2>{post.frontmatter.title}</h2>
    <time>{post.frontmatter.publishDate}</time>
  </Fragment>
))}

Inject frontmatter via remark or rehype plugins

You may want to inject frontmatter properties across all of your MDX files. By using a remark or rehype plugin, you can generate these properties based on a file’s contents.

You can append to the data.astro.frontmatter property from your plugin’s file argument like so:

// example-remark-plugin.mjs
export function exampleRemarkPlugin() {
  // All remark and rehype plugins return a separate function
  return function (tree, file) {
    file.data.astro.frontmatter.customProperty = 'Generated property';
  }
}

After applying this plugin to your MDX integration config:

// astro.config.mjs
import mdx from '@astrojs/mdx';
import { exampleRemarkPlugin } from './example-remark-plugin.mjs';

export default {
  integrations: [
    mdx({
      remarkPlugins: [exampleRemarkPlugin],
    }),
  ],
};

…every MDX file will have customProperty in its frontmatter! See our Markdown documentation for more usage instructions and a reading time plugin example.

Layouts

Layouts can be applied in the same way as standard Astro Markdown. You can add a layout to your frontmatter like so:

---
layout: '../layouts/BaseLayout.astro' 
title: 'My Blog Post'
---

Then, you can retrieve all other frontmatter properties from your layout via the content property, and render your MDX using the default <slot />:

---
// src/layouts/BaseLayout.astro
const { content } = Astro.props;
---
<html>
  <head>
    <title>{content.title}</title>
  </head>
  <body>
    <h1>{content.title}</h1>
    <!-- Rendered MDX will be passed into the default slot. -->
    <slot />
  </body>
</html>

Importing layouts manually

You may need to pass information to your layouts that does not (or cannot) exist in your frontmatter. In this case, you can import and use a <Layout /> component like any other component:

---
// src/pages/posts/first-post.mdx

title: 'My first MDX post'
publishDate: '21 September 2022'
---
import BaseLayout from '../layouts/BaseLayout.astro';

function fancyJsHelper() {
  return "Try doing that with YAML!";
}

<BaseLayout title={frontmatter.title} fancyJsHelper={fancyJsHelper}>
  Welcome to my new Astro blog, using MDX!
</BaseLayout>

Then, your values are available to you through Astro.props in your layout, and your MDX content will be injected into the page where your <slot /> component is written:

---
// src/layouts/BaseLayout.astro
const { title, fancyJsHelper } = Astro.props;
---
<!-- -->
<h1>{title}</h1>
<slot />
<p>{fancyJsHelper()}</p>
<!-- -->

Syntax highlighting

The MDX integration respects your project's markdown.syntaxHighlight configuration.

We will highlight your code blocks with Shiki by default using Shiki twoslash. You can customize this remark plugin using the markdown.shikiConfig option in your astro.config. For example, you can apply a different built-in theme like so:

// astro.config.mjs
export default {
  markdown: {
    shikiConfig: {
      theme: 'dracula',
    },
  },
  integrations: [mdx()],
}

Visit our Shiki configuration docs for more on using Shiki with Astro.

Switch to Prism

You can also use the Prism syntax highlighter by setting markdown.syntaxHighlight to 'prism' in your astro.config like so:

// astro.config.mjs
export default {
  markdown: {
    syntaxHighlight: 'prism',
  },
  integrations: [mdx()],
}

This applies a minimal Prism renderer with added support for astro code blocks. Visit our "Prism configuration" docs for more on using Prism with Astro.

Configuration

remarkPlugins

Default plugins: remark-gfm, remark-smartypants

Remark plugins allow you to extend your Markdown with new capabilities. This includes auto-generating a table of contents, applying accessible emoji labels, and more. We encourage you to browse awesome-remark for a full curated list!

We apply GitHub-flavored Markdown and Smartypants by default. This brings some niceties like auto-generating clickable links from text (ex. https://example.com) and formatting quotes for readability. When applying your own plugins, you can choose to preserve or remove these defaults.

To apply plugins while preserving Astro's default plugins, use a nested extends object like so:

// astro.config.mjs
import remarkToc from 'remark-toc';

export default {
  integrations: [mdx({
    // apply remark-toc alongside GitHub-flavored markdown and Smartypants
    remarkPlugins: { extends: [remarkToc] },
  })],
}

To apply plugins without Astro's defaults, you can apply a plain array:

// astro.config.mjs
import remarkToc from 'remark-toc';

export default {
  integrations: [mdx({
    // apply remark-toc alone, removing other defaults
    remarkPlugins: [remarkToc],
  })],
}

rehypePlugins

Rehype plugins allow you to transform the HTML that your Markdown generates. We recommend checking the Remark plugin catalog first before considering rehype plugins, since most users want to transform their Markdown syntax instead. If HTML transforms are what you need, we encourage you to browse awesome-rehype for a full curated list of plugins!

We apply our own (non-overridable) collect-headings plugin. This applies IDs to all headings (i.e. h1 -> h6) in your MDX files to link to headings via anchor tags.

To apply additional rehype plugins, pass an array to the rehypePlugins option like so:

// astro.config.mjs
import rehypeMinifyHtml from 'rehype-minify';

export default {
  integrations: [mdx({
    rehypePlugins: [rehypeMinifyHtml],
  })],
}

Examples

• The Astro MDX example shows how to use MDX files in your Astro project.

Troubleshooting

For help, check out the #support-threads channel on Discord. Our friendly Support Squad members are here to help!

You can also check our Astro Integration Documentation for more on integrations.

Contributing

This package is maintained by Astro's Core team. You're welcome to submit an issue or PR!

Changelog

See CHANGELOG.md for a history of changes to this integration.