astro/packages/integrations/markdoc/README.md

# @astrojs/markdoc (experimental) 📝

This **[Astro integration][astro-integration]** enables the usage of [Markdoc](https://markdoc.dev/) to create components, pages, and content collection entries.

- <strong>[Why Markdoc?](#why-markdoc)</strong>
- <strong>[Installation](#installation)</strong>
- <strong>[Usage](#usage)</strong>
- <strong>[Configuration](#configuration)</strong>
- <strong>[Examples](#examples)</strong>
- <strong>[Troubleshooting](#troubleshooting)</strong>
- <strong>[Contributing](#contributing)</strong>
- <strong>[Changelog](#changelog)</strong>

## Why Markdoc?

Markdoc allows you to enhance your Markdown with [Astro components][astro-components]. If you have existing content authored in Markdoc, this integration allows you to bring those files to your Astro project using content collections.

## 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.

```sh
# Using NPM
npx astro add markdoc
# Using Yarn
yarn astro add markdoc
# Using PNPM
pnpm astro add markdoc
```

If you run into any issues, [feel free to report them to us on GitHub](https://github.com/withastro/astro/issues) and try the manual installation steps below.

### Manual Install

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

```sh
npm install @astrojs/markdoc
```

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

```js ins={3} "markdoc()"
// astro.config.mjs
import { defineConfig } from 'astro/config';
import markdoc from '@astrojs/markdoc';

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

### Editor Integration

[VS Code](https://code.visualstudio.com/) supports Markdown by default. However, for Markdoc editor support, you may wish to add the following setting in your VSCode config. This ensures authoring Markdoc files provides a Markdown-like editor experience.

```json title=".vscode/settings.json"
{
  "files.associations": {
    "*.mdoc": "markdown"
  }
}
```

## Usage

Markdoc files can only be used within content collections. Add entries to any content collection using the `.mdoc` extension:

```sh
src/content/docs/
  why-markdoc.mdoc
  quick-start.mdoc
```

Then, query your collection using the [Content Collection APIs](https://docs.astro.build/en/guides/content-collections/#querying-collections):

```astro
---
import { getEntryBySlug } from 'astro:content';

const entry = await getEntryBySlug('docs', 'why-markdoc');
const { Content } = await entry.render();
---

<!--Access frontmatter properties with `data`-->
<h1>{entry.data.title}</h1>
<!--Render Markdoc contents with the Content component-->
<Content />
```

📚 See the [Astro Content Collection docs][astro-content-collections] for more information.

## Markdoc config

`@astrojs/markdoc` offers configuration options to use all of Markdoc's features and connect UI components to your content.

### Use Astro components as Markdoc tags

You can configure [Markdoc tags][markdoc-tags] that map to `.astro` components. You can add a new tag by creating a `markdoc.config.mjs|ts` file at the root of your project and configuring the `tag` attribute.

This example renders an `Aside` component, and allows a `type` prop to be passed as a string:

```js
// markdoc.config.mjs
import { defineMarkdocConfig, component } from '@astrojs/markdoc/config';

export default defineMarkdocConfig({
  tags: {
    aside: {
      render: component('./src/components/Aside.astro'),
      attributes: {
        // Markdoc requires type defs for each attribute.
        // These should mirror the `Props` type of the component
        // you are rendering.
        // See Markdoc's documentation on defining attributes
        // https://markdoc.dev/docs/attributes#defining-attributes
        type: { type: String },
      },
    },
  },
});
```

This component can now be used in your Markdoc files with the `{% aside %}` tag. Children will be passed to your component's default slot:

```md
# Welcome to Markdoc 👋

{% aside type="tip" %}

Use tags like this fancy "aside" to add some _flair_ to your docs.

{% /aside %}
```

### Use Astro components from npm packages and TypeScript files

You may need to use Astro components exposed as named exports from TypeScript or JavaScript files. This is common when using npm packages and design systems.

You can pass the import name as the second argument to the `component()` function:

```js
// markdoc.config.mjs
import { defineMarkdocConfig, component } from '@astrojs/markdoc/config';

export default defineMarkdocConfig({
  tags: {
    tabs: {
      render: component('@astrojs/starlight/components', 'Tabs'),
    },
  },
});
```

This generates the following import statement internally:

```ts
import { Tabs } from '@astrojs/starlight/components';
```

### Custom headings

`@astrojs/markdoc` automatically adds anchor links to your headings, and [generates a list of `headings` via the content collections API](https://docs.astro.build/en/guides/content-collections/#rendering-content-to-html). To further customize how headings are rendered, you can apply an Astro component [as a Markdoc node][markdoc-nodes].

This example renders a `Heading.astro` component using the `render` property:

```js
// markdoc.config.mjs
import { defineMarkdocConfig, nodes, component } from '@astrojs/markdoc/config';

export default defineMarkdocConfig({
  nodes: {
    heading: {
      ...nodes.heading, // Preserve default anchor link generation
      render: component('./src/components/Heading.astro'),
    },
  },
});
```

All Markdown headings will render the `Heading.astro` component and pass the following `attributes` as component props:

- `level: number` The heading level 1 - 6
- `id: string` An `id` generated from the heading's text contents. This corresponds to the `slug` generated by the [content `render()` function](https://docs.astro.build/en/guides/content-collections/#rendering-content-to-html).

For example, the heading `### Level 3 heading!` will pass `level: 3` and `id: 'level-3-heading'` as component props.

### Syntax highlighting

`@astrojs/markdoc` provides [Shiki](https://github.com/shikijs/shiki) and [Prism](https://github.com/PrismJS) extensions to highlight your code blocks.

#### Shiki

Apply the `shiki()` extension to your Markdoc config using the `extends` property. You can optionally pass a shiki configuration object:

```js
// markdoc.config.mjs
import { defineMarkdocConfig } from '@astrojs/markdoc/config';
import shiki from '@astrojs/markdoc/shiki';

export default defineMarkdocConfig({
  extends: [
    shiki({
      // Choose from Shiki's built-in themes (or add your own)
      // Default: 'github-dark'
      // https://github.com/shikijs/shiki/blob/main/docs/themes.md
      theme: 'dracula',
      // Enable word wrap to prevent horizontal scrolling
      // Default: false
      wrap: true,
      // Pass custom languages
      // Note: Shiki has countless langs built-in, including `.astro`!
      // https://github.com/shikijs/shiki/blob/main/docs/languages.md
      langs: [],
    }),
  ],
});
```

#### Prism

Apply the `prism()` extension to your Markdoc config using the `extends` property.

```js
// markdoc.config.mjs
import { defineMarkdocConfig } from '@astrojs/markdoc/config';
import prism from '@astrojs/markdoc/prism';

export default defineMarkdocConfig({
  extends: [prism()],
});
```

📚 To learn about configuring Prism stylesheets, [see our syntax highlighting guide](https://docs.astro.build/en/guides/markdown-content/#prism-configuration).

### Set the root HTML element

Markdoc wraps documents with an `<article>` tag by default. This can be changed from the `document` Markdoc node. This accepts an HTML element name or `null` if you prefer to remove the wrapper element:

```js
// markdoc.config.mjs
import { defineMarkdocConfig, nodes } from '@astrojs/markdoc/config';

export default defineMarkdocConfig({
  nodes: {
    document: {
      ...nodes.document, // Apply defaults for other options
      render: null, // default 'article'
    },
  },
});
```

### Custom Markdoc nodes / elements

You may want to render standard Markdown elements, such as paragraphs and bolded text, as Astro components. For this, you can configure a [Markdoc node][markdoc-nodes]. If a given node receives attributes, they will be available as component props.

This example renders blockquotes with a custom `Quote.astro` component:

```js
// markdoc.config.mjs
import { defineMarkdocConfig, nodes, component } from '@astrojs/markdoc/config';

export default defineMarkdocConfig({
  nodes: {
    blockquote: {
      ...nodes.blockquote, // Apply Markdoc's defaults for other options
      render: component('./src/components/Quote.astro'),
    },
  },
});
```

📚 [Find all of Markdoc's built-in nodes and node attributes on their documentation.](https://markdoc.dev/docs/nodes#built-in-nodes)

### Use client-side UI components

Tags and nodes are restricted to `.astro` files. To embed client-side UI components in Markdoc, [use a wrapper `.astro` component that renders a framework component](https://docs.astro.build/en/core-concepts/framework-components/#nesting-framework-components) with your desired `client:` directive.

This example wraps a React `Aside.tsx` component with a `ClientAside.astro` component:

```astro
---
// src/components/ClientAside.astro
import Aside from './Aside';
---

<Aside {...Astro.props} client:load />
```

This Astro component can now be passed to the `render` prop for any [tag][markdoc-tags] or [node][markdoc-nodes] in your config:

```js
// markdoc.config.mjs
import { defineMarkdocConfig, component } from '@astrojs/markdoc/config';

export default defineMarkdocConfig({
  tags: {
    aside: {
      render: component('./src/components/ClientAside.astro'),
      attributes: {
        type: { type: String },
      },
    },
  },
});
```

### Markdoc config

The `markdoc.config.mjs|ts` file accepts [all Markdoc configuration options](https://markdoc.dev/docs/config), including [tags](https://markdoc.dev/docs/tags) and [functions](https://markdoc.dev/docs/functions).

You can pass these options from the default export in your `markdoc.config.mjs|ts` file:

```js
// markdoc.config.mjs
import { defineMarkdocConfig } from '@astrojs/markdoc/config';

export default defineMarkdocConfig({
  functions: {
    getCountryEmoji: {
      transform(parameters) {
        const [country] = Object.values(parameters);
        const countryToEmojiMap = {
          japan: '🇯🇵',
          spain: '🇪🇸',
          france: '🇫🇷',
        };
        return countryToEmojiMap[country] ?? '🏳';
      },
    },
  },
});
```

Now, you can call this function from any Markdoc content entry:

```md
¡Hola {% getCountryEmoji("spain") %}!
```

📚 [See the Markdoc documentation](https://markdoc.dev/docs/functions#creating-a-custom-function) for more on using variables or functions in your content.

### Markdoc Language Server

If you are using VS Code, there is an official [Markdoc language extension](https://marketplace.visualstudio.com/items?itemName=Stripe.markdoc-language-support) that includes syntax highlighting and autocomplete for configured tags. [See the language server on GitHub](https://github.com/markdoc/language-server.git) for more information.

To set up the extension, create a `markdoc.config.json` file into the project root with following content:

```json
[
  {
    "id": "my-site",
    "path": "src/content",
    "schema": {
      "path": "markdoc.config.mjs",
      "type": "esm",
      "property": "default",
      "watch": true
    },
  }
]
```

The `schema` property contains all information to configure the language server for Astro content collections. It accepts following properties:

- `path`: The path to the configuration file.
- `type`: The type of module your configuration file uses (`esm` allows `import` syntax).
- `property`: The exported property name that contains the configuration object.
- `watch`: Tell the server to watch for changes in the configuration.

The top-level `path` property tells the server where content is located. Since Markdoc is specific to content collections, you can use `src/content`.

### Pass Markdoc variables

You may need to pass [variables][markdoc-variables] to your content. This is useful when passing SSR parameters like A/B tests.

Variables can be passed as props via the `Content` component:

```astro
---
import { getEntryBySlug } from 'astro:content';

const entry = await getEntryBySlug('docs', 'why-markdoc');
const { Content } = await entry.render();
---

<!--Pass the `abTest` param as a variable-->
<Content abTestGroup={Astro.params.abTestGroup} />
```

Now, `abTestGroup` is available as a variable in `docs/why-markdoc.mdoc`:

```md
{% if $abTestGroup === 'image-optimization-lover' %}

Let me tell you about image optimization...

{% /if %}
```

To make a variable global to all Markdoc files, you can use the `variables` attribute from your `markdoc.config.mjs|ts`:

```js
import { defineMarkdocConfig } from '@astrojs/markdoc/config';

export default defineMarkdocConfig({
  variables: {
    environment: process.env.IS_PROD ? 'prod' : 'dev',
  },
});
```

### Access frontmatter from your Markdoc content

To access frontmatter, you can pass the entry `data` property [as a variable](#pass-markdoc-variables) where you render your content:

```astro
---
import { getEntry } from 'astro:content';

const entry = await getEntry('docs', 'why-markdoc');
const { Content } = await entry.render();
---

<Content frontmatter={entry.data} />
```

This can now be accessed as `$frontmatter` in your Markdoc.

## Integration config options

The Astro Markdoc integration handles configuring Markdoc options and capabilities that are not available through the `markdoc.config.js` file.

### `allowHTML`

Enables writing HTML markup alongside Markdoc tags and nodes.

By default, Markdoc will not recognize HTML markup as semantic content.

To achieve a more Markdown-like experience, where HTML elements can be included alongside your content, set `allowHTML:true` as a `markdoc` integration option. This will enable HTML parsing in Markdoc markup.

```js {7} "allowHTML: true"
// astro.config.mjs
import { defineConfig } from 'astro/config';
import markdoc from '@astrojs/markdoc';

export default defineConfig({
  // ...
  integrations: [markdoc({ allowHTML: true })],
});
```

> **Warning**
> When `allowHTML` is enabled, HTML markup inside Markdoc documents will be rendered as actual HTML elements (including `<script>`), making attack vectors like XSS possible. Ensure that any HTML markup comes from trusted sources.

## Examples

- The [Astro Markdoc starter template](https://github.com/withastro/astro/tree/latest/examples/with-markdoc) shows how to use Markdoc files in your Astro project.

## Troubleshooting

For help, check out the `#support` channel on [Discord](https://astro.build/chat). Our friendly Support Squad members are here to help!

You can also check our [Astro Integration Documentation][astro-integration] 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](https://github.com/withastro/astro/tree/main/packages/integrations/markdoc/CHANGELOG.md) for a history of changes to this integration.

[astro-integration]: https://docs.astro.build/en/guides/integrations-guide/
[astro-components]: https://docs.astro.build/en/core-concepts/astro-components/
[astro-content-collections]: https://docs.astro.build/en/guides/content-collections/
[markdoc-tags]: https://markdoc.dev/docs/tags
[markdoc-nodes]: https://markdoc.dev/docs/nodes
[markdoc-variables]: https://markdoc.dev/docs/variables