vitepress/docs/en/guide/markdown.md

# Markdown Extensions

VitePress comes with built in Markdown Extensions.

## Header Anchors

Headers automatically get anchor links applied. Rendering of anchors can be configured using the `markdown.anchor` option.

### Custom anchors

To specify a custom anchor tag for a heading instead of using the auto-generated one, add a suffix to the heading:

```
# Using custom anchors {#my-anchor}
```

This allows you to link to the heading as `#my-anchor` instead of the default `#using-custom-anchors`.

## Links

Both internal and external links get special treatment.

### Internal Links

Internal links are converted to router links for SPA navigation. Also, every `index.md` contained in each sub-directory will automatically be converted to `index.html`, with corresponding URL `/`.

For example, given the following directory structure:

```
.
├─ index.md
├─ foo
│  ├─ index.md
│  ├─ one.md
│  └─ two.md
└─ bar
   ├─ index.md
   ├─ three.md
   └─ four.md
```

And providing you are in `foo/one.md`:

```md
[Home](/) <!-- sends the user to the root index.md -->
[foo](/foo/) <!-- sends the user to index.html of directory foo -->
[foo heading](./#heading) <!-- anchors user to a heading in the foo index file -->
[bar - three](../bar/three) <!-- you can omit extension -->
[bar - three](../bar/three.md) <!-- you can append .md -->
[bar - four](../bar/four.html) <!-- or you can append .html -->
```

### Page Suffix

Pages and internal links get generated with the `.html` suffix by default.

### External Links

Outbound links automatically get `target="_blank" rel="noreferrer"`:

- [vuejs.org](https://vuejs.org)
- [VitePress on GitHub](https://github.com/vuejs/vitepress)

## Frontmatter

[YAML frontmatter](https://jekyllrb.com/docs/front-matter/) is supported out of the box:

```yaml
---
title: Blogging Like a Hacker
lang: en-US
---
```

This data will be available to the rest of the page, along with all custom and theming components.

For more details, see [Frontmatter](../reference/frontmatter-config).

## GitHub-Style Tables

**Input**

```md
| Tables        |      Are      |  Cool |
| ------------- | :-----------: | ----: |
| col 3 is      | right-aligned | $1600 |
| col 2 is      |   centered    |   $12 |
| zebra stripes |   are neat    |    $1 |
```

**Output**

| Tables        |      Are      |   Cool |
| ------------- | :-----------: | -----: |
| col 3 is      | right-aligned | \$1600 |
| col 2 is      |   centered    |   \$12 |
| zebra stripes |   are neat    |    \$1 |

## Emoji :tada:

**Input**

```
:tada: :100:
```

**Output**

:tada: :100:

A [list of all emojis](https://github.com/markdown-it/markdown-it-emoji/blob/master/lib/data/full.mjs) is available.

## Table of Contents

**Input**

```
[[toc]]
```

**Output**

[[toc]]

Rendering of the TOC can be configured using the `markdown.toc` option.

## Custom Containers

Custom containers can be defined by their types, titles, and contents.

### Default Title

**Input**

```md
::: info
This is an info box.
:::

::: tip
This is a tip.
:::

::: warning
This is a warning.
:::

::: danger
This is a dangerous warning.
:::

::: details
This is a details block.
:::
```

**Output**

::: info
This is an info box.
:::

::: tip
This is a tip.
:::

::: warning
This is a warning.
:::

::: danger
This is a dangerous warning.
:::

::: details
This is a details block.
:::

### Custom Title

You may set custom title by appending the text right after the "type" of the container.

**Input**

````md
::: danger STOP
Danger zone, do not proceed
:::

::: details Click me to toggle the code
```js
console.log('Hello, VitePress!')
```
:::
````

**Output**

::: danger STOP
Danger zone, do not proceed
:::

::: details Click me to toggle the code
```js
console.log('Hello, VitePress!')
```
:::

Also, you may set custom titles globally by adding the following content in site config, helpful if not writing in English:

```ts
// config.ts
export default defineConfig({
  // ...
  markdown: {
    container: {
      tipLabel: '提示',
      warningLabel: '警告',
      dangerLabel: '危险',
      infoLabel: '信息',
      detailsLabel: '详细信息'
    }
  }
  // ...
})
```

### Additional Attributes

You can add additional attributes to the custom containers. We use [markdown-it-attrs](https://github.com/arve0/markdown-it-attrs) for this feature, and it is supported on almost all markdown elements. For example, you can set the `open` attribute to make the details block open by default:

**Input**

````md
::: details Click me to toggle the code {open}
```js
console.log('Hello, VitePress!')
```
:::
````

**Output**

::: details Click me to toggle the code {open}
```js
console.log('Hello, VitePress!')
```
:::

### `raw`

This is a special container that can be used to prevent style and router conflicts with VitePress. This is especially useful when you're documenting component libraries. You might also wanna check out [whyframe](https://whyframe.dev/docs/integrations/vitepress) for better isolation.

**Syntax**

```md
::: raw
Wraps in a `<div class="vp-raw">`
:::
```

`vp-raw` class can be directly used on elements too. Style isolation is currently opt-in:

- Install `postcss` with your preferred package manager:

  ```sh
  $ npm add -D postcss
  ```

- Create a file named `docs/postcss.config.mjs` and add this to it:

  ```js
  import { postcssIsolateStyles } from 'vitepress'

  export default {
    plugins: [postcssIsolateStyles()]
  }
  ```

  You can pass its options like this:

  ```js
  postcssIsolateStyles({
    includeFiles: [/custom\.css/] // defaults to [/vp-doc\.css/, /base\.css/]
  })
  ```

## GitHub-flavored Alerts

VitePress also supports [GitHub-flavored alerts](https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax#alerts) to render as callouts. They will be rendered the same as the [custom containers](#custom-containers).

```md
> [!NOTE]
> Highlights information that users should take into account, even when skimming.

> [!TIP]
> Optional information to help a user be more successful.

> [!IMPORTANT]
> Crucial information necessary for users to succeed.

> [!WARNING]
> Critical content demanding immediate user attention due to potential risks.

> [!CAUTION]
> Negative potential consequences of an action.
```

> [!NOTE]
> Highlights information that users should take into account, even when skimming.

> [!TIP]
> Optional information to help a user be more successful.

> [!IMPORTANT]
> Crucial information necessary for users to succeed.

> [!WARNING]
> Critical content demanding immediate user attention due to potential risks.

> [!CAUTION]
> Negative potential consequences of an action.

## Syntax Highlighting in Code Blocks

VitePress uses [Shiki](https://github.com/shikijs/shiki) to highlight language syntax in Markdown code blocks, using coloured text. Shiki supports a wide variety of programming languages. All you need to do is append a valid language alias to the beginning backticks for the code block:

**Input**

````
```js
export default {
  name: 'MyComponent',
  // ...
}
```
````

````
```html
<ul>
  <li v-for="todo in todos" :key="todo.id">
    {{ todo.text }}
  </li>
</ul>
```
````

**Output**

```js
export default {
  name: 'MyComponent'
  // ...
}
```

```html
<ul>
  <li v-for="todo in todos" :key="todo.id">
    {{ todo.text }}
  </li>
</ul>
```

A [list of valid languages](https://shiki.style/languages) is available on Shiki's repository.

You may also customize syntax highlight theme in app config. Please see [`markdown` options](../reference/site-config#markdown) for more details.

## Line Highlighting in Code Blocks

**Input**

````
```js{4}
export default {
  data () {
    return {
      msg: 'Highlighted!'
    }
  }
}
```
````

**Output**

```js{4}
export default {
  data () {
    return {
      msg: 'Highlighted!'
    }
  }
}
```

In addition to a single line, you can also specify multiple single lines, ranges, or both:

- Line ranges: for example `{5-8}`, `{3-10}`, `{10-17}`
- Multiple single lines: for example `{4,7,9}`
- Line ranges and single lines: for example `{4,7-13,16,23-27,40}`

**Input**

````
```js{1,4,6-8}
export default { // Highlighted
  data () {
    return {
      msg: `Highlighted!
      This line isn't highlighted,
      but this and the next 2 are.`,
      motd: 'VitePress is awesome',
      lorem: 'ipsum'
    }
  }
}
```
````

**Output**

```js{1,4,6-8}
export default { // Highlighted
  data () {
    return {
      msg: `Highlighted!
      This line isn't highlighted,
      but this and the next 2 are.`,
      motd: 'VitePress is awesome',
      lorem: 'ipsum',
    }
  }
}
```

Alternatively, it's possible to highlight directly in the line by using the `// [!code highlight]` comment.

**Input**

````
```js
export default {
  data () {
    return {
      msg: 'Highlighted!' // [!!code highlight]
    }
  }
}
```
````

**Output**

```js
export default {
  data() {
    return {
      msg: 'Highlighted!' // [!code highlight]
    }
  }
}
```

## Focus in Code Blocks

Adding the `// [!code focus]` comment on a line will focus it and blur the other parts of the code.

Additionally, you can define a number of lines to focus using `// [!code focus:<lines>]`.

**Input**

````
```js
export default {
  data () {
    return {
      msg: 'Focused!' // [!!code focus]
    }
  }
}
```
````

**Output**

```js
export default {
  data() {
    return {
      msg: 'Focused!' // [!code focus]
    }
  }
}
```

## Colored Diffs in Code Blocks

Adding the `// [!code --]` or `// [!code ++]` comments on a line will create a diff of that line, while keeping the colors of the codeblock.

**Input**

````
```js
export default {
  data () {
    return {
      msg: 'Removed' // [!!code --]
      msg: 'Added' // [!!code ++]
    }
  }
}
```
````

**Output**

```js
export default {
  data () {
    return {
      msg: 'Removed' // [!code --]
      msg: 'Added' // [!code ++]
    }
  }
}
```

## Errors and Warnings in Code Blocks

Adding the `// [!code warning]` or `// [!code error]` comments on a line will color it accordingly.

**Input**

````
```js
export default {
  data () {
    return {
      msg: 'Error', // [!!code error]
      msg: 'Warning' // [!!code warning]
    }
  }
}
```
````

**Output**

```js
export default {
  data() {
    return {
      msg: 'Error', // [!code error]
      msg: 'Warning' // [!code warning]
    }
  }
}
```

## Line Numbers

You can enable line numbers for each code blocks via config:

```js
export default {
  markdown: {
    lineNumbers: true
  }
}
```

Please see [`markdown` options](../reference/site-config#markdown) for more details.

You can add `:line-numbers` / `:no-line-numbers` mark in your fenced code blocks to override the value set in config.

You can also customize the starting line number by adding `=` after `:line-numbers`. For example, `:line-numbers=2` means the line numbers in code blocks will start from `2`.

**Input**

````md
```ts {1}
// line-numbers is disabled by default
const line2 = 'This is line 2'
const line3 = 'This is line 3'
```

```ts:line-numbers {1}
// line-numbers is enabled
const line2 = 'This is line 2'
const line3 = 'This is line 3'
```

```ts:line-numbers=2 {1}
// line-numbers is enabled and start from 2
const line3 = 'This is line 3'
const line4 = 'This is line 4'
```
````

**Output**

```ts {1}
// line-numbers is disabled by default
const line2 = 'This is line 2'
const line3 = 'This is line 3'
```

```ts:line-numbers {1}
// line-numbers is enabled
const line2 = 'This is line 2'
const line3 = 'This is line 3'
```

```ts:line-numbers=2 {1}
// line-numbers is enabled and start from 2
const line3 = 'This is line 3'
const line4 = 'This is line 4'
```

## Import Code Snippets

You can import code snippets from existing files via following syntax:

```md
<<< @/filepath
```

It also supports [line highlighting](#line-highlighting-in-code-blocks):

```md
<<< @/filepath{highlightLines}
```

**Input**

```md
<<< @/snippets/snippet.js{2}
```

**Code file**

<<< @/snippets/snippet.js

**Output**

<<< @/snippets/snippet.js{2}

::: tip
The value of `@` corresponds to the source root. By default it's the VitePress project root, unless `srcDir` is configured. Alternatively, you can also import from relative paths:

```md
<<< ../snippets/snippet.js
```

:::

You can also use a [VS Code region](https://code.visualstudio.com/docs/editor/codebasics#_folding) to only include the corresponding part of the code file. You can provide a custom region name after a `#` following the filepath:

**Input**

```md
<<< @/snippets/snippet-with-region.js#snippet{1}
```

**Code file**

<<< @/snippets/snippet-with-region.js

**Output**

<<< @/snippets/snippet-with-region.js#snippet{1}

You can also specify the language inside the braces (`{}`) like this:

```md
<<< @/snippets/snippet.cs{c#}

<!-- with line highlighting: -->

<<< @/snippets/snippet.cs{1,2,4-6 c#}

<!-- with line numbers: -->

<<< @/snippets/snippet.cs{1,2,4-6 c#:line-numbers}
```

This is helpful if source language cannot be inferred from your file extension.

## Code Groups

You can group multiple code blocks like this:

**Input**

````md
::: code-group

```js [config.js]
/**
 * @type {import('vitepress').UserConfig}
 */
const config = {
  // ...
}

export default config
```

```ts [config.ts]
import type { UserConfig } from 'vitepress'

const config: UserConfig = {
  // ...
}

export default config
```

:::
````

**Output**

::: code-group

```js [config.js]
/**
 * @type {import('vitepress').UserConfig}
 */
const config = {
  // ...
}

export default config
```

```ts [config.ts]
import type { UserConfig } from 'vitepress'

const config: UserConfig = {
  // ...
}

export default config
```

:::

You can also [import snippets](#import-code-snippets) in code groups:

**Input**

```md
::: code-group

<!-- filename is used as title by default -->

<<< @/snippets/snippet.js

<!-- you can provide a custom one too -->

<<< @/snippets/snippet-with-region.js#snippet{1,2 ts:line-numbers} [snippet with region]

:::
```

**Output**

::: code-group

<<< @/snippets/snippet.js

<<< @/snippets/snippet-with-region.js#snippet{1,2 ts:line-numbers} [snippet with region]

:::

## Markdown File Inclusion

You can include a markdown file in another markdown file, even nested.

::: tip
You can also prefix the markdown path with `@`, and it will act as the source root. By default, the source root is the VitePress project root, unless `srcDir` is configured.
:::

For example, you can include a relative markdown file using this:

**Input**

```md
# Docs

## Basics

<!--@include: ./parts/basics.md-->
```

**Part file** (`parts/basics.md`)

```md
Some getting started stuff.

### Configuration

Can be created using `.foorc.json`.
```

**Equivalent code**

```md
# Docs

## Basics

Some getting started stuff.

### Configuration

Can be created using `.foorc.json`.
```

It also supports selecting a line range:

**Input**

```md:line-numbers
# Docs

## Basics

<!--@include: ./parts/basics.md{3,}-->
```

**Part file** (`parts/basics.md`)

```md:line-numbers
Some getting started stuff.

### Configuration

Can be created using `.foorc.json`.
```

**Equivalent code**

```md:line-numbers
# Docs

## Basics

### Configuration

Can be created using `.foorc.json`.
```

The format of the selected line range can be: `{3,}`, `{,10}`, `{1,10}`

You can also use a [VS Code region](https://code.visualstudio.com/docs/editor/codebasics#_folding) to only include the corresponding part of the code file. You can provide a custom region name after a `#` following the filepath:

**Input**

```md:line-numbers
# Docs

## Basics

<!--@include: ./parts/basics.md#basic-usage{,2}-->
<!--@include: ./parts/basics.md#basic-usage{5,}-->
```

**Part file** (`parts/basics.md`)

```md:line-numbers
<!-- #region basic-usage -->
## Usage Line 1

## Usage Line 2

## Usage Line 3
<!-- #endregion basic-usage -->
```

**Equivalent code**

```md:line-numbers
# Docs

## Basics

## Usage Line 1

## Usage Line 3
```

::: warning
Note that this does not throw errors if your file is not present. Hence, when using this feature make sure that the contents are being rendered as expected.
:::

Instead of VS Code regions, you can also use header anchors to include a specific section of the file. For example, if you have a header in your markdown file like this:

```md
## My Base Section

Some content here.

### My Sub Section

Some more content here.

## Another Section

Content outside `My Base Section`.
```

You can include the `My Base Section` section like this:

```md
## My Extended Section
<!--@include: ./parts/basics.md#my-base-section-->
```

**Equivalent code**

```md
## My Extended Section

Some content here.

### My Sub Section

Some more content here.
```

Here, `my-base-section` is the generated id of the heading element. In case it's not easily guessable, you can open the part file in your browser and click on the heading anchor (`#` symbol left to the heading when hovered) to see the id in the URL bar. Or use browser dev tools to inspect the element. Alternatively, you can also specify the id to the part file like this:

```md
## My Base Section {#custom-id}
```

and include it like this:

```md
<!--@include: ./parts/basics.md#custom-id-->
```

## Math Equations

This is currently opt-in. To enable it, you need to install `markdown-it-mathjax3` and set `markdown.math` to `true` in your config file:

```sh
npm add -D markdown-it-mathjax3
```

```ts [.vitepress/config.ts]
export default {
  markdown: {
    math: true
  }
}
```

**Input**

```md
When $a \ne 0$, there are two solutions to $(ax^2 + bx + c = 0)$ and they are
$$ x = {-b \pm \sqrt{b^2-4ac} \over 2a} $$

**Maxwell's equations:**

| equation                                                                                                                                                                  | description                                                                            |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------- |
| $\nabla \cdot \vec{\mathbf{B}}  = 0$                                                                                                                                      | divergence of $\vec{\mathbf{B}}$ is zero                                               |
| $\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t}  = \vec{\mathbf{0}}$                                                          | curl of $\vec{\mathbf{E}}$ is proportional to the rate of change of $\vec{\mathbf{B}}$ |
| $\nabla \times \vec{\mathbf{B}} -\, \frac1c\, \frac{\partial\vec{\mathbf{E}}}{\partial t} = \frac{4\pi}{c}\vec{\mathbf{j}}    \nabla \cdot \vec{\mathbf{E}} = 4 \pi \rho$ | _wha?_                                                                                 |
```

**Output**

When $a \ne 0$, there are two solutions to $(ax^2 + bx + c = 0)$ and they are
$$ x = {-b \pm \sqrt{b^2-4ac} \over 2a} $$

**Maxwell's equations:**

| equation                                                                                                                                                                  | description                                                                            |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------- |
| $\nabla \cdot \vec{\mathbf{B}}  = 0$                                                                                                                                      | divergence of $\vec{\mathbf{B}}$ is zero                                               |
| $\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t}  = \vec{\mathbf{0}}$                                                          | curl of $\vec{\mathbf{E}}$ is proportional to the rate of change of $\vec{\mathbf{B}}$ |
| $\nabla \times \vec{\mathbf{B}} -\, \frac1c\, \frac{\partial\vec{\mathbf{E}}}{\partial t} = \frac{4\pi}{c}\vec{\mathbf{j}}    \nabla \cdot \vec{\mathbf{E}} = 4 \pi \rho$ | _wha?_                                                                                 |

## Image Lazy Loading

You can enable lazy loading for each image added via markdown by setting `lazyLoading` to `true` in your config file:

```js
export default {
  markdown: {
    image: {
      // image lazy loading is disabled by default
      lazyLoading: true
    }
  }
}
```

## Advanced Configuration

VitePress uses [markdown-it](https://github.com/markdown-it/markdown-it) as the Markdown renderer. A lot of the extensions above are implemented via custom plugins. You can further customize the `markdown-it` instance using the `markdown` option in `.vitepress/config.js`:

```js
import { defineConfig } from 'vitepress'
import markdownItAnchor from 'markdown-it-anchor'
import markdownItFoo from 'markdown-it-foo'

export default defineConfig({
  markdown: {
    // options for markdown-it-anchor
    // https://github.com/valeriangalliat/markdown-it-anchor#usage
    anchor: {
      permalink: markdownItAnchor.permalink.headerLink()
    },

    // options for @mdit-vue/plugin-toc
    // https://github.com/mdit-vue/mdit-vue/tree/main/packages/plugin-toc#options
    toc: { level: [1, 2] },

    config: (md) => {
      // use more markdown-it plugins!
      md.use(markdownItFoo)
    }
  }
})
```

See full list of configurable properties in [Config Reference: App Config](../reference/site-config#markdown).