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vitepress/docs/en/guide/markdown.md

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# 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 link 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()]
}
```
It uses [`postcss-prefix-selector`](https://github.com/RadValentin/postcss-prefix-selector) under the hood. You can pass its options like this:
```js
postcssIsolateStyles({
includeFiles: [/vp-doc\.css/] // defaults to /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**
10 months ago
<<< @/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 `@`, it will act as the source root. By default, it's 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
# Docs
## Basics
<!--@include: ./parts/basics.md{3,}-->
```
**Part file** (`parts/basics.md`)
```md
Some getting started stuff.
### Configuration
Can be created using `.foorc.json`.
```
**Equivalent code**
```md
# 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
# Docs
## Basics
<!--@include: ./parts/basics.md#basic-usage{,2}-->
<!--@include: ./parts/basics.md#basic-usage{5,}-->
```
**Part file** (`parts/basics.md`)
```md
<!-- #region basic-usage -->
## Usage Line 1
## Usage Line 2
## Usage Line 3
<!-- #endregion basic-usage -->
```
**Equivalent code**
```md
# 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.
:::
## 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).