> For the complete documentation index, see [llms.txt](https://docs.vale.sh/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vale.sh/formats/mdx.md).
# MDX
Learn how Vale handles MDX content.
{% hint style="info" %}
Vale v3.18.0 or later parses [MDX](https://mdxjs.com/) natively. Earlier versions require the external program [`mdx2vast`](https://github.com/jdkato/mdx2vast) (`npm install -g mdx2vast`) on your `$PATH`.
{% endhint %}
The supported extension is `.mdx`.
MDX is Markdown plus ESM statements, JSX elements, and JavaScript expressions. The JavaScript holds no prose, and Vale treats it as code and ignores it:
* JSX tags, their attributes, and self-closing elements (``).
* ESM `import` and `export` statements, including multiline bodies.
* JavaScript expressions—inline (`{Math.PI * 2}`) and standing on their own.
* Fenced blocks: Blocks surrounded by three or more backticks.
* Code spans: Text surrounded by backticks.
Because MDX removed indented code blocks from the grammar, four leading spaces are an ordinary paragraph and its prose is linted.
## [JSX children](#jsx-children)
{% hint style="info" %}
Requires Vale v3.19.0 or later. Earlier versions skipped a JSX element entirely, children included.
{% endhint %}
A JSX element's *children* are Markdown, just as MDX itself reads them, so the prose inside `...` or `` is linted:
```mdx
```
The children carry the element's name as a [class scope](/topics/scopes.md#class-scopes), so a rule can target one component's content (`scope: text.class.Aside`), and a component whose content shouldn't be linted can be excluded by name:
```ini
IgnoredClasses = RawOutput
```
The same applies inline: in `HTML is a language`, the word "HTML" is linted as part of its sentence.
One exception: an element opened *and* closed on a single standalone line (`inner` as its own block) is read as code.
## [The MDX package](#the-mdx-package)
{% hint style="info" %}
This package exists for versions before v3.18.0, whose parser threw on inline expressions that aren't valid JavaScript—ending the run rather than the file. The native parser reads them without complaint.
{% endhint %}
The [`MDX`](https://github.com/vale-cli/MDX) package carries the configuration for those cases:
```ini
Packages = MDX
```
See [`Packages`](/keys/packages.md) for more information.
## [Comments](#comments)
Vale supports comment-based configuration in MDX files:
* Turn Vale off entirely:
```mdx
{/* vale off */}
This text will be ignored.
{/* vale on */}
```
* Turn off a specific rule:
```mdx
{/* vale Style.Redundancy = NO */}
This is some text ACT test
{/* vale Style.Redundancy = YES */}
```
* Turn off specific match(es) within a rule:
```mdx
{/* vale Style.Redundancy["ACT test","OTHER"] = NO */}
This is some text ACT test
{/* vale Style.Redundancy["ACT test","OTHER"] = YES */}
```
* Turn on or off specific styles:
```mdx
{/* vale StyleName1 = YES */}
{/* vale StyleName2 = NO */}
```
* Set styles (enabling them and switching off any other styles):
```mdx
{/* vale style = StyleName1 */}
{/* vale styles = StyleName1, StyleName2 */}
```
---
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## Querying This Documentation
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```
GET https://docs.vale.sh/formats/mdx.md?ask=&goal=
```
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