mdast-util-mdx

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[mdast][] extensions to parse and serialize [MDX][]: ESM, JSX, and expressions.

Contents

* What is this?
* When to use this
* Install
* Use
* API
* mdxFromMarkdown()
* mdxToMarkdown(options?)
* ToMarkdownOptions
* HTML
* Syntax
* Syntax tree
* Types
* Compatibility
* Related
* Contribute
* License

What is this?

This package contains two extensions that add support for MDX syntax in
markdown to [mdast][]: ESM (import x from 'y'), JSX (), and
expressions ({Math.PI}).
These extensions plug into
[mdast-util-from-markdown][mdast-util-from-markdown] (to support parsing
MDX in markdown into a syntax tree) and
[mdast-util-to-markdown][mdast-util-to-markdown] (to support serializing
MDX in syntax trees to markdown).

When to use this

You can use these extensions when you are working with
mdast-util-from-markdown and mdast-util-to-markdown already.

When working with mdast-util-from-markdown, you must combine this package
with [micromark-extension-mdx][mdx] or [micromark-extension-mdxjs][mdxjs].

Instead of this package, you can also use the extensions separately:

* mdast-util-mdx-expression
— support MDX expressions
* mdast-util-mdx-jsx
— support MDX JSX
* mdast-util-mdxjs-esm
— support MDX ESM

All these packages are used in [remark-mdx][remark-mdx], which
focusses on making it easier to transform content by abstracting these
internals away.

Install

This package is [ESM only][esm].
In Node.js (version 16+), install with [npm][]:

``sh
npm install mdast-util-mdx
`

In Deno with [esm.sh][esmsh]:

`js
import {mdxFromMarkdown, mdxToMarkdown} from 'https://esm.sh/mdast-util-mdx@3'
`

In browsers with [esm.sh][esmsh]:

`html

`

Use

Say our document example.mdx contains:

`mdx
import Box from "place"

Here’s an expression:

{
1 + 1 / } /
}

Which you can also put inline: {1+1}.



- Lists, which can be indented.


`

…and our module example.js looks as follows:

`js
import fs from 'node:fs/promises'
import {mdxjs} from 'micromark-extension-mdxjs'
import {fromMarkdown} from 'mdast-util-from-markdown'
import {mdxFromMarkdown, mdxToMarkdown} from 'mdast-util-mdx'
import {toMarkdown} from 'mdast-util-to-markdown'

const doc = await fs.readFile('example.mdx')

const tree = fromMarkdown(doc, {
extensions: [mdxjs()],
mdastExtensions: [mdxFromMarkdown()]
})

console.log(tree)

const out = toMarkdown(tree, {extensions: [mdxToMarkdown()]})

console.log(out)
`

…now running node example.js yields (positional info removed for brevity):

`js
{
type: 'root',
children: [
{
type: 'mdxjsEsm',
value: 'import Box from "place"',
data: {
estree: {
type: 'Program',
body: [
{
type: 'ImportDeclaration',
specifiers: [
{
type: 'ImportDefaultSpecifier',
local: {type: 'Identifier', name: 'Box'}
}
],
source: {type: 'Literal', value: 'place', raw: '"place"'}
}
],
sourceType: 'module'
}
}
},
{
type: 'paragraph',
children: [{type: 'text', value: 'Here’s an expression:'}]
},
{
type: 'mdxFlowExpression',
value: '\n1 + 1 / } /\n',
data: {
estree: {
type: 'Program',
body: [
{
type: 'ExpressionStatement',
expression: {
type: 'BinaryExpression',
left: {type: 'Literal', value: 1, raw: '1'},
operator: '+',
right: {type: 'Literal', value: 1, raw: '1'}
}
}
],
sourceType: 'module'
}
}
},
{
type: 'paragraph',
children: [
{type: 'text', value: 'Which you can also put inline: '},
{
type: 'mdxTextExpression',
value: '1+1',
data: {
estree: {
type: 'Program',
body: [
{
type: 'ExpressionStatement',
expression: {
type: 'BinaryExpression',
left: {type: 'Literal', value: 1, raw: '1'},
operator: '+',
right: {type: 'Literal', value: 1, raw: '1'}
}
}
],
sourceType: 'module'
}
}
},
{type: 'text', value: '.'}
]
},
{
type: 'mdxJsxFlowElement',
name: 'Box',
attributes: [],
children: [
{
type: 'mdxJsxFlowElement',
name: 'SmallerBox',
attributes: [],
children: [
{
type: 'list',
ordered: false,
start: null,
spread: false,
children: [
{
type: 'listItem',
spread: false,
checked: null,
children: [
{
type: 'paragraph',
children: [
{type: 'text', value: 'Lists, which can be indented.'}
]
}
]
}
]
}
]
}
]
}
]
}
`

`mdx
import Box from "place"

Here’s an expression:

{
1 + 1 / } /
}

Which you can also put inline: {1+1}.



* Lists, which can be indented.


`

API

This package exports the identifiers [mdxFromMarkdown][api-mdx-from-markdown]
and [mdxToMarkdown][api-mdx-to-markdown].
There is no default export.

$3

Create an extension for [mdast-util-from-markdown][mdast-util-from-markdown]
to enable MDX (ESM, JSX, expressions).

###### Returns

Extension for mdast-util-from-markdown to enable MDX
([FromMarkdownExtension][from-markdown-extension]).

When using the [syntax extensions with addResult][mdxjs], ESM and expression
nodes will have data.estree fields set to ESTree [Program][program] node.

$3

Create an extension for [mdast-util-to-markdown][mdast-util-to-markdown]
to enable MDX (ESM, JSX, expressions).

Extension for [mdast-util-to-markdown][mdast-util-to-markdown].

###### Parameters

* options ([ToMarkdownOptions][api-to-markdown-options])
— configuration

###### Returns

Extension for mdast-util-to-markdown to enable MDX
([FromMarkdownExtension][to-markdown-extension]).

$3

Configuration (TypeScript type).

###### Fields

* quote ('"' or "'", default: '"')
— preferred quote to use around attribute values
* quoteSmart (boolean, default: false)
— use the other quote if that results in less bytes
* tightSelfClosing (boolean, default: false)
— do not use an extra space when closing self-closing elements:
instead of
* printWidth (number, default: Infinity)
— try and wrap syntax at this width.
When set to a finite number (say, 80), the formatter will print
attributes on separate lines when a tag doesn’t fit on one line.
The normal behavior is to print attributes with spaces between them instead
of line endings

HTML

MDX has no representation in HTML.
Though, when you are dealing with MDX, you will likely go through hast.
You can enable passing MDX through to hast by configuring
[mdast-util-to-hast][mdast-util-to-hast] with passThrough: ['mdxjsEsm',
'mdxFlowExpression', 'mdxJsxFlowElement', 'mdxJsxTextElement', 'mdxTextExpression'].

Syntax

See [Syntax in micromark-extension-mdxjs][mdxjs].

Syntax tree

This utility combines several mdast utilities.
See their readmes for the node types supported in the tree:

* mdast-util-mdx-expression
— support MDX expressions
* mdast-util-mdx-jsx
— support MDX JSX
* mdast-util-mdxjs-esm
— support MDX ESM

Types

This package is fully typed with [TypeScript][].
It exports the additional types
MdxFlowExpression and MdxTextExpression
from mdast-util-mdx-expression;
MdxJsxAttribute,
MdxJsxAttributeValueExpression,
MdxJsxExpressionAttribute,
MdxJsxFlowElement,
MdxJsxTextElement,
and [ToMarkdownOptions][api-to-markdown-options]
from mdast-util-mdx-jsx;
and MdxjsEsm from mdast-util-mdxjs-esm.

It also registers the node types with @types/mdast and @types/hast.
If you’re working with the syntax tree, make sure to import this utility
somewhere in your types, as that registers the new node types in the tree.

`js
/**
* @typedef {import('mdast-util-mdx')}
*/

import {visit} from 'unist-util-visit'

/* @type {import('mdast').Root} /
const tree = getMdastNodeSomeHow()

visit(tree, function (node) {
// node can now be an expression, JSX, or ESM node.
})
`

Compatibility

Projects maintained by the unified collective are compatible with maintained
versions of Node.js.

When we cut a new major release, we drop support for unmaintained versions of
Node.
This means we try to keep the current release line, mdast-util-mdx@^3,
compatible with Node.js 16.

This utility works with mdast-util-from-markdown version 2+ and
mdast-util-to-markdown version 2+.

Related

* [remark-mdx][remark-mdx]
— remark plugin to support MDX
* [micromark-extension-mdx][mdx]
— micromark extension to parse MDX
* [micromark-extension-mdxjs][mdxjs]
— micromark extension to parse JavaScript-aware MDX

Contribute

See [contributing.md][contributing] in [syntax-tree/.github][health] for
ways to get started.
See [support.md`][support] for ways to get help.

This project has a [code of conduct][coc].
By interacting with this repository, organization, or community you agree to
abide by its terms.

License

[MIT][license] © [Titus Wormer][author]

[build-badge]: https://github.com/syntax-tree/mdast-util-mdx/workflows/main/badge.svg

[build]: https://github.com/syntax-tree/mdast-util-mdx/actions

[coverage-badge]: https://img.shields.io/codecov/c/github/syntax-tree/mdast-util-mdx.svg

[coverage]: https://codecov.io/github/syntax-tree/mdast-util-mdx

[downloads-badge]: https://img.shields.io/npm/dm/mdast-util-mdx.svg

[downloads]: https://www.npmjs.com/package/mdast-util-mdx

[size-badge]: https://img.shields.io/badge/dynamic/json?label=minzipped%20size&query=$.size.compressedSize&url=https://deno.bundlejs.com/?q=mdast-util-mdx

[size]: https://bundlejs.com/?q=mdast-util-mdx

[sponsors-badge]: https://opencollective.com/unified/sponsors/badge.svg

[backers-badge]: https://opencollective.com/unified/backers/badge.svg

[collective]: https://opencollective.com/unified

[chat-badge]: https://img.shields.io/badge/chat-discussions-success.svg

[chat]: https://github.com/syntax-tree/unist/discussions

[npm]: https://docs.npmjs.com/cli/install

[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c

[esmsh]: https://esm.sh

[typescript]: https://www.typescriptlang.org

[license]: license

[author]: https://wooorm.com

[health]: https://github.com/syntax-tree/.github

[contributing]: https://github.com/syntax-tree/.github/blob/main/contributing.md

[support]: https://github.com/syntax-tree/.github/blob/main/support.md

[coc]: https://github.com/syntax-tree/.github/blob/main/code-of-conduct.md

[mdast]: https://github.com/syntax-tree/mdast

[mdast-util-from-markdown]: https://github.com/syntax-tree/mdast-util-from-markdown

[from-markdown-extension]: https://github.com/syntax-tree/mdast-util-from-markdown#extension

[mdast-util-to-markdown]: https://github.com/syntax-tree/mdast-util-to-markdown

[to-markdown-extension]: https://github.com/syntax-tree/mdast-util-to-markdown#options

[mdast-util-to-hast]: https://github.com/syntax-tree/mdast-util-to-hast

[mdx]: https://github.com/micromark/micromark-extension-mdx

[mdxjs]: https://github.com/micromark/micromark-extension-mdxjs

[remark-mdx]: https://github.com/mdx-js/mdx/tree/next/packages/remark-mdx

[program]: https://github.com/estree/estree/blob/master/es2015.md#programs

[api-mdx-from-markdown]: #mdxfrommarkdown

[api-mdx-to-markdown]: #mdxtomarkdownoptions

[api-to-markdown-options]: #tomarkdownoptions