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# mdast-util-from-markdown
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**[mdast][]** utility that turns markdown into a syntax tree.
## Contents
* [What is this?](#what-is-this)
* [When should I use this?](#when-should-i-use-this)
* [Install](#install)
* [Use](#use)
* [API](#api)
* [`fromMarkdown(value[, encoding][, options])`](#frommarkdownvalue-encoding-options)
* [`CompileContext`](#compilecontext)
* [`CompileData`](#compiledata)
* [`Encoding`](#encoding)
* [`Extension`](#extension)
* [`Handle`](#handle)
* [`OnEnterError`](#onentererror)
* [`OnExitError`](#onexiterror)
* [`Options`](#options)
* [`Token`](#token)
* [`Transform`](#transform)
* [`Value`](#value)
* [List of extensions](#list-of-extensions)
* [Syntax](#syntax)
* [Syntax tree](#syntax-tree)
* [Types](#types)
* [Compatibility](#compatibility)
* [Security](#security)
* [Related](#related)
* [Contribute](#contribute)
* [License](#license)
## What is this?
This package is a utility that takes markdown input and turns it into an
[mdast][] syntax tree.
This utility uses [`micromark`][micromark], which turns markdown into tokens,
and then turns those tokens into nodes.
This package is used inside [`remark-parse`][remark-parse], which focusses on
making it easier to transform content by abstracting these internals away.
## When should I use this?
If you want to handle syntax trees manually, use this.
When you *just* want to turn markdown into HTML, use [`micromark`][micromark]
instead.
For an easier time processing content, use the **[remark][]** ecosystem instead.
You can combine this package with other packages to add syntax extensions to
markdown.
Notable examples that deeply integrate with this package are
[`mdast-util-gfm`][mdast-util-gfm],
[`mdast-util-mdx`][mdast-util-mdx],
[`mdast-util-frontmatter`][mdast-util-frontmatter],
[`mdast-util-math`][mdast-util-math], and
[`mdast-util-directive`][mdast-util-directive].
## Install
This package is [ESM only][esm].
In Node.js (version 16+), install with [npm][]:
```sh
npm install mdast-util-from-markdown
```
In Deno with [`esm.sh`][esmsh]:
```js
import {fromMarkdown} from 'https://esm.sh/mdast-util-from-markdown@2'
```
In browsers with [`esm.sh`][esmsh]:
```html
<script type="module">
import {fromMarkdown} from 'https://esm.sh/mdast-util-from-markdown@2?bundle'
</script>
```
## Use
Say we have the following markdown file `example.md`:
```markdown
## Hello, *World*!
```
…and our module `example.js` looks as follows:
```js
import fs from 'node:fs/promises'
import {fromMarkdown} from 'mdast-util-from-markdown'
const doc = await fs.readFile('example.md')
const tree = fromMarkdown(doc)
console.log(tree)
```
…now running `node example.js` yields (positional info removed for brevity):
```js
{
type: 'root',
children: [
{
type: 'heading',
depth: 2,
children: [
{type: 'text', value: 'Hello, '},
{type: 'emphasis', children: [{type: 'text', value: 'World'}]},
{type: 'text', value: '!'}
]
}
]
}
```
## API
This package exports the identifier [`fromMarkdown`][api-from-markdown].
There is no default export.
The export map supports the [`development` condition][development].
Run `node --conditions development example.js` to get instrumented dev code.
Without this condition, production code is loaded.
### `fromMarkdown(value[, encoding][, options])`
Turn markdown into a syntax tree.
###### Overloads
* `(value: Value, encoding: Encoding, options?: Options) => Root`
* `(value: Value, options?: Options) => Root`
###### Parameters
* `value` ([`Value`][api-value])
— markdown to parse
* `encoding` ([`Encoding`][api-encoding], default: `'utf8'`)
— [character encoding][encoding] for when `value` is
[`Uint8Array`][uint8-array]
* `options` ([`Options`][api-options], optional)
— configuration
###### Returns
mdast tree ([`Root`][root]).
### `CompileContext`
mdast compiler context (TypeScript type).
###### Fields
* `stack` ([`Array<Node>`][node])
— stack of nodes
* `tokenStack` (`Array<[Token, OnEnterError | undefined]>`)
— stack of tokens
* `data` ([`CompileData`][api-compile-data])
— info passed around; key/value store
* `buffer` (`() => undefined`)
— capture some of the output data
* `resume` (`() => string`)
— stop capturing and access the output data
* `enter` (`(node: Node, token: Token, onError?: OnEnterError) => undefined`)
— enter a node
* `exit` (`(token: Token, onError?: OnExitError) => undefined`)
— exit a node
* `sliceSerialize` (`(token: Token, expandTabs?: boolean) => string`)
— get the string value of a token
* `config` (`Required<Extension>`)
— configuration
### `CompileData`
Interface of tracked data (TypeScript type).
###### Type
```ts
interface CompileData { /* see code */ }
```
When working on extensions that use more data, extend the corresponding
interface to register their types:
```ts
declare module 'mdast-util-from-markdown' {
interface CompileData {
// Register a new field.
mathFlowInside?: boolean | undefined
}
}
```
### `Encoding`
Encodings supported by the [`Uint8Array`][uint8-array] class (TypeScript type).
See [`micromark`][micromark-api] for more info.
###### Type
```ts
type Encoding = 'utf8' | /* … */
```
### `Extension`
Change how markdown tokens from micromark are turned into mdast (TypeScript
type).
###### Properties
* `canContainEols` (`Array<string>`, optional)
— token types where line endings are used
* `enter` ([`Record<string, Handle>`][api-handle], optional)
— opening handles
* `exit` ([`Record<string, Handle>`][api-handle], optional)
— closing handles
* `transforms` ([`Array<Transform>`][api-transform], optional)
— tree transforms
### `Handle`
Handle a token (TypeScript type).
###### Parameters
* `this` ([`CompileContext`][api-compile-context])
— context
* `token` ([`Token`][api-token])
— current token
###### Returns
Nothing (`undefined`).
### `OnEnterError`
Handle the case where the `right` token is open, but it is closed (by the
`left` token) or because we reached the end of the document (TypeScript type).
###### Parameters
* `this` ([`CompileContext`][api-compile-context])
— context
* `left` ([`Token`][api-token] or `undefined`)
— left token
* `right` ([`Token`][api-token])
— right token
###### Returns
Nothing (`undefined`).
### `OnExitError`
Handle the case where the `right` token is open but it is closed by
exiting the `left` token (TypeScript type).
###### Parameters
* `this` ([`CompileContext`][api-compile-context])
— context
* `left` ([`Token`][api-token])
— left token
* `right` ([`Token`][api-token])
— right token
###### Returns
Nothing (`undefined`).
### `Options`
Configuration (TypeScript type).
###### Properties
* `extensions` ([`Array<MicromarkExtension>`][micromark-extension], optional)
— micromark extensions to change how markdown is parsed
* `mdastExtensions` ([`Array<Extension | Array<Extension>>`][api-extension],
optional)
— extensions for this utility to change how tokens are turned into a tree
### `Token`
Token from micromark (TypeScript type).
###### Type
```ts
type Token = { /* … */ }
```
### `Transform`
Extra transform, to change the AST afterwards (TypeScript type).
###### Parameters
* `tree` ([`Root`][root])
— tree to transform
###### Returns
New tree ([`Root`][root]) or nothing (in which case the current tree is used).
### `Value`
Contents of the file (TypeScript type).
See [`micromark`][micromark-api] for more info.
###### Type
```ts
type Value = Uint8Array | string
```
## List of extensions
* [`syntax-tree/mdast-util-directive`](https://github.com/syntax-tree/mdast-util-directive)
— directives
* [`syntax-tree/mdast-util-frontmatter`](https://github.com/syntax-tree/mdast-util-frontmatter)
— frontmatter (YAML, TOML, more)
* [`syntax-tree/mdast-util-gfm`](https://github.com/syntax-tree/mdast-util-gfm)
— GFM
* [`syntax-tree/mdast-util-gfm-autolink-literal`](https://github.com/syntax-tree/mdast-util-gfm-autolink-literal)
— GFM autolink literals
* [`syntax-tree/mdast-util-gfm-footnote`](https://github.com/syntax-tree/mdast-util-gfm-footnote)
— GFM footnotes
* [`syntax-tree/mdast-util-gfm-strikethrough`](https://github.com/syntax-tree/mdast-util-gfm-strikethrough)
— GFM strikethrough
* [`syntax-tree/mdast-util-gfm-table`](https://github.com/syntax-tree/mdast-util-gfm-table)
— GFM tables
* [`syntax-tree/mdast-util-gfm-task-list-item`](https://github.com/syntax-tree/mdast-util-gfm-task-list-item)
— GFM task list items
* [`syntax-tree/mdast-util-math`](https://github.com/syntax-tree/mdast-util-math)
— math
* [`syntax-tree/mdast-util-mdx`](https://github.com/syntax-tree/mdast-util-mdx)
— MDX
* [`syntax-tree/mdast-util-mdx-expression`](https://github.com/syntax-tree/mdast-util-mdx-expression)
— MDX expressions
* [`syntax-tree/mdast-util-mdx-jsx`](https://github.com/syntax-tree/mdast-util-mdx-jsx)
— MDX JSX
* [`syntax-tree/mdast-util-mdxjs-esm`](https://github.com/syntax-tree/mdast-util-mdxjs-esm)
— MDX ESM
## Syntax
Markdown is parsed according to CommonMark.
Extensions can add support for other syntax.
If youre interested in extending markdown,
[more information is available in micromarks readme][micromark-extension].
## Syntax tree
The syntax tree is [mdast][].
## Types
This package is fully typed with [TypeScript][].
It exports the additional types [`CompileContext`][api-compile-context],
[`CompileData`][api-compile-data],
[`Encoding`][api-encoding],
[`Extension`][api-extension],
[`Handle`][api-handle],
[`OnEnterError`][api-on-enter-error],
[`OnExitError`][api-on-exit-error],
[`Options`][api-options],
[`Token`][api-token],
[`Transform`][api-transform], and
[`Value`][api-value].
## 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-from-markdown@^2`, compatible with Node.js 16.
## Security
As markdown is sometimes used for HTML, and improper use of HTML can open you up
to a [cross-site scripting (XSS)][xss] attack, use of `mdast-util-from-markdown`
can also be unsafe.
When going to HTML, use this utility in combination with
[`hast-util-sanitize`][hast-util-sanitize] to make the tree safe.
## Related
* [`syntax-tree/mdast-util-to-markdown`](https://github.com/syntax-tree/mdast-util-to-markdown)
— serialize mdast as markdown
* [`micromark/micromark`](https://github.com/micromark/micromark)
— parse markdown
* [`remarkjs/remark`](https://github.com/remarkjs/remark)
— process markdown
## 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]
<!-- Definitions -->
[build-badge]: https://github.com/syntax-tree/mdast-util-from-markdown/workflows/main/badge.svg
[build]: https://github.com/syntax-tree/mdast-util-from-markdown/actions
[coverage-badge]: https://img.shields.io/codecov/c/github/syntax-tree/mdast-util-from-markdown.svg
[coverage]: https://codecov.io/github/syntax-tree/mdast-util-from-markdown
[downloads-badge]: https://img.shields.io/npm/dm/mdast-util-from-markdown.svg
[downloads]: https://www.npmjs.com/package/mdast-util-from-markdown
[size-badge]: https://img.shields.io/badge/dynamic/json?label=minzipped%20size&query=$.size.compressedSize&url=https://deno.bundlejs.com/?q=mdast-util-from-markdown
[size]: https://bundlejs.com/?q=mdast-util-from-markdown
[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
[esmsh]: https://esm.sh
[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
[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
[typescript]: https://www.typescriptlang.org
[mdast]: https://github.com/syntax-tree/mdast
[node]: https://github.com/syntax-tree/mdast#nodes
[mdast-util-gfm]: https://github.com/syntax-tree/mdast-util-gfm
[mdast-util-mdx]: https://github.com/syntax-tree/mdast-util-mdx
[mdast-util-frontmatter]: https://github.com/syntax-tree/mdast-util-frontmatter
[mdast-util-math]: https://github.com/syntax-tree/mdast-util-math
[mdast-util-directive]: https://github.com/syntax-tree/mdast-util-directive
[root]: https://github.com/syntax-tree/mdast#root
[uint8-array]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
[encoding]: https://nodejs.org/api/util.html#whatwg-supported-encodings
[xss]: https://en.wikipedia.org/wiki/Cross-site_scripting
[hast-util-sanitize]: https://github.com/syntax-tree/hast-util-sanitize
[micromark]: https://github.com/micromark/micromark
[micromark-api]: https://github.com/micromark/micromark/tree/main/packages/micromark#micromarkvalue-encoding-options
[micromark-extension]: https://github.com/micromark/micromark#extensions
[remark]: https://github.com/remarkjs/remark
[remark-parse]: https://github.com/remarkjs/remark/tree/main/packages/remark-parse
[development]: https://nodejs.org/api/packages.html#packages_resolving_user_conditions
[api-from-markdown]: #frommarkdownvalue-encoding-options
[api-compile-context]: #compilecontext
[api-compile-data]: #compiledata
[api-encoding]: #encoding
[api-extension]: #extension
[api-handle]: #handle
[api-on-enter-error]: #onentererror
[api-on-exit-error]: #onexiterror
[api-options]: #options
[api-token]: #token
[api-transform]: #transform
[api-value]: #value