What is mdast-util-from-markdown?
The mdast-util-from-markdown package is a utility to parse Markdown and convert it into a Markdown Abstract Syntax Tree (MDAST). It allows developers to work with the tree structure to manipulate, inspect, or transform Markdown content programmatically.
What are mdast-util-from-markdown's main functionalities?
Parsing Markdown to MDAST
This feature allows you to parse a Markdown string and produce an MDAST. The MDAST can then be manipulated or inspected as needed.
import { fromMarkdown } from 'mdast-util-from-markdown';
const mdast = fromMarkdown('# Hello world');
Using plugins to extend parsing capabilities
This feature enables the use of plugins to extend the parsing capabilities of the utility. For example, using the 'micromark-extension-gfm' plugin to support GitHub Flavored Markdown (GFM) features like task lists.
import { fromMarkdown } from 'mdast-util-from-markdown';
import gfm from 'micromark-extension-gfm';
const mdast = fromMarkdown('# Hello world\n\n- [ ] task list item', {extensions: [gfm()]});
Other packages similar to mdast-util-from-markdown
remark-parse
Remark-parse is a plugin for the remark processor that parses Markdown into an MDAST. It is part of the unified ecosystem and is similar to mdast-util-from-markdown but is typically used as part of the remark ecosystem.
markdown-it
Markdown-it is a Markdown parser with a focus on speed and extensibility. It can be used to parse Markdown into a syntax tree, which is similar to MDAST but with its own structure. It differs from mdast-util-from-markdown in that it is a full parser and renderer, not just a utility for producing an AST.
marked
Marked is a Markdown parser and compiler that is designed for speed. It produces an abstract syntax tree that can be used similarly to MDAST, but it is not directly compatible with the unified ecosystem like mdast-util-from-markdown is.
mdast-util-from-markdown

mdast utility that turns markdown into a syntax tree.
Contents
What is this?
This package is a utility that takes markdown input and turns it into an
mdast syntax tree.
This utility uses micromark
, which turns markdown into tokens,
and then turns those tokens into nodes.
This package is used inside 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
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-mdx
,
mdast-util-frontmatter
,
mdast-util-math
, and
mdast-util-directive
.
Install
This package is ESM only.
In Node.js (version 14.14+ and 16.0+), install with npm:
npm install mdast-util-from-markdown
In Deno with esm.sh
:
import {fromMarkdown} from 'https://esm.sh/mdast-util-from-markdown@1'
In browsers with esm.sh
:
<script type="module">
import {fromMarkdown} from 'https://esm.sh/mdast-util-from-markdown@1?bundle'
</script>
Use
Say we have the following markdown file example.md
:
## Hello, *World*!
…and our module example.js
looks as follows:
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):
{
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
.
There is no default export.
The export map supports the development
condition.
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
Returns
mdast tree (Root
).
CompileContext
mdast compiler context (TypeScript type).
Fields
stack
(Array<Node>
)
— stack of nodes
tokenStack
(Array<[Token, OnEnterError | undefined]>
)
— stack of tokens
getData
((key: string) => unknown
)
— get data from the key/value store (see CompileData
)
setData
((key: string, value?: unknown) => void
)
— set data into the key/value store (see CompileData
)
buffer
(() => void
)
— capture some of the output data
resume
(() => string
)
— stop capturing and access the output data
enter
((node: Node, token: Token, onError?: OnEnterError) => Node
)
— enter a token
exit
((token: Token, onError?: OnExitError) => Node
)
— exit a token
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
interface CompileData { }
When working on extensions that use more data, extend the corresponding
interface to register their types:
declare module 'mdast-util-from-markdown' {
interface CompileData {
mathFlowInside?: boolean | undefined
}
}
Encoding
Encodings supported by the Buffer
class (TypeScript type).
See micromark
for more info.
Type
type Encoding = 'utf8' |
Extension
Change how markdown tokens from micromark are turned into mdast (TypeScript
type).
Properties
Handle
Handle a token (TypeScript type).
Parameters
Returns
Nothing (void
).
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
Returns
Nothing (void
).
OnExitError
Handle the case where the right
token is open but it is closed by
exiting the left
token (TypeScript type).
Parameters
Returns
Nothing (void
).
Options
Configuration (TypeScript type).
Properties
Token
Token from micromark (TypeScript type).
See micromark
for more info.
Type
type Token = { }
Transform
Extra transform, to change the AST afterwards (TypeScript type).
Parameters
tree
(Root
)
— tree to transform
Returns
New tree (Root
) or nothing (in which case the current tree is used).
Value
Contents of the file (TypeScript type).
See micromark
for more info.
Type
type Value = string | Uint8Array
List of extensions
Syntax
Markdown is parsed according to CommonMark.
Extensions can add support for other syntax.
If you’re interested in extending markdown,
more information is available in micromark’s readme.
Syntax tree
The syntax tree is mdast.
Types
This package is fully typed with TypeScript.
It exports the additional types CompileContext
,
CompileData
,
Encoding
,
Extension
,
Handle
,
OnEnterError
,
OnExitError
,
Options
,
Token
,
Transform
, and
Value
.
Compatibility
Projects maintained by the unified collective are compatible with all maintained
versions of Node.js.
As of now, that is Node.js 14.14+ and 16.0+.
Our projects sometimes work with older versions, but this is not guaranteed.
Security
As markdown is sometimes used for HTML, and improper use of HTML can open you up
to a cross-site scripting (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
to make the tree safe.
Related
Contribute
See contributing.md
in syntax-tree/.github
for
ways to get started.
See support.md
for ways to get help.
This project has a code of conduct.
By interacting with this repository, organization, or community you agree to
abide by its terms.
License
MIT © Titus Wormer