micromark
v4.0.0
Published
small commonmark compliant markdown parser with positional info and concrete tokens
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Readme
micromark
Markdown parser.
Note: this is the
micromark
package from the micromark monorepo. See the monorepo readme for more on the project. See this readme for how to use it.
Feature highlights
- [x] compliant (100% to CommonMark)
- [x] extensions (100% GFM, 100% MDX.js, directives, frontmatter, math)
- [x] safe (by default)
- [x] robust (±2k tests, 100% coverage, fuzz testing)
- [x] small (smallest CM parser at ±14kb)
Contents
When should I use this?
- If you just want to turn markdown into HTML (with maybe a few extensions)
- If you want to do really complex things with markdown
See § Comparison for more info
What is this?
micromark
is an open source markdown parser written in JavaScript.
It’s implemented as a state machine that emits concrete tokens, so that every
byte is accounted for, with positional info.
It then compiles those tokens directly to HTML, but other tools can take the
data and for example build an AST which is easier to work with
(mdast-util-to-markdown
).
While most markdown parsers work towards compliancy with CommonMark (or GFM),
this project goes further by following how the reference parsers (cmark
,
cmark-gfm
) work, which is confirmed with thousands of extra tests.
Other than CommonMark and GFM, micromark also supports common extensions to markdown such as MDX, math, and frontmatter.
These npm packages have a sibling project in Rust:
markdown-rs
.
- to learn markdown, see this cheatsheet and tutorial
- for more about us, see
unifiedjs.com
- for updates, see Twitter
- for questions, see Discussions
- to help, see contribute and sponsor below
Install
This package is ESM only. In Node.js (version 16+), install with npm:
npm install micromark
In Deno with esm.sh
:
import {micromark} from 'https://esm.sh/micromark@3'
In browsers with esm.sh
:
<script type="module">
import {micromark} from 'https://esm.sh/micromark@3?bundle'
</script>
Use
Typical use (buffering):
import {micromark} from 'micromark'
console.log(micromark('## Hello, *world*!'))
Yields:
<h2>Hello, <em>world</em>!</h2>
You can pass extensions (in this case micromark-extension-gfm
):
import {micromark} from 'micromark'
import {gfm, gfmHtml} from 'micromark-extension-gfm'
const value = '* [x] [email protected] ~~strikethrough~~'
const result = micromark(value, {
extensions: [gfm()],
htmlExtensions: [gfmHtml()]
})
console.log(result)
Yields:
<ul>
<li><input checked="" disabled="" type="checkbox"> <a href="mailto:[email protected]">[email protected]</a> <del>strikethrough</del></li>
</ul>
Streaming interface:
import {createReadStream} from 'node:fs'
import {stream} from 'micromark/stream'
createReadStream('example.md')
.on('error', handleError)
.pipe(stream())
.pipe(process.stdout)
function handleError(error) {
// Handle your error here!
throw error
}
API
micromark
core has two entries in its export map: micromark
and
micromark/stream
.
micromark
exports the identifier micromark
.
micromark/stream
exports the identifier stream
.
There are no default exports.
The export map supports the development
condition.
Run node --conditions development module.js
to get instrumented dev code.
Without this condition, production code is loaded.
See § Size & debug for more info.
micromark(value[, encoding][, options])
Compile markdown to HTML.
Note: which encodings are supported depends on the engine. For info on Node.js, see WHATWG supported encodings.
Parameters
value
(string
orUint8Array
) — markdown to parseencoding
(string
, default:'utf8'
) — character encoding to understandvalue
as when it’s aUint8Array
options
(Options
, optional) — configuration
Returns
Compiled HTML (string
).
stream(options?)
Create a duplex (readable and writable) stream.
Some of the work to parse markdown can be done streaming, but in the end buffering is required.
micromark does not handle errors for you, so you must handle errors on whatever
streams you pipe into it.
As markdown does not know errors, micromark
itself does not emit errors.
Parameters
options
(Options
, optional) — configuration
Returns
Duplex stream.
Options
Configuration (TypeScript type).
Fields
allowDangerousHtml
Whether to allow (dangerous) HTML (boolean
, default: false
).
The default is false
, which still parses the HTML according to CommonMark
but shows the HTML as text instead of as elements.
Pass true
for trusted content to get actual HTML elements.
See § Security.
allowDangerousProtocol
Whether to allow dangerous protocols in links and images (boolean
, default:
false
).
The default is false
, which drops URLs in links and images that use dangerous
protocols.
Pass true
for trusted content to support all protocols.
URLs that have no protocol (which means it’s relative to the current page, such
as ./some/page.html
) and URLs that have a safe protocol (for images: http
,
https
; for links: http
, https
, irc
, ircs
, mailto
, xmpp
), are
safe.
All other URLs are dangerous and dropped.
See § Security.
defaultLineEnding
Default line ending to use when compiling to HTML, for line endings not in
value
('\r'
, '\n'
, or '\r\n'
; default: first line ending or '\n'
).
Generally, micromark
copies line endings (\r
, \n
, \r\n
) in the markdown
document over to the compiled HTML.
In some cases, such as > a
, CommonMark requires that extra line endings are
added: <blockquote>\n<p>a</p>\n</blockquote>
.
To create that line ending, the document is checked for the first line ending
that is used.
If there is no line ending, defaultLineEnding
is used.
If that isn’t configured, \n
is used.
extensions
Array of syntax extensions (Array<SyntaxExtension>
, default: []
).
See § Extensions.
htmlExtensions
Array of syntax extensions (Array<HtmlExtension>
, default: []
).
See § Extensions.
Types
This package is fully typed with TypeScript.
It exports the additional type Options
.
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, micromark@^4
, compatible
with Node.js 16.
Security
This package is safe.
See security.md
in micromark/.github
for how to
submit a security report.
Contribute
See contributing.md
in micromark/.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, organisation, or community you agree to abide by its terms.
Sponsor
Support this effort and give back by sponsoring on OpenCollective!