mdast extension to parse and serialize GFM footnotes
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[mdast][] extensions to parse and serialize [GFM][] footnotes.
* What is this?
* When to use this
* Install
* Use
* API
* gfmFootnoteFromMarkdown()
* gfmFootnoteToMarkdown(options?)
* ToMarkdownOptions
* HTML
* Syntax
* Syntax tree
* Nodes
* Content model
* Types
* Compatibility
* Related
* Contribute
* License
This package contains two extensions that add support for GFM footnote syntax
in markdown to [mdast][].
These extensions plug into
[mdast-util-from-markdown][mdast-util-from-markdown] (to support parsing
footnotes in markdown into a syntax tree) and
[mdast-util-to-markdown][mdast-util-to-markdown] (to support serializing
footnotes in syntax trees to markdown).
GFM footnotes were [announced September 30, 2021][post] but are not specified.
Their implementation on github.com is currently buggy.
The bugs have been reported on [cmark-gfm][cmark-gfm].
You can use these extensions when you are working withmdast-util-from-markdown and mdast-util-to-markdown already.
When working with mdast-util-from-markdown, you must combine this package
with [micromark-extension-gfm-footnote][micromark-extension-gfm-footnote].
When you don’t need a syntax tree, you can use [micromark][micromark]
directly with micromark-extension-gfm-footnote.
When you are working with syntax trees and want all of GFM, use
[mdast-util-gfm][mdast-util-gfm] instead.
All these packages are used [remark-gfm][remark-gfm], which
focusses on making it easier to transform content by abstracting these
internals away.
This utility does not handle how markdown is turned to HTML.
That’s done by [mdast-util-to-hast][mdast-util-to-hast].
If your content is not in English, you should configure that utility.
This package is [ESM only][esm].
In Node.js (version 16+), install with [npm][]:
``sh`
npm install mdast-util-gfm-footnote
In Deno with [esm.sh][esmsh]:
`js`
import {gfmFootnoteFromMarkdown, gfmFootnoteToMarkdown} from 'https://esm.sh/mdast-util-gfm-footnote@2'
In browsers with [esm.sh][esmsh]:
`html`
Say our document example.md contains:
`markdown
In the Solar System, Mercury[^mercury] and Venus[^venus] have very small tilts.
[^mercury]:
Mercury is the first planet from the Sun and the smallest
in the Solar System.
[^venus]:
Venus is the second planet from
the Sun.
`
…and our module example.js looks as follows:
`js
import fs from 'node:fs/promises'
import {fromMarkdown} from 'mdast-util-from-markdown'
import {
gfmFootnoteFromMarkdown,
gfmFootnoteToMarkdown
} from 'mdast-util-gfm-footnote'
import {toMarkdown} from 'mdast-util-to-markdown'
import {gfmFootnote} from 'micromark-extension-gfm-footnote'
const value = await fs.readFile('example.md', 'utf8')
const tree = fromMarkdown(value, {
extensions: [gfmFootnote()],
mdastExtensions: [gfmFootnoteFromMarkdown()]
})
console.log(tree)
const result = toMarkdown(tree, {
extensions: [gfmFootnoteToMarkdown({firstLineBlank: true})]
})
console.log(result)
`
…now running node example.js yields (positional info removed for brevity):
`js`
{
type: 'root',
children: [
{
type: 'paragraph',
children: [
{type: 'text', value: 'In the Solar System, Mercury'},
{type: 'footnoteReference', identifier: 'mercury', label: 'mercury'},
{type: 'text', value: ' and Venus'},
{type: 'footnoteReference', identifier: 'venus', label: 'venus'},
{type: 'text', value: ' have very small tilts.'}
]
},
{
type: 'footnoteDefinition',
identifier: 'mercury',
label: 'mercury',
children: [
{
type: 'paragraph',
children: [
{type: 'strong', children: [{type: 'text', value: 'Mercury'}]},
{
type: 'text',
value:
' is the first planet from the Sun and the smallest\n' +
'in the Solar System.'
}
]
}
]
},
{
type: 'footnoteDefinition',
identifier: 'venus',
label: 'venus',
children: [
{
type: 'paragraph',
children: [
{type: 'strong', children: [{type: 'text', value: 'Venus'}]},
{type: 'text', value: ' is the second planet from\nthe Sun.'}
]
}
]
}
]
}
`markdown
In the Solar System, Mercury[^mercury] and Venus[^venus] have very small tilts.
[^mercury]:
Mercury is the first planet from the Sun and the smallest
in the Solar System.
[^venus]:
Venus is the second planet from
the Sun.
`
This package exports the identifiers
[gfmFootnoteFromMarkdown][api-gfmfootnotefrommarkdown] andgfmFootnoteToMarkdown
[][api-gfmfootnotetomarkdown].ToMarkdownOptions
There is no default export.
It exports the type [][api-to-markdown-options].
Create an extension for
[mdast-util-from-markdown][mdast-util-from-markdown]
to enable GFM footnotes in markdown.
###### Returns
Extension for mdast-util-from-markdown
([][frommarkdownextension]).
Create an extension for
[mdast-util-to-markdown][mdast-util-to-markdown]
to enable GFM footnotes in markdown.
###### Parameters
* options ([ToMarkdownOptions][api-to-markdown-options], optional)
— configuration
###### Returns
Extension for mdast-util-to-markdown
([][tomarkdownextension]).
Configuration (TypeScript type).
###### Fields
* firstLineBlank (boolean, default: false)
— use a blank line for the first line of footnote definitions
This utility does not handle how markdown is turned to HTML.
That’s done by [mdast-util-to-hast][mdast-util-to-hast].
If your content is not in English, you should configure that utility.
See [Syntax in micromark-extension-gfm-footnote][syntax].
The following interfaces are added to [mdast][] by this utility.
#### FootnoteDefinition
`idl
interface FootnoteDefinition <: Parent {
type: 'footnoteDefinition'
children: [FlowContent]
}
FootnoteDefinition includes Association
`
FootnoteDefinition ([Parent][dfn-parent]) represents content relating
to the document that is outside its flow.
FootnoteDefinition can be used where [flow][dfn-flow-content] content
is expected.
Its content model is also [flow][dfn-flow-content] content.
FootnoteDefinition includes the mixin
[Association][dfn-mxn-association].
FootnoteDefinition should be associated with
[FootnoteReferences][dfn-footnote-reference].
For example, the following markdown:
`markdown`
[^alpha]: bravo and charlie.
Yields:
`js`
{
type: 'footnoteDefinition',
identifier: 'alpha',
label: 'alpha',
children: [{
type: 'paragraph',
children: [{type: 'text', value: 'bravo and charlie.'}]
}]
}
#### FootnoteReference
`idl
interface FootnoteReference <: Node {
type: 'footnoteReference'
}
FootnoteReference includes Association
`
FootnoteReference ([Node][dfn-node]) represents a marker through
association.
FootnoteReference can be used where
[phrasing][dfn-phrasing-content] content is expected.
It has no content model.
FootnoteReference includes the mixin [Association][dfn-mxn-association].
FootnoteReference should be associated with a
[FootnoteDefinition][dfn-footnote-definition].
For example, the following markdown:
`markdown`
[^alpha]
Yields:
`js`
{
type: 'footnoteReference',
identifier: 'alpha',
label: 'alpha'
}
#### FlowContent (GFM footnotes)
`idl`
type FlowContentGfm = FootnoteDefinition | FlowContent
#### PhrasingContent (GFM footnotes)
`idl`
type PhrasingContentGfm = FootnoteReference | PhrasingContent
This package is fully typed with [TypeScript][].
It does not export additional types.
The FootnoteDefinition and FootnoteReference types of the mdast nodes are@types/mdast
exposed from .
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-gfm-footnote@^2, compatible with Node.js 16.
* [remark-gfm][remark-gfm]mdast-util-gfm
— remark plugin to support GFM
* [][mdast-util-gfm]micromark-extension-gfm-footnote
— same but all of GFM (autolink literals, footnotes, strikethrough, tables,
tasklists)
* [][micromark-extension-gfm-footnote]
— micromark extension to parse GFM footnotes
See [contributing.md][contributing] in [syntax-tree/.github][health] forsupport.md`][support] for ways to get help.
ways to get started.
See [
This project has a [code of conduct][coc].
By interacting with this repository, organization, or community you agree to
abide by its terms.
[MIT][license] © [Titus Wormer][author]
[api-gfmfootnotefrommarkdown]: #gfmfootnotefrommarkdown
[api-gfmfootnotetomarkdown]: #gfmfootnotetomarkdownoptions
[api-to-markdown-options]: #tomarkdownoptions
[author]: https://wooorm.com
[backers-badge]: https://opencollective.com/unified/backers/badge.svg
[build]: https://github.com/syntax-tree/mdast-util-gfm-footnote/actions
[build-badge]: https://github.com/syntax-tree/mdast-util-gfm-footnote/workflows/main/badge.svg
[chat]: https://github.com/syntax-tree/unist/discussions
[chat-badge]: https://img.shields.io/badge/chat-discussions-success.svg
[cmark-gfm]: https://github.com/github/cmark-gfm
[coc]: https://github.com/syntax-tree/.github/blob/main/code-of-conduct.md
[collective]: https://opencollective.com/unified
[contributing]: https://github.com/syntax-tree/.github/blob/main/contributing.md
[coverage]: https://codecov.io/github/syntax-tree/mdast-util-gfm-footnote
[coverage-badge]: https://img.shields.io/codecov/c/github/syntax-tree/mdast-util-gfm-footnote.svg
[dfn-flow-content]: #flowcontent-gfm-footnotes
[dfn-footnote-definition]: #footnotedefinition
[dfn-footnote-reference]: #footnotereference
[dfn-mxn-association]: https://github.com/syntax-tree/mdast#association
[dfn-node]: https://github.com/syntax-tree/unist#node
[dfn-parent]: https://github.com/syntax-tree/mdast#parent
[dfn-phrasing-content]: #phrasingcontent-gfm-footnotes
[downloads]: https://www.npmjs.com/package/mdast-util-gfm-footnote
[downloads-badge]: https://img.shields.io/npm/dm/mdast-util-gfm-footnote.svg
[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
[esmsh]: https://esm.sh
[frommarkdownextension]: https://github.com/syntax-tree/mdast-util-from-markdown#extension
[gfm]: https://github.github.com/gfm/
[health]: https://github.com/syntax-tree/.github
[license]: license
[mdast]: https://github.com/syntax-tree/mdast
[mdast-util-from-markdown]: https://github.com/syntax-tree/mdast-util-from-markdown
[mdast-util-gfm]: https://github.com/syntax-tree/mdast-util-gfm
[mdast-util-to-hast]: https://github.com/syntax-tree/mdast-util-to-hast
[mdast-util-to-markdown]: https://github.com/syntax-tree/mdast-util-to-markdown
[micromark]: https://github.com/micromark/micromark
[micromark-extension-gfm-footnote]: https://github.com/micromark/micromark-extension-gfm-footnote
[npm]: https://docs.npmjs.com/cli/install
[post]: https://github.blog/changelog/2021-09-30-footnotes-now-supported-in-markdown-fields/
[remark-gfm]: https://github.com/remarkjs/remark-gfm
[size]: https://bundlejs.com/?q=mdast-util-gfm-footnote
[size-badge]: https://img.shields.io/badge/dynamic/json?label=minzipped%20size&query=$.size.compressedSize&url=https://deno.bundlejs.com/?q=mdast-util-gfm-footnote
[sponsors-badge]: https://opencollective.com/unified/sponsors/badge.svg
[support]: https://github.com/syntax-tree/.github/blob/main/support.md
[syntax]: https://github.com/micromark/micromark-extension-gfm-footnote#syntax
[tomarkdownextension]: https://github.com/syntax-tree/mdast-util-to-markdown#options
[typescript]: https://www.typescriptlang.org