unified

Project: syntax-tree/mdast-util-gfm-footnote

Package: mdast-util-gfm-footnote@1.0.1

  1. Dependents: 0
  2. mdast extension to parse and serialize GFM footnotes
  1. util 147
  2. markdown 145
  3. utility 143
  4. unist 133
  5. mdast 90
  6. mdast-util 31
  7. gfm 20
  8. markup 19
  9. footnote 7
  10. note 5

mdast-util-gfm-footnote

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mdast extensions to parse and serialize GFM footnotes.

Contents

What is this?

This package contains extensions that add support for the footnote syntax enabled by GFM to mdast-util-from-markdown and mdast-util-to-markdown.

GFM footnotes were announced September 30, 2021 but are not specified. Their implementation on github.com is currently buggy. The bugs have been reported on cmark-gfm.

When to use this

These tools are all rather low-level. In most cases, you’d want to use remark-gfm with remark instead.

When you are working with syntax trees and want all of GFM, use mdast-util-gfm instead.

When working with mdast-util-from-markdown, you must combine this package with micromark-extension-gfm-footnote.

This utility does not handle how markdown is turned to HTML. That’s done by mdast-util-to-hast. If your content is not in English, you should configure that utility.

Install

This package is ESM only. In Node.js (version 12.20+, 14.14+, or 16.0+), install with npm:

npm install mdast-util-gfm-footnote

In Deno with esm.sh:

import {gfmFootnoteFromMarkdown, gfmFootnoteToMarkdown} from 'https://esm.sh/mdast-util-gfm-footnote@1'

In browsers with esm.sh:

<script type="module">
  import {gfmFootnoteFromMarkdown, gfmFootnoteToMarkdown} from 'https://esm.sh/mdast-util-gfm-footnote@1?bundle'
</script>

Use

Say our document example.md contains:

Hi![^1]

[^1]: big note

…and our module example.js looks as follows:

import fs from 'node:fs/promises'
import {fromMarkdown} from 'mdast-util-from-markdown'
import {toMarkdown} from 'mdast-util-to-markdown'
import {gfmFootnote} from 'micromark-extension-gfm-footnote'
import {gfmFootnoteFromMarkdown, gfmFootnoteToMarkdown} from 'mdast-util-gfm-footnote'

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

const tree = fromMarkdown(doc, {
  extensions: [gfmFootnote()],
  mdastExtensions: [gfmFootnoteFromMarkdown()]
})

console.log(tree)

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

console.log(out)

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

{
  type: 'root',
  children: [
    {
      type: 'paragraph',
      children: [
        {type: 'text', value: 'Hi!'},
        {type: 'footnoteReference', identifier: '1', label: '1'}
      ]
    },
    {
      type: 'footnoteDefinition',
      identifier: '1',
      label: '1',
      children: [
        {type: 'paragraph', children: [{type: 'text', value: 'big note'}]}
      ]
    }
  ]
}
Hi\![^1]

[^1]: big note

API

This package exports the identifiers gfmFootnoteFromMarkdown and gfmFootnoteToMarkdown. There is no default export.

gfmFootnoteFromMarkdown()

Function that can be called to get an extension for mdast-util-from-markdown.

gfmFootnoteToMarkdown()

Function that can be called to get an extension for mdast-util-to-markdown.

Syntax tree

The following interfaces are added to mdast by this utility.

Nodes

FootnoteDefinition

interface FootnoteDefinition <: Parent {
  type: "footnoteDefinition"
  children: [FlowContent]
}

FootnoteDefinition includes Association

FootnoteDefinition (Parent) represents content relating to the document that is outside its flow.

FootnoteDefinition can be used where flow content is expected. Its content model is also flow content.

FootnoteDefinition includes the mixin Association.

FootnoteDefinition should be associated with FootnoteReferences.

For example, the following markdown:

[^alpha]: bravo and charlie.

Yields:

{
  type: 'footnoteDefinition',
  identifier: 'alpha',
  label: 'alpha',
  children: [{
    type: 'paragraph',
    children: [{type: 'text', value: 'bravo and charlie.'}]
  }]
}

FootnoteReference

interface FootnoteReference <: Node {
  type: "footnoteReference"
}

FootnoteReference includes Association

FootnoteReference (Node) represents a marker through association.

FootnoteReference can be used where static phrasing content is expected. It has no content model.

FootnoteReference includes the mixin Association.

FootnoteReference should be associated with a FootnoteDefinition.

For example, the following markdown:

[^alpha]

Yields:

{
  type: 'footnoteReference',
  identifier: 'alpha',
  label: 'alpha'
}

Content model

FlowContent (GFM footnotes)

type FlowContentGfm = FootnoteDefinition | FlowContent

StaticPhrasingContent (GFM footnotes)

type StaticPhrasingContentGfm =
  FootnoteReference | StaticPhrasingContent

Types

This package is fully typed with TypeScript. It does not export additional types.

The FootnoteDefinition and FootnoteReference node types are supported in @types/mdast by default.

Compatibility

Projects maintained by the unified collective are compatible with all maintained versions of Node.js. As of now, that is Node.js 12.20+, 14.14+, and 16.0+. Our projects sometimes work with older versions, but this is not guaranteed.

This plugin works with mdast-util-from-markdown version 1+ and mdast-util-to-markdown version 1+.

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