Add support for GFM footnotes

Author: wooorm

index.js

@@ -9,6 +9,10 @@ import {
   gfmAutolinkLiteralFromMarkdown,
   gfmAutolinkLiteralToMarkdown
 } from 'mdast-util-gfm-autolink-literal'
+import {
+  gfmFootnoteFromMarkdown,
+  gfmFootnoteToMarkdown
+} from 'mdast-util-gfm-footnote'
 import {
   gfmStrikethroughFromMarkdown,
   gfmStrikethroughToMarkdown
@@ -25,6 +29,7 @@ import {
 export function gfmFromMarkdown() {
   return [
     gfmAutolinkLiteralFromMarkdown,
+    gfmFootnoteFromMarkdown(),
     gfmStrikethroughFromMarkdown,
     gfmTableFromMarkdown,
     gfmTaskListItemFromMarkdown
@@ -39,6 +44,7 @@ export function gfmToMarkdown(options) {
   return {
     extensions: [
       gfmAutolinkLiteralToMarkdown,
+      gfmFootnoteToMarkdown(),
       gfmStrikethroughToMarkdown,
       gfmTableToMarkdown(options),
       gfmTaskListItemToMarkdown

package.json

@@ -40,6 +40,7 @@
   ],
   "dependencies": {
     "mdast-util-gfm-autolink-literal": "^1.0.0",
+    "mdast-util-gfm-footnote": "^1.0.0",
     "mdast-util-gfm-strikethrough": "^1.0.0",
     "mdast-util-gfm-table": "^1.0.0",
     "mdast-util-gfm-task-list-item": "^1.0.0"

readme.md

@@ -25,6 +25,8 @@ Alternatively, the extensions can be used separately:
 
 *   [`syntax-tree/mdast-util-gfm-autolink-literal`](https://github.com/syntax-tree/mdast-util-gfm-autolink-literal)
     — support GFM autolink literals
+*   [`syntax-tree/mdast-util-gfm-footnote`](https://github.com/syntax-tree/mdast-util-gfm-footnote)
+    — support GFM footnotes
 *   [`syntax-tree/mdast-util-gfm-strikethrough`](https://github.com/syntax-tree/mdast-util-gfm-strikethrough)
     — support GFM strikethrough
 *   [`syntax-tree/mdast-util-gfm-table`](https://github.com/syntax-tree/mdast-util-gfm-table)
@@ -54,6 +56,12 @@ Say we have the following file, `example.md`:
 
 www.example.com, https://example.com, and contact@example.com.
 
+## Footnote
+
+A note[^1]
+
+[^1]: Big note.
+
 ## Strikethrough
 
 ~one~ or ~~two~~ tildes.
@@ -130,6 +138,22 @@ Now, running `node example` yields:
         {type: 'text', value: '.'}
       ]
     },
+    {type: 'heading', depth: 2, children: [{type: 'text', value: 'Footnote'}]},
+    {
+      type: 'paragraph',
+      children: [
+        {type: 'text', value: 'A note'},
+        {type: 'footnoteReference', identifier: '1', label: '1'}
+      ]
+    },
+    {
+      type: 'footnoteDefinition',
+      identifier: '1',
+      label: '1',
+      children: [
+        {type: 'paragraph', children: [{type: 'text', value: 'Big note.'}]}
+      ]
+    },
     {
       type: 'heading',
       depth: 2,
@@ -202,6 +226,12 @@ Now, running `node example` yields:
 
 [www.example.com](http://www.example.com), <https://example.com>, and <contact@example.com>.
 
+## Footnote
+
+A note[^1]
+
+[^1]: Big note.
+
 ## Strikethrough
 
 ~~one~~ or ~~two~~ tildes.