mdast-util-directive

What is mdast-util-directive?

The `mdast-util-directive` package is a utility for working with directives in Markdown Abstract Syntax Trees (MDAST). It allows you to parse, transform, and stringify custom directives in Markdown documents, enabling more advanced and customizable Markdown processing.

What are mdast-util-directive's main functionalities?

Parsing Directives

This feature allows you to parse custom directives in Markdown content into an MDAST. The code sample demonstrates how to set up a processor with `remark-parse` and `mdast-util-directive` to parse a custom directive.

const { fromMarkdown } = require('mdast-util-directive');
const { unified } = require('unified');
const markdown = require('remark-parse');

const processor = unified()
  .use(markdown)
  .use(fromMarkdown);

const mdContent = ':::{.example}
This is a custom directive
:::';

const tree = processor.parse(mdContent);
console.log(tree);

Transforming Directives

This feature allows you to transform custom directives in the MDAST. The code sample shows how to use `unist-util-visit` to visit and transform a custom directive node in the syntax tree.

const { visit } = require('unist-util-visit');
const { fromMarkdown } = require('mdast-util-directive');
const { unified } = require('unified');
const markdown = require('remark-parse');

const processor = unified()
  .use(markdown)
  .use(fromMarkdown);

const mdContent = ':::{.example}
This is a custom directive
:::';

const tree = processor.parse(mdContent);

visit(tree, 'containerDirective', (node) => {
  node.data = { hName: 'div', hProperties: { className: 'example' } };
});

console.log(tree);

Stringifying Directives

This feature allows you to stringify custom directives back into Markdown. The code sample demonstrates how to set up a processor to parse and then stringify a custom directive.

const { toMarkdown } = require('mdast-util-directive');
const { unified } = require('unified');
const markdown = require('remark-parse');
const stringify = require('remark-stringify');

const processor = unified()
  .use(markdown)
  .use(fromMarkdown)
  .use(stringify)
  .use(toMarkdown);

const mdContent = ':::{.example}
This is a custom directive
:::';

const tree = processor.parse(mdContent);
const output = processor.stringify(tree);
console.log(output);

Other packages similar to mdast-util-directive

remark-directive

The `remark-directive` package is a plugin for `remark` that provides support for parsing and transforming directives in Markdown. It is similar to `mdast-util-directive` but is specifically designed to work within the `remark` ecosystem, providing a more integrated experience for users of `remark`.

remark-custom-blocks

The `remark-custom-blocks` package allows you to define custom block-level elements in Markdown. It is similar to `mdast-util-directive` in that it provides a way to extend Markdown with custom syntax, but it focuses specifically on block-level elements and their transformations.

remark-shortcodes

The `remark-shortcodes` package enables the use of shortcode syntax in Markdown documents. It is similar to `mdast-util-directive` in that it allows for custom syntax extensions, but it uses a different approach with shortcode-like syntax rather than directive syntax.

README

mdast-util-directive

mdast extensions to parse and serialize generic directives proposal (:cite[smith04], ::youtube[Video of a cat in a box]{v=01ab2cd3efg}, and such).

Contents

• What is this?
• When to use this
• Install
• Use
• API
  • directiveFromMarkdown
  • directiveToMarkdown
• Syntax tree
  • Nodes
  • Mixin
  • Directive
• Types
• Compatibility
• Related
• Contribute
• License

What is this?

This package contains extensions that add support for generic directives to mdast-util-from-markdown and mdast-util-to-markdown.

This package handles the syntax tree. You can use this with some more code to match your specific needs, to allow for anything from callouts, citations, styled blocks, forms, embeds, spoilers, etc. Traverse the tree to change directives to whatever you please.

When to use this

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

Directives are one of the four ways to extend markdown: an arbitrary extension syntax (see Extending markdown in micromark’s docs for the alternatives and more info). This mechanism works well when you control the content: who authors it, what tools handle it, and where it’s displayed. When authors can read a guide on how to embed a tweet but are not expected to know the ins and outs of HTML or JavaScript. Directives don’t work well if you don’t know who authors content, what tools handle it, and where it ends up. Example use cases are a docs website for a project or product, or blogging tools and static site generators.

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

This utility does not handle how directives are turned to HTML. You must traverse the tree to change directives to whatever you please.

Install

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

npm install mdast-util-directive

In Deno with esm.sh:

import {directiveFromMarkdown, directiveToMarkdown} from 'https://esm.sh/mdast-util-directive@2'

In browsers with esm.sh:

<script type="module">
  import {directiveFromMarkdown, directiveToMarkdown} from 'https://esm.sh/mdast-util-directive@2?bundle'
</script>

Use

Say our document example.md contains:

A lovely language know as :abbr[HTML]{title="HyperText Markup Language"}.

…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 {directive} from 'micromark-extension-directive'
import {directiveFromMarkdown, directiveToMarkdown} from 'mdast-util-directive'

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

const tree = fromMarkdown(doc, {
  extensions: [directive()],
  mdastExtensions: [directiveFromMarkdown]
})

console.log(tree)

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

console.log(out)

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

{
  type: 'root',
  children: [
    {
      type: 'paragraph',
      children: [
        {type: 'text', value: 'A lovely language know as '},
        {
          type: 'textDirective',
          name: 'abbr',
          attributes: {title: 'HyperText Markup Language'},
          children: [{type: 'text', value: 'HTML'}]
        },
        {type: 'text', value: '.'}
      ]
    }
  ]
}

A lovely language know as :abbr[HTML]{title="HyperText Markup Language"}.

API

This package exports the identifiers directiveFromMarkdown and directiveToMarkdown. There is no default export.

directiveFromMarkdown

Extension for mdast-util-from-markdown.

directiveToMarkdown

Extension for mdast-util-to-markdown.

There are no options, but passing options.quote to mdast-util-to-markdown is honored for attributes.

Syntax tree

The following interfaces are added to mdast by this utility.

Nodes

TextDirective

interface TextDirective <: Parent {
  type: 'textDirective'
  children: [PhrasingContent]
}

TextDirective includes Directive

TextDirective (Parent) is a directive. It can be used where phrasing content is expected. Its content model is also phrasing content. It includes the mixin Directive.

For example, the following Markdown:

:name[Label]{#x.y.z key=value}

Yields:

{
  type: 'textDirective',
  name: 'name',
  attributes: {id: 'x', class: 'y z', key: 'value'},
  children: [{type: 'text', value: 'Label'}]
}

LeafDirective

interface LeafDirective <: Parent {
  type: 'leafDirective'
  children: [PhrasingContent]
}

LeafDirective includes Directive

LeafDirective (Parent) is a directive. It can be used where flow content is expected. Its content model is phrasing content. It includes the mixin Directive.

For example, the following Markdown:

::youtube[Label]{v=123}

Yields:

{
  type: 'leafDirective',
  name: 'youtube',
  attributes: {v: '123'},
  children: [{type: 'text', value: 'Label'}]
}

ContainerDirective

interface ContainerDirective <: Parent {
  type: 'containerDirective'
  children: [FlowContent]
}

ContainerDirective includes Directive

ContainerDirective (Parent) is a directive. It can be used where flow content is expected. Its content model is also flow content. It includes the mixin Directive.

The phrasing in the label is, when available, added as a paragraph with a directiveLabel: true field, as the head of its content.

For example, the following Markdown:

:::spoiler[Open at your own peril]
He dies.
:::

Yields:

{
  type: 'containerDirective',
  name: 'spoiler',
  attributes: {},
  children: [
    {
      type: 'paragraph',
      data: {directiveLabel: true},
      children: [{type: 'text', value: 'Open at your own peril'}]
    },
    {
      type: 'paragraph',
      children: [{type: 'text', value: 'He dies.'}]
    }
  ]
}

Mixin

Directive

interface mixin Directive {
  name: string
  attributes: Attributes?
}

interface Attributes {}
typedef string AttributeName
typedef string AttributeValue

Directive represents something defined by an extension.

The name field must be present and represents an identifier of an extension.

The attributes field represents information associated with the node. The value of the attributes field implements the Attributes interface.

In the Attributes interface, every field must be an AttributeName and every value an AttributeValue. The fields and values can be anything: there are no semantics (such as by HTML or hast).

In JSON, the value null must be treated as if the attribute was not included. In JavaScript, both null and undefined must be similarly ignored.

Types

This package is fully typed with TypeScript. It exports the additional types ContainerDirective, LeafDirective, TextDirective, and Directive.

It also registers the node types with @types/mdast. If you’re working with the syntax tree, make sure to import this utility somewhere in your types, as that registers the new node types in the tree.

/**
 * @typedef {import('mdast-util-directive')}
 */

import {visit} from 'unist-util-visit'

/** @type {import('mdast').Root} */
const tree = getMdastNodeSomeHow()

visit(tree, (node) => {
  // `node` can now be one of the nodes for directives.
})

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+.

Related

• remarkjs/remark-directive — remark plugin to support generic directives
• micromark/micromark-extension-directive — micromark extension to parse directives

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