Alexandro.Net

Version 1.0.0

@stackline/remark-frontmatter

remark plugin to support frontmatter (yaml, toml, and more)

Independent maintenance of remark-frontmatter 4.0.1. Original authors and licenses are retained.

Installation

# Preserve existing imports with an npm alias
npm install remark-frontmatter@npm:@stackline/remark-frontmatter@1.0.0
# Or use the scoped package name in your imports
npm install @stackline/remark-frontmatter@1.0.0

Node.js: See compatibility notes. Read the compatibility and maintenance notes before migrating.

Usage and API

The reference below may retain upstream package names. Use the alias installation above to run those imports with this Stackline release.

@stackline/remark-frontmatter

Independent maintenance fork of remark-frontmatter@4.0.1, preserving its API and published type declarations.

npm install @stackline/remark-frontmatter
# Keep existing imports:
npm install remark-frontmatter@npm:@stackline/remark-frontmatter@1.0.0

Stackline · Issues · Community

See UPSTREAM.md for source identity and issue review, and CHANGELOG.md for maintenance changes. Functional tests also run against the final npm tarball; releases are published from GitHub Actions with provenance.

Upstream documentation

remark-frontmatter

Build Coverage Downloads Size Sponsors Backers Chat

remark plugin to support frontmatter (YAML, TOML, and more).

Contents

What is this?

This package is a unified (remark) plugin to add support for YAML, TOML, and other frontmatter. You can use this to add support for parsing and serializing this syntax extension.

unified is an AST (abstract syntax tree) based transform project. remark is everything unified that relates to markdown. The layer under remark is called mdast, which is only concerned with syntax trees. Another layer underneath is micromark, which is only concerned with parsing. This package is a small wrapper to integrate all of these.

When should I use this?

Frontmatter is a metadata format in front of content. It’s typically written in YAML and is often used with markdown. This mechanism works well when you want authors, that have some markup experience, to configure where or how the content is displayed or supply metadata about content. Frontmatter does not work everywhere so it makes markdown less portable. A good example use case is markdown being rendered by (static) site generators.

Install

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

npm install remark-frontmatter

In Deno with Skypack:

import remarkFrontmatter from 'https://cdn.skypack.dev/remark-frontmatter@4?dts'

In browsers with Skypack:

<script type="module">
  import remarkFrontmatter from 'https://cdn.skypack.dev/remark-frontmatter@4?min'
</script>

Use

Say we have the following file, example.md:

+++
title = "New Website"
+++

# Other markdown

And our module, example.js, looks as follows:

import {read} from 'to-vfile'
import {unified} from 'unified'
import remarkParse from 'remark-parse'
import remarkFrontmatter from 'remark-frontmatter'
import remarkStringify from 'remark-stringify'

main()

async function main() {
  const file = await unified()
    .use(remarkParse)
    .use(remarkStringify)
    .use(remarkFrontmatter, ['yaml', 'toml'])
    .use(() => (tree) => {
      console.dir(tree)
    })
    .process(await read('example.md'))

  console.log(String(file))
}

Now, running node example yields:

{
  type: 'root',
  children: [
    {type: 'toml', value: 'title = "New Website"', position: [Object]},
    {type: 'heading', depth: 1, children: [Array], position: [Object]}
  ],
  position: {
    start: {line: 1, column: 1, offset: 0},
    end: {line: 6, column: 1, offset: 48}
  }
}

+++
title = "New Website"
+++

# Other markdown

API

This package exports no identifiers. The default export is remarkFrontmatter.

unified().use(remarkFrontmatter[, options])

Configures remark so that it can parse and serialize frontmatter (YAML, TOML, and more). Doesn’t parse the data inside them: create your own plugin to do that.

options

One preset or Matter, or an array of them, defining all the supported frontmatters (default: 'yaml').

preset

Either 'yaml' or 'toml':

Matter

An object with a type and either a marker or a fence:

Examples

Example: custom marker

A custom frontmatter with different open and close markers, repeated 3 times, that looks like this:

<<<
data
>>>

# hi

…can be supported with:

// …
.use(remarkFrontmatter, {type: 'custom', marker: {open: '<', close: '>'}})
// …

Example: custom fence

A custom frontmatter with custom fences that are not repeated like this:

{
  "key": "value"
}

# hi

…can be supported with:

// …
.use(remarkFrontmatter, {type: 'json', fence: {open: '{', close: '}'}})
// …

Syntax

This plugin applies a micromark extensions to parse the syntax. See its readme for how it works:

The syntax supported depends on the given configuration.

Syntax tree

This plugin applies one mdast utility to build and serialize the AST. See its readme for how it works:

The node types supported in the tree depend on the given configuration.

Types

This package is fully typed with TypeScript. The YAML node type is supported in @types/mdast by default. To add other node types, register them by adding them to FrontmatterContentMap:

import type {Literal} from 'mdast'

interface TOML extends Literal {
  type: 'toml'
}

declare module 'mdast' {
  interface FrontmatterContentMap {
    // Allow using toml nodes defined by `remark-frontmatter`.
    toml: TOML
  }
}

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 unified 6+ and remark 13+.

Security

Use of remark-frontmatter does not involve rehype (hast) or user content so there are no openings for cross-site scripting (XSS) attacks.

Related

Contribute

See contributing.md in remarkjs/.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

Upstream issues and maintenance review

Upstream and maintenance review

Independent maintenance of remark-frontmatter@4.0.1 as @stackline/remark-frontmatter.

Issue triage

The bounded open-issue query returned no issue entries. This is not evidence that the upstream is abandoned or bug-free. No upstream runtime bug fix is claimed.

Historical snapshots were checked against an independently installed exact original npm package before refresh. All fixtures retain differential AST and serialization checks against that original package.

The evidence query fetched the latest 100 open and 30 closed issue/PR entries and removed PRs. This is a bounded review, not a claim of exhaustive issue history or resolution of every issue.

Release verification

GitHub Actions publishes the reviewed passing-CI tarball. Release completion requires exact source identity, zero open CodeQL alerts, npm provenance and tarball identity, normal and aliased installs, and matching immutable GitHub release assets. Existing versions are never replaced.

Release changes

Changelog

1.0.0

Release files and references

Package bytes, npm provenance and the immutable GitHub release were verified for this version. Security checks describe the reviewed release; documented compatibility risks and upstream reports are not blanket claims of resolution.