remark-lint-first-heading-level

remark-lint rule to warn when the first heading has an unexpected rank.

Contents

• What is this?
• When should I use this?
• Presets
• Install
• Use
• API
  • unified().use(remarkLintFirstHeadingLevel[, options])
  • Options
• Recommendation
• Examples
• Compatibility
• Contribute
• License

What is this?

This package checks the rank of the first heading.

When should I use this?

You can use this package to check that the rank of first headings is consistent.

Presets

This plugin is not included in presets maintained here.

Install

This package is ESM only. In Node.js (version 16+), install with npm:

npm install remark-lint-first-heading-level

In Deno with esm.sh:

import remarkLintFirstHeadingLevel from 'https://esm.sh/remark-lint-first-heading-level@4'

In browsers with esm.sh:

<script type="module">
  import remarkLintFirstHeadingLevel from 'https://esm.sh/remark-lint-first-heading-level@4?bundle'
</script>

Use

On the API:

import remarkLint from 'remark-lint'
import remarkLintFirstHeadingLevel from 'remark-lint-first-heading-level'
import remarkParse from 'remark-parse'
import remarkStringify from 'remark-stringify'
import {read} from 'to-vfile'
import {unified} from 'unified'
import {reporter} from 'vfile-reporter'

const file = await read('example.md')

await unified()
  .use(remarkParse)
  .use(remarkLint)
  .use(remarkLintFirstHeadingLevel)
  .use(remarkStringify)
  .process(file)

console.error(reporter(file))

On the CLI:

remark --frail --use remark-lint --use remark-lint-first-heading-level .

On the CLI in a config file (here a package.json):

 …
 "remarkConfig": {
   "plugins": [
     …
     "remark-lint",
+    "remark-lint-first-heading-level",
     …
   ]
 }
 …

API

This package exports no identifiers. It exports the TypeScript type Options. The default export is remarkLintFirstHeadingLevel.

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

Warn when the first heading has an unexpected rank.

Parameters

• options (Options, default: 1) — configuration

Returns

Transform (Transformer from unified).

Options

Configuration (TypeScript type).

Type

type Options = 1 | 2 | 3 | 4 | 5 | 6

Recommendation

In most cases you’d want to first heading in a markdown document to start at rank 1. In some cases a different rank makes more sense, such as when building a blog and generating the primary heading from frontmatter metadata, in which case a value of 2 can be defined here or the rule can be turned off.

Examples

ok.md

In

# Mercury

Out

No messages.

ok-delay.md

In

Mercury.

# Venus

Out

No messages.

not-ok.md

In

## Mercury

Venus.

Out

1:1-1:11: Unexpected first heading rank `2`, expected rank `1`

ok.md

When configured with 2.

In

## Mercury

Venus.

Out

No messages.

ok-html.md

In

<div>Mercury.</div>

<h1>Venus</h1>

Out

No messages.

ok-mdx.mdx

In

👉 Note: this example uses MDX (remark-mdx).

<div>Mercury.</div>

<h1>Venus</h1>

Out

No messages.

not-ok-options.md

When configured with '🌍'.

Out

1:1: Unexpected value `🌍` for `options`, expected `1`, `2`, `3`, `4`, `5`, or `6`

Compatibility

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, remark-lint-first-heading-level@4, compatible with Node.js 16.

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