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
- 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@3'
In browsers with esm.sh:
<script type="module">
import remarkLintFirstHeadingLevel from 'https://esm.sh/remark-lint-first-heading-level@3?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 types Depth and 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).
Depth
Depth (TypeScript type).
Type
type Depth = 1 | 2 | 3 | 4 | 5 | 6
Options
Configuration (TypeScript type).
Type
type Options = Depth
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.
Examples
ok.md
In
# The default is to expect a level one heading
Out
No messages.
ok-html.md
In
<h1>An HTML heading is also seen by this rule.</h1>
Out
No messages.
ok-delayed.md
In
You can use markdown content before the heading.
<div>Or non-heading HTML</div>
<h1>So the first heading, be it HTML or markdown, is checked</h1>
Out
No messages.
not-ok.md
In
## Bravo
Paragraph.
Out
1:1-1:9: First heading level should be `1`
not-ok-html.md
In
<h2>Charlie</h2>
Paragraph.
Out
1:1-1:17: First heading level should be `1`
ok.md
When configured with 2.
In
## Delta
Paragraph.
Out
No messages.
ok-html.md
When configured with 2.
In
<h2>Echo</h2>
Paragraph.
Out
No messages.
not-ok.md
When configured with 2.
In
# Foxtrot
Paragraph.
Out
1:1-1:10: First heading level should be `2`
not-ok-html.md
When configured with 2.
In
<h1>Golf</h1>
Paragraph.
Out
1:1-1:14: First heading level should be `2`
ok.mdx
In
👉 Note: this example uses MDX (
remark-mdx).
In <b>MDX</b>, JSX is supported.
<h1>First heading</h1>
Out
No messages.
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@3, compatible with Node.js 12.
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.