remark-lint rule to warn when headings violate a given style.
Contents
What is this?
This package checks the style of headings.
When should I use this?
You can use this package to check that the style of headings is consistent.
Presets
This plugin is included in the following presets:
Install
This package is ESM only. In Node.js (version 16+), install with npm:
npm install remark-lint-heading-style
In Deno with esm.sh:
import remarkLintHeadingStyle from 'https://esm.sh/remark-lint-heading-style@4'
In browsers with esm.sh:
<script type="module">
import remarkLintHeadingStyle from 'https://esm.sh/remark-lint-heading-style@4?bundle'
</script>
Use
On the API:
import remarkLint from 'remark-lint'
import remarkLintHeadingStyle from 'remark-lint-heading-style'
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(remarkLintHeadingStyle)
.use(remarkStringify)
.process(file)
console.error(reporter(file))
On the CLI:
remark --frail --use remark-lint --use remark-lint-heading-style .
On the CLI in a config file (here a package.json):
…
"remarkConfig": {
"plugins": [
…
"remark-lint",
+ "remark-lint-heading-style",
…
]
}
…
API
This package exports no identifiers. It exports the TypeScript types Options and Style. The default export is remarkLintHeadingStyle.
Warn when headings violate a given style.
Parameters
options (Options, default: 'consistent') — preferred style or whether to detect the first style and warn for further differences
Returns
Transform (Transformer from unified).
Options
Configuration (TypeScript type).
Type
type Options = Style | 'consistent'
Style
Style (TypeScript type).
Type
type Style = 'atx' | 'atx-closed' | 'setext'
Recommendation
Setext headings are limited in that they can only construct headings with a rank of one and two. They do allow multiple lines of content where ATX only allows one line. The number of used markers in their underline does not matter, leading to either:
- 1 marker (
Hello\n-), which is the bare minimum, and for rank 2 headings looks suspiciously like an empty list item - using as many markers as the content (
Hello\n-----), which is hard to maintain and diff - an arbitrary number (
Hello\n---), which for rank 2 headings looks suspiciously like a thematic break
Setext headings are also uncommon. Using a sequence of hashes at the end of ATX headings is even more uncommon. Due to this, it’s recommended to use ATX headings, without closing hashes.
Fix
remark-stringify formats headings as ATX by default. The other styles can be configured with setext: true or closeAtx: true.
Examples
ok.md
When configured with 'atx'.
In
# Mercury
## Venus
### Earth
Out
No messages.
ok.md
When configured with 'atx-closed'.
In
# Mercury ##
## Venus ##
### Earth ###
Out
No messages.
ok.md
When configured with 'setext'.
In
Mercury
=======
Venus
-----
### Earth
Out
No messages.
not-ok.md
In
Mercury
=======
## Venus
### Earth ###
Out
4:1-4:9: Unexpected ATX heading, expected setext
6:1-6:14: Unexpected ATX (closed) heading, expected setext
not-ok.md
When configured with '🌍'.
Out
1:1: Unexpected value `🌍` for `options`, expected `'atx'`, `'atx-closed'`, `'setext'`, or `'consistent'`
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-heading-style@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