remark-lint-heading-increment
Version:
remark-lint rule to warn when headings increment with more than 1 level at a time
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Markdown
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[`remark-lint`][github-remark-lint] rule to warn when heading ranks increment with more than
1 at a time.
* [What is this?](
* [When should I use this?](
* [Presets](
* [Install](
* [Use](
* [API](
* [`unified().use(remarkLintHeadingIncrement)`](
* [Recommendation](
* [Examples](
* [Compatibility](
* [Contribute](
* [License](
This package checks the increase of headings.
You can use this package to check the increase of headings.
This plugin is included in the following presets:
| Preset | Options |
| - | - |
| [`remark-preset-lint-markdown-style-guide`](https://github.com/remarkjs/remark-lint/tree/main/packages/remark-preset-lint-markdown-style-guide) | |
This package is [ESM only][github-gist-esm].
In Node.js (version 16+),
install with [npm][npm-install]:
```sh
npm install remark-lint-heading-increment
```
In Deno with [`esm.sh`][esm-sh]:
```js
import remarkLintHeadingIncrement from 'https://esm.sh/remark-lint-heading-increment@4'
```
In browsers with [`esm.sh`][esm-sh]:
```html
<script type="module">
import remarkLintHeadingIncrement from 'https://esm.sh/remark-lint-heading-increment@4?bundle'
</script>
```
On the API:
```js
import remarkLint from 'remark-lint'
import remarkLintHeadingIncrement from 'remark-lint-heading-increment'
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(remarkLintHeadingIncrement)
.use(remarkStringify)
.process(file)
console.error(reporter(file))
```
On the CLI:
```sh
remark --frail --use remark-lint --use remark-lint-heading-increment .
```
On the CLI in a config file (here a `package.json`):
```diff
…
"remarkConfig": {
"plugins": [
…
"remark-lint",
+ "remark-lint-heading-increment",
…
]
}
…
```
This package exports no identifiers.
It exports no additional [TypeScript][typescript] types.
The default export is
[`remarkLintHeadingIncrement`][api-remark-lint-heading-increment].
Warn when heading ranks increment with more than 1 at a time.
There are no options.
Transform ([`Transformer` from `unified`][github-unified-transformer]).
While markdown is not only used for HTML,
HTML accessibility guidelines state that headings should increment by one at
a time.
As in,
say the previous heading had a rank of 2 (so `<h2>`),
then the following heading that is to be considered “inside” it should have
a rank of 3 (`<h3>`).
Due to this,
when HTML output is a goal of the document,
it’s recommended that this rule is turned on.
```markdown
```
No messages.
```markdown
```
No messages.
```markdown
```
```text
3:1-3:23: Unexpected heading rank `3`, exected rank `2`
5:1-5:20: Unexpected heading rank `3`, exected rank `2`
9:1-9:16: Unexpected heading rank `4`, exected rank `3`
```
```markdown
<b>Mercury</b> is the first planet from the Sun and the smallest
in the Solar System.
<h3>Internal structure</h3>
<h2>Orbit, rotation, and longitude</h2>
```
```text
6:1-6:28: Unexpected heading rank `3`, exected rank `2`
```
> 👉 **Note**: this example uses
> MDX ([`remark-mdx`][github-remark-mdx]).
```mdx
<b>Mercury</b> is the first planet from the Sun and the smallest
in the Solar System.
<h3>Internal structure</h3>
<h2>Orbit, rotation, and longitude</h2>
```
```text
6:1-6:28: Unexpected heading rank `3`, exected rank `2`
```
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-increment@4`,
compatible with Node.js 16.
See [`contributing.md`][github-dotfiles-contributing] in [`remarkjs/.github`][github-dotfiles-health] for ways
to get started.
See [`support.md`][github-dotfiles-support] for ways to get help.
This project has a [code of conduct][github-dotfiles-coc].
By interacting with this repository, organization, or community you agree to
abide by its terms.
[][file-license] © [Titus Wormer][author]
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