remark-lint-heading-increment

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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

What is this?

This package checks the increase of headings.

When should I use this?

You can use this package to check the increase of headings.

Presets

This plugin is included in the following presets:

Install

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`

`Use`

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", … ] } …`

`API`

This package exports no identifiers. It exports no additional [TypeScript][typescript] types. The default export is [remarkLintHeadingIncrement][api-remark-lint-heading-increment].

`$3`

Warn when heading ranks increment with more than 1 at a time.

###### Parameters

There are no options.

###### Returns

Transform ([Transformer from unified][github-unified-transformer]).

`Recommendation`

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

`), then the following heading that is to be considered “inside” it should have a rank of 3 (`

`). Due to this, when HTML output is a goal of the document, it’s recommended that this rule is turned on. Examples`
`#####` ok.md
`###### In`
``markdown`

`Mercury`

`Nomenclature`


###### Out
No messages.

##### also-ok.md

###### In

`markdown #### Impact basins and craters

#### Plains

#### Compressional features`

###### Out

No messages.

##### not-ok.md

###### In

`markdown

`Mercury`

`$3`

`Observation history`

#### Mariner 10`

###### Out

`text 3:1-3:23: Unexpected heading rank3, exected rank 25:1-5:20: Unexpected heading rank3, exected rank 29:1-9:16: Unexpected heading rank4, exected rank 3`

##### html.md

###### In

`markdown

`Mercury`

Mercury is the first planet from the Sun and the smallest in the Solar System.

`Internal structure`

`Orbit, rotation, and longitude`


###### Out

`text 6:1-6:28: Unexpected heading rank3, exected rank 2`

##### mdx.mdx

###### In

> 👉 Note: this example uses > MDX ([remark-mdx][github-remark-mdx]).

`mdx

`Mercury`

Mercury is the first planet from the Sun and the smallest in the Solar System.

`Internal structure`

`Orbit, rotation, and longitude`


###### Out

`text 6:1-6:28: Unexpected heading rank3, exected rank 2`

`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-increment@4, compatible with Node.js 16.

`Contribute`

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.

License

[MIT][file-license] © [Titus Wormer][author]

[api-remark-lint-heading-increment]: #unifieduseremarklintheadingincrement

[author]: https://wooorm.com

[badge-build-image]: https://github.com/remarkjs/remark-lint/workflows/main/badge.svg

[badge-build-url]: https://github.com/remarkjs/remark-lint/actions

[badge-chat-image]: https://img.shields.io/badge/chat-discussions-success.svg

[badge-chat-url]: https://github.com/remarkjs/remark/discussions

[badge-coverage-image]: https://img.shields.io/codecov/c/github/remarkjs/remark-lint.svg

[badge-coverage-url]: https://codecov.io/github/remarkjs/remark-lint

[badge-downloads-image]: https://img.shields.io/npm/dm/remark-lint-heading-increment.svg

[badge-downloads-url]: https://www.npmjs.com/package/remark-lint-heading-increment

[badge-funding-backers-image]: https://opencollective.com/unified/backers/badge.svg

[badge-funding-sponsors-image]: https://opencollective.com/unified/sponsors/badge.svg

[badge-funding-url]: https://opencollective.com/unified

[badge-size-image]: https://img.shields.io/bundlejs/size/remark-lint-heading-increment

[badge-size-url]: https://bundlejs.com/?q=remark-lint-heading-increment

[esm-sh]: https://esm.sh

[file-license]: https://github.com/remarkjs/remark-lint/blob/main/license

[github-dotfiles-coc]: https://github.com/remarkjs/.github/blob/main/code-of-conduct.md

[github-dotfiles-contributing]: https://github.com/remarkjs/.github/blob/main/contributing.md

[github-dotfiles-health]: https://github.com/remarkjs/.github

[github-dotfiles-support]: https://github.com/remarkjs/.github/blob/main/support.md

[github-gist-esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c

[github-remark-lint]: https://github.com/remarkjs/remark-lint

[github-remark-mdx]: https://mdxjs.com/packages/remark-mdx/

[github-unified-transformer]: https://github.com/unifiedjs/unified#transformer

[npm-install]: https://docs.npmjs.com/cli/install

[typescript]: https://www.typescriptlang.org

remark-lint-heading-increment

[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

What is this?

This package checks the increase of headings.

When should I use this?

You can use this package to check the increase of headings.

Presets

This plugin is included in the following presets:

Install

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`

`Use`

On the API:

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", … ] } …`

`API`

This package exports no identifiers. It exports no additional [TypeScript][typescript] types. The default export is [remarkLintHeadingIncrement][api-remark-lint-heading-increment].

`$3`

Warn when heading ranks increment with more than 1 at a time.

###### Parameters

There are no options.

###### Returns

Transform ([Transformer from unified][github-unified-transformer]).

`Recommendation`

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

`), then the following heading that is to be considered “inside” it should have a rank of 3 (`

`). Due to this, when HTML output is a goal of the document, it’s recommended that this rule is turned on. Examples`
`#####` ok.md
`###### In`
``markdown`

`Mercury`

`Nomenclature`


###### Out
No messages.

##### also-ok.md

###### In

`markdown #### Impact basins and craters

#### Plains

#### Compressional features`

###### Out

No messages.

##### not-ok.md

###### In

`markdown

`Mercury`

`$3`

`Observation history`

#### Mariner 10`

###### Out

`text 3:1-3:23: Unexpected heading rank3, exected rank 25:1-5:20: Unexpected heading rank3, exected rank 29:1-9:16: Unexpected heading rank4, exected rank 3`

##### html.md

###### In

`markdown

`Mercury`

Mercury is the first planet from the Sun and the smallest in the Solar System.

`Internal structure`

`Orbit, rotation, and longitude`


###### Out

`text 6:1-6:28: Unexpected heading rank3, exected rank 2`

##### mdx.mdx

###### In

> 👉 Note: this example uses > MDX ([remark-mdx][github-remark-mdx]).

`mdx

`Mercury`

Mercury is the first planet from the Sun and the smallest in the Solar System.

`Internal structure`

`Orbit, rotation, and longitude`


###### Out