remark-lint-file-extension

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[remark-lint][github-remark-lint] rule to warn for unexpected file extensions.

Contents

* What is this?
* When should I use this?
* Presets
* Install
* Use
* API
* [unified().use(remarkLintFileExtension[, options])](#unifieduseremarklintfileextension-options)
* Extensions
* Options
* Recommendation
* Examples
* Compatibility
* Contribute
* License

What is this?

This package checks the file extension.

When should I use this?

You can use this package to check that file extensions are consistent.

Presets

This plugin is included in the following presets:

| Preset | Options |
| - | - |
| remark-preset-lint-markdown-style-guide | 'md' |

Install

This package is [ESM only][github-gist-esm].
In Node.js (version 16+),
install with [npm][npm-install]:

``sh
npm install remark-lint-file-extension
`

In Deno with [esm.sh][esm-sh]:

`js
import remarkLintFileExtension from 'https://esm.sh/remark-lint-file-extension@3'
`

In browsers with [esm.sh][esm-sh]:

`html

`

Use

On the API:

`js
import remarkLint from 'remark-lint'
import remarkLintFileExtension from 'remark-lint-file-extension'
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(remarkLintFileExtension)
.use(remarkStringify)
.process(file)

console.error(reporter(file))
`

On the CLI:

`sh
remark --frail --use remark-lint --use remark-lint-file-extension .
`

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

`diff
…
"remarkConfig": {
"plugins": [
…
"remark-lint",
+ "remark-lint-file-extension",
…
]
}
…
`

API

This package exports no identifiers.
It exports the [TypeScript][typescript] types
[Extensions][api-extensions] and
[Options][api-options].
The default export is
[remarkLintFileExtension][api-remark-lint-file-extension].

$3

Warn for unexpected extensions.

###### Parameters

* options ([Extensions][api-extensions] or [Options][api-options],
optional)
— configuration

###### Returns

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

$3

File extension(s) (TypeScript type).

###### Type

`ts
type Extensions = Array | string
`

$3

Configuration (TypeScript type).

###### Fields

* allowExtensionless (boolean, default: true)
— allow no file extension such as AUTHORS or LICENSE
* extensions ([Extensions][api-extensions], default: ['mdx', 'md'])
— allowed file extension(s)

Recommendation

Use md as it’s the most common.
Also use md when your markdown contains common syntax extensions (such as
GFM, frontmatter, or math).
Do not use md for MDX: use mdx instead.

Examples

##### readme.md

###### Out

No messages.

##### readme.mdx

###### Out

No messages.

##### readme

###### Out

No messages.

##### readme

When configured with { allowExtensionless: false }.

###### Out

`text
1:1: Unexpected missing file extension, expected mdx or md
`

##### readme.mkd

###### Out

`text
1:1: Unexpected file extension mkd, expected mdx or md
`

##### readme.mkd

When configured with 'mkd'.

###### Out

No messages.

##### readme.css

When configured with [
'markdown', 'md',
'mdown', 'mdwn',
'mdx', 'mkd',
'mkdn', 'mkdown',
'ron'
].

###### Out

`text
1:1: Unexpected file extension css, expected markdown, md, mdown, …
`

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-file-extension@3,
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-extensions]: #extensions

[api-options]: #options

[api-remark-lint-file-extension]: #unifieduseremarklintfileextension-options

[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-file-extension.svg

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

[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-file-extension

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

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

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

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