unified-lint-rule

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[unified][github-unified] helper to help make lint rules.

Contents

* What is this?
* When should I use this?
* Install
* Use
* API
* lintRule(meta, rule)
* Label
* Meta
* Next
* Rule
* Severity
* Compatibility
* Contribute
* License

What is this?

This package is a helper that makes it a bit easier to create linting rules.

When should I use this?

You can use this package when you want to make custom lint rules.

Install

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

``sh
npm install unified-lint-rule
`

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

`js
import {lintRule} from 'https://esm.sh/unified-lint-rule@3'
`

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

`html

`

Use

`js
import {lintRule} from 'unified-lint-rule'

const remarkLintFileExtension = lintRule(
'remark-lint:file-extension',
function (tree, file, options) {
const ext = file.extname
const option = options || 'md'

if (ext && ext.slice(1) !== option) {
file.message('Incorrect extension: use ' + option + '')
}
}
)

export default remarkLintFileExtension
`

API

This package exports the identifier
[lintRule][api-lint-rule].
It exports the [TypeScript][typescript] types
[Label][api-label],
[Meta][api-meta],
[Next][api-next], and
[Severity][api-severity].
There is no default export.

$3

Create a plugin.

###### Parameters

* meta ([Meta][api-meta] or string)
— info or origin
* rule ([Rule][api-rule])
— rule

###### Returns

Plugin ([Plugin from unified][github-unified-plugin]).

$3

Severity label (TypeScript type);
'off': 0, 'on' and warn: 1, 'error': 2.

###### Type

`ts
type Label = 'error' | 'on' | 'off' | 'warn'
`

$3

Rule metadata (TypeScript type).

###### Fields

* origin (string)
— name of the lint rule
* url (string, optional)
— link to documentation

$3

Callback passed to rules (TypeScript type).

If the signature of a rule accepts a fourth argument,
the rule may perform asynchronous operations,
and must call it.

###### Parameters

* error (Error, optional)
— fatal error to stop linting

###### Returns

Nothing (undefined).

$3

Rule (TypeScript type).

###### Parameters

* tree ([Node from unist][github-unist-node])
— tree
* file ([VFile][github-vfile])
— file
* options (unknown, optional)
— parameter

###### Returns

Nothing (Promise or undefined).

$3

Severity number (TypeScript type);
0: 'off', 1: 'on' and warn, 2: 'error'.

###### Type

`ts
type Severity = 0 | 1 | 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,
unified-lint-rule@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-label]: #label

[api-lint-rule]: #lintrulemeta-rule

[api-meta]: #meta

[api-next]: #next

[api-rule]: #rule

[api-severity]: #severity

[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/unified-lint-rule.svg

[badge-downloads-url]: https://www.npmjs.com/package/unified-lint-rule

[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/unified-lint-rule

[badge-size-url]: https://bundlejs.com/?q=unified-lint-rule

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

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

[github-unist-node]: https://github.com/syntax-tree/unist#node

[github-vfile]: https://github.com/vfile/vfile

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

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