# remark-lint-no-html
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[![Downloads][badge-downloads-image]][badge-downloads-url]
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[![Backers][badge-funding-backers-image]][badge-funding-url]
[![Chat][badge-chat-image]][badge-chat-url]
[`remark-lint`][github-remark-lint] rule to warn when HTML is used.
## Contents
* [What is this?](#what-is-this)
* [When should I use this?](#when-should-i-use-this)
* [Presets](#presets)
* [Install](#install)
* [Use](#use)
* [API](#api)
* [`unified().use(remarkLintNoHtml[, options])`](#unifieduseremarklintnohtml-options)
* [`Options`](#options)
* [Examples](#examples)
* [Compatibility](#compatibility)
* [Contribute](#contribute)
* [License](#license)
## What is this?
This package checks HTML.
## When should I use this?
You can use this package to check that no HTML is used.
## Presets
This plugin is not included in presets maintained here.
## Install
This package is [ESM only][github-gist-esm].
In Node.js (version 16+),
install with [npm][npm-install]:
```sh
npm install remark-lint-no-html
```
In Deno with [`esm.sh`][esm-sh]:
```js
import remarkLintNoHtml from 'https://esm.sh/remark-lint-no-html@4'
```
In browsers with [`esm.sh`][esm-sh]:
```html
```
## Use
On the API:
```js
import remarkLint from 'remark-lint'
import remarkLintNoHtml from 'remark-lint-no-html'
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(remarkLintNoHtml)
.use(remarkStringify)
.process(file)
console.error(reporter(file))
```
On the CLI:
```sh
remark --frail --use remark-lint --use remark-lint-no-html .
```
On the CLI in a config file (here a `package.json`):
```diff
…
"remarkConfig": {
"plugins": [
…
"remark-lint",
+ "remark-lint-no-html",
…
]
}
…
```
## API
This package exports no identifiers.
It exports the [TypeScript][typescript] type
[`Options`][api-options].
The default export is
[`remarkLintNoHtml`][api-remark-lint-no-html].
### `unified().use(remarkLintNoHtml[, options])`
Warn when HTML is used.
###### Parameters
* `options` ([`Options`][api-options], optional)
— configuration
###### Returns
Transform ([`Transformer` from `unified`][github-unified-transformer]).
### `Options`
Configuration (TypeScript type).
###### Fields
* `allowComments` (`boolean`, default: `true`)
— allow comments or not
## Examples
##### `ok.md`
###### In
```markdown
# Mercury
```
###### Out
No messages.
##### `not-ok.md`
###### In
```markdown
Mercury
```
###### Out
```text
1:1-1:17: Unexpected HTML, use markdown instead
```
##### `not-ok.md`
When configured with `{ allowComments: false }`.
###### In
```markdown
```
###### Out
```text
1:1-1:15: Unexpected HTML, use markdown instead
```
## 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-no-html@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-options]: #options
[api-remark-lint-no-html]: #unifieduseremarklintnohtml-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-no-html.svg
[badge-downloads-url]: https://www.npmjs.com/package/remark-lint-no-html
[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-no-html
[badge-size-url]: https://bundlejs.com/?q=remark-lint-no-html
[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