remark-lint-fenced-code-flag

remark-lint-fenced-code-flag

remark-lint rule to check that language flags of fenced code are used.

Contents

• What is this?
• When should I use this?
• Presets
• Install
• Use
• API
  • unified().use(remarkLintFencedCodeFlag[, config])
• Recommendation
• Examples
• Compatibility
• Contribute
• License

What is this?

This package is a unified (remark) plugin, specifically a remark-lint rule. Lint rules check markdown code style.

When should I use this?

You can use this package to check that language flags of fenced code are used and consistent.

Presets

This rule is included in the following presets:

Preset	Setting
remark-preset-lint-markdown-style-guide	{ allowEmpty: false }

Install

This package is ESM only. In Node.js (version 12.20+, 14.14+, or 16.0+), install with npm:

npm install remark-lint-fenced-code-flag

In Deno with esm.sh:

import remarkLintFencedCodeFlag from 'https://esm.sh/remark-lint-fenced-code-flag@3'

In browsers with esm.sh:

<script type="module">
  import remarkLintFencedCodeFlag from 'https://esm.sh/remark-lint-fenced-code-flag@3?bundle'
</script>

Use

On the API:

import {read} from 'to-vfile'
import {reporter} from 'vfile-reporter'
import {remark} from 'remark'
import remarkLint from 'remark-lint'
import remarkLintFencedCodeFlag from 'remark-lint-fenced-code-flag'

main()

async function main() {
  const file = await remark()
    .use(remarkLint)
    .use(remarkLintFencedCodeFlag)
    .process(await read('example.md'))

  console.error(reporter(file))
}

On the CLI:

remark --use remark-lint --use remark-lint-fenced-code-flag example.md

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

 …
 "remarkConfig": {
   "plugins": [
     …
     "remark-lint",
+    "remark-lint-fenced-code-flag",
     …
   ]
 }
 …

API

This package exports no identifiers. The default export is remarkLintFencedCodeFlag.

unified().use(remarkLintFencedCodeFlag[, config])

This rule supports standard configuration that all remark lint rules accept (such as false to turn it off or [1, options] to configure it).

The following options (default: undefined) are accepted:

• Array<string> — as if passing {flags: options}
• Object with the following fields:
  • allowEmpty (boolean, default: false) — allow language flags to be omitted
  • flags (Array<string> default: []) — specific flags to allow (other flags will result in a warning)

Recommendation

While omitting the language flag is perfectly fine to signal that the code is plain text, it could point to a mistake. It’s recommended to instead use a certain flag for plain text (such as txt) and to turn this rule on.

Examples

ok.md

In

```alpha
bravo()
```

Out

No messages.

not-ok.md

In

```
alpha()
```

Out

1:1-3:4: Missing code language flag

ok.md

When configured with { allowEmpty: true }.

In

```
alpha()
```

Out

No messages.

not-ok.md

When configured with { allowEmpty: false }.

In

```
alpha()
```

Out

1:1-3:4: Missing code language flag

ok.md

When configured with [ 'alpha' ].

In

```alpha
bravo()
```

Out

No messages.

ok.md

When configured with { flags: [ 'alpha' ] }.

In

```alpha
bravo()
```

Out

No messages.

not-ok.md

When configured with [ 'charlie' ].

In

```alpha
bravo()
```

Out

1:1-3:4: Incorrect code language flag

Compatibility

Projects maintained by the unified collective are compatible with all maintained versions of Node.js. As of now, that is Node.js 12.20+, 14.14+, and 16.0+. Our projects sometimes work with older versions, but this is not guaranteed.

Contribute

See contributing.md in remarkjs/.github for ways to get started. See support.md for ways to get help.

This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.

License

MIT © Titus Wormer