remark-lint-no-duplicate-definitions

remark-lint rule to warn when identifiers are defined multiple times.

Contents

• What is this?
• When should I use this?
• Presets
• Install
• Use
• API
  • unified().use(remarkLintNoDuplicateDefinitions)
• Recommendation
• Examples
• Compatibility
• Contribute
• License

What is this?

This package checks that defined identifiers are unique.

When should I use this?

You can use this package to check that definitions are useful.

Presets

This plugin is included in the following presets:

Preset	Options
remark-preset-lint-recommended

Install

This package is ESM only. In Node.js (version 16+), install with npm:

npm install remark-lint-no-duplicate-definitions

In Deno with esm.sh:

import remarkLintNoDuplicateDefinitions from 'https://esm.sh/remark-lint-no-duplicate-definitions@4'

In browsers with esm.sh:

<script type="module">
  import remarkLintNoDuplicateDefinitions from 'https://esm.sh/remark-lint-no-duplicate-definitions@4?bundle'
</script>

Use

On the API:

import remarkLint from 'remark-lint'
import remarkLintNoDuplicateDefinitions from 'remark-lint-no-duplicate-definitions'
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(remarkLintNoDuplicateDefinitions)
  .use(remarkStringify)
  .process(file)

console.error(reporter(file))

On the CLI:

remark --frail --use remark-lint --use remark-lint-no-duplicate-definitions .

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

 …
 "remarkConfig": {
   "plugins": [
     …
     "remark-lint",
+    "remark-lint-no-duplicate-definitions",
     …
   ]
 }
 …

API

This package exports no identifiers. It exports no additional TypeScript types. The default export is remarkLintNoDuplicateDefinitions.

unified().use(remarkLintNoDuplicateDefinitions)

Warn when identifiers are defined multiple times.

Parameters

There are no options.

Returns

Transform (Transformer from unified).

Recommendation

It’s a mistake when the same identifier is defined multiple times.

Examples

ok.md

In

[mercury]: https://example.com/mercury/
[venus]: https://example.com/venus/

Out

No messages.

not-ok.md

In

[mercury]: https://example.com/mercury/
[mercury]: https://example.com/venus/

Out

2:1-2:38: Unexpected definition with an already defined identifier (`mercury`), expected unique identifiers

gfm.md

In

👉 Note: this example uses GFM (remark-gfm).

Mercury[^mercury].

[^mercury]:
  Mercury is the first planet from the Sun and the smallest in the Solar
  System.

[^mercury]:
  Venus is the second planet from the Sun.

Out

7:1-7:12: Unexpected footnote definition with an already defined identifier (`mercury`), expected unique identifiers

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-duplicate-definitions@4, compatible with Node.js 16.

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