remark-lint-no-undefined-references

What is remark-lint-no-undefined-references?

The `remark-lint-no-undefined-references` package is a plugin for `remark-lint` that checks for undefined references in Markdown files. It helps ensure that all reference links in your Markdown documents are defined, preventing broken links and improving document integrity.

What are remark-lint-no-undefined-references's main functionalities?

Check for undefined references

This feature checks for any undefined references in a Markdown file. The code sample demonstrates how to use `remark-lint-no-undefined-references` with `remark` to process a Markdown string and report any undefined references.

const remark = require('remark');
const lint = require('remark-lint');
const noUndefinedReferences = require('remark-lint-no-undefined-references');

remark()
  .use(lint)
  .use(noUndefinedReferences)
  .process('[undefined]: https://example.com', function (err, file) {
    console.error(report(err || file));
  });

Other packages similar to remark-lint-no-undefined-references

remark-lint-no-unused-definitions

The `remark-lint-no-unused-definitions` package checks for unused definitions in Markdown files. While `remark-lint-no-undefined-references` ensures that all references are defined, `remark-lint-no-unused-definitions` ensures that all definitions are used. Both packages help maintain the integrity of Markdown documents by addressing different aspects of link and reference management.

remark-lint-no-dead-urls

The `remark-lint-no-dead-urls` package checks for dead URLs in Markdown files. It ensures that all URLs in the document are reachable, which complements `remark-lint-no-undefined-references` by ensuring that not only are references defined, but the URLs they point to are valid and accessible.

README

remark-lint-no-undefined-references

remark-lint rule to warn when undefined definitions are referenced.

Contents

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

What is this?

This package checks that referenced definitions are defined.

When should I use this?

You can use this package to check for broken references.

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-undefined-references

In Deno with esm.sh:

import remarkLintNoUndefinedReferences from 'https://esm.sh/remark-lint-no-undefined-references@5'

In browsers with esm.sh:

<script type="module">
  import remarkLintNoUndefinedReferences from 'https://esm.sh/remark-lint-no-undefined-references@5?bundle'
</script>

Use

On the API:

import remarkLint from 'remark-lint'
import remarkLintNoUndefinedReferences from 'remark-lint-no-undefined-references'
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(remarkLintNoUndefinedReferences)
  .use(remarkStringify)
  .process(file)

console.error(reporter(file))

On the CLI:

remark --frail --use remark-lint --use remark-lint-no-undefined-references .

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

 …
 "remarkConfig": {
   "plugins": [
     …
     "remark-lint",
+    "remark-lint-no-undefined-references",
     …
   ]
 }
 …

API

This package exports no identifiers. It exports the TypeScript type Options. The default export is remarkLintNoUndefinedReferences.

unified().use(remarkLintNoUndefinedReferences[, options])

Warn when undefined definitions are referenced.

Parameters

• options (Options, optional) — configuration

Returns

Transform (Transformer from unified).

Options

Configuration (TypeScript type).

Fields

• allow (Array<RegExp | string>, optional) — list of values to allow between [ and ]
• allowShortcutLink (boolean, default: false) — allow shortcut references, which are just brackets such as [text]

Recommendation

Shortcut references use an implicit syntax that could also occur as plain text. To illustrate, it is reasonable to expect an author adding […] to abbreviate some text somewhere in a document:

> Some […] quote.

This isn’t a problem, but it might become one when an author later adds a definition:

Some new text […][].

[…]: #read-more

The second author might expect only their newly added text to form a link, but their changes also result in a link for the text by the first author.

Examples

ok.md

In

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

Venus is the second planet from the [Sun.

Earth is the third planet from the \[Sun] and the only astronomical object
known to harbor life\.

Mars is the fourth planet from the Sun: [].

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

Out

No messages.

not-ok.md

In

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

[Venus][] is the second planet from the Sun.

[Earth][earth] is the third planet from the Sun and the only astronomical
object known to harbor life.

![Mars] is the fourth planet from the Sun in the [Solar
System].

> Jupiter is the fifth planet from the Sun and the largest in the [Solar
> System][].

[Saturn][ is the sixth planet from the Sun and the second-largest
in the Solar System, after Jupiter.

[*Uranus*][] is the seventh planet from the Sun.

[Neptune][neptune][more] is the eighth and farthest planet from the Sun.

Out

1:1-1:10: Unexpected reference to undefined definition, expected corresponding definition (`mercury`) for a link or escaped opening bracket (`\[`) for regular text
4:1-4:10: Unexpected reference to undefined definition, expected corresponding definition (`venus`) for a link or escaped opening bracket (`\[`) for regular text
6:1-6:15: Unexpected reference to undefined definition, expected corresponding definition (`earth`) for a link or escaped opening bracket (`\[`) for regular text
9:2-9:8: Unexpected reference to undefined definition, expected corresponding definition (`mars`) for an image or escaped opening bracket (`\[`) for regular text
9:50-10:8: Unexpected reference to undefined definition, expected corresponding definition (`solar system`) for a link or escaped opening bracket (`\[`) for regular text
12:67-13:12: Unexpected reference to undefined definition, expected corresponding definition (`solar > system`) for a link or escaped opening bracket (`\[`) for regular text
15:1-15:9: Unexpected reference to undefined definition, expected corresponding definition (`saturn`) for a link or escaped opening bracket (`\[`) for regular text
18:1-18:13: Unexpected reference to undefined definition, expected corresponding definition (`*uranus*`) for a link or escaped opening bracket (`\[`) for regular text
20:1-20:19: Unexpected reference to undefined definition, expected corresponding definition (`neptune`) for a link or escaped opening bracket (`\[`) for regular text
20:19-20:25: Unexpected reference to undefined definition, expected corresponding definition (`more`) for a link or escaped opening bracket (`\[`) for regular text

ok-allow.md

When configured with { allow: [ '…' ] }.

In

Mercury is the first planet from the Sun and the smallest in the Solar
System. […]

Out

No messages.

source.md

When configured with { allow: [ { source: '^mer' }, 'venus' ] }.

In

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

[Venus][] is the second planet from the Sun.

Out

No messages.

gfm.md

In

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

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

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

Out

1:8-1:18: Unexpected reference to undefined definition, expected corresponding definition (`mercury`) for a footnote or escaped opening bracket (`\[`) for regular text

gfm-table.md

In

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

| [Planet]          | [Radius]  |
| ----------------- | --------- |
| [Mercury]         | 2439.7 km |

[planet]: https://example.com/planet/

Out

1:23-1:31: Unexpected reference to undefined definition, expected corresponding definition (`radius`) for a link or escaped opening bracket (`\[`) for regular text
3:3-3:12: Unexpected reference to undefined definition, expected corresponding definition (`mercury`) for a link or escaped opening bracket (`\[`) for regular text

allow-shortcut-link.md

When configured with { allowShortcutLink: true }.

In

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

[Venus][] is the second planet from the Sun.

[Earth][earth] is the third planet from the Sun and the only astronomical object
known to harbor life.

Out

4:1-4:10: Unexpected reference to undefined definition, expected corresponding definition (`venus`) for a link or escaped opening bracket (`\[`) for regular text
6:1-6:15: Unexpected reference to undefined definition, expected corresponding definition (`earth`) for a link or escaped opening bracket (`\[`) for regular text

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-undefined-references@5, 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