remark-validate-links

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remark plugin to check that markdown links and images point to existing local files and headings in a Git repo.
For example, this document does not have a heading named Hello. So if we’d link to it ([welcome](#hello)), we’d get a warning. Links to headings in other markdown documents (examples/foo.md#hello) and links to files (license or index.js) are also checked.
This is specifically for Git repos. Like this one. Not for say a website.
Contents
What is this?
When should I use this?
Install
Use
API
* [`unified().use(remarkValidateLinks[, options])`](#unifieduseremarkvalidatelinks-options) * [`Options`](#options) * [`UrlConfig`](#urlconfig)
Examples
* [Example: CLI](#example-cli) * [Example: CLI in npm scripts](#example-cli-in-npm-scripts)
Integration
Types
Compatibility
Security
Related
Contribute
License
What is this?
This package is a unified (remark ) plugin to check local links in a Git repo.

When should I use this?

This project is useful if you have a Git repo, such as this one, with docs in markdown and links to headings and other files, and want to check whether they’re correct. Compared to other links checkers, this project can work offline (making it fast en prone to fewer false positives), and is specifically made for local links in Git repos. This plugin does not check external URLs (see remark-lint-no-dead-urlsremark-lint-no-dead-urls) or undefined references (see remark-lint-no-undefined-referencesremark-lint-no-undefined-references).

Install

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

npm install remark-validate-links

In Deno with esm.shesmsh:

import remarkValidateLinks from 'https://esm.sh/remark-validate-links@13'

In browsers with esm.shesmsh:

<script type="module">
  import remarkValidateLinks from 'https://esm.sh/remark-validate-links@13?bundle'
</script>

Use

Say we have the following file example.md in this project:

# Alpha

Links are checked:

This [exists](#alpha).
This [one does not](#apha).

# Bravo

Headings in `readme.md` are [checked](readme.md#no-such-heading).
And [missing files are reported](missing-example.js).

Definitions are also checked:




References w/o definitions are not checked: [delta]

…and a module example.js:

import {remark} from 'remark'
import remarkValidateLinks from 'remark-validate-links'
import {read} from 'to-vfile'
import {reporter} from 'vfile-reporter'

const file = await remark()
  .use(remarkValidateLinks)
  .process(await read('example.md'))

console.log(reporter(file))

…then running node example.js yields:

example.md
6:6-6:27   warning Cannot find heading for `#apha`; did you mean `alpha` missing-heading remark-validate-links:missing-heading
11:5-11:53 warning Cannot find file `missing-example.js`                 missing-file    remark-validate-links:missing-file
16:1-16:20 warning Cannot find heading for `#charlie`                    missing-heading remark-validate-links:missing-heading

⚠ 3 warnings

👉 Note: readme.md#no-such-heading is not warned about on the API, as it does not check headings in other markdown files. The remark CLI is able to do that.

API

This package exports no identifiers. The default export is remarkValidateLinksapi-remark-validate-links.

`unified().use(remarkValidateLinks[, options])`

Check that markdown links and images point to existing local files and headings in a Git repo.

⚠️ Important: The API in Node.js checks links to headings and files but does not check whether headings in other files exist. The API in browsers only checks links to headings in the same file. The CLI can check everything.

Parameters

options (Optionsapi-options, optional)

— configuration

Returns

Transform (Transformerunified-transformer).

`Options`

Configuration (TypeScript type).

Fields

repository (string or false, default: detected from Git remote)

— URL to hosted Git;
if you’re not in a Git repository, you must pass `false`;
if the repository resolves to something npm understands as a Git host such
as GitHub, GitLab, or Bitbucket, full URLs to that host (say,
`https://github.com/remarkjs/remark-validate-links/readme.md#install`) are
checked

root (string, default: local Git folder)

— path to Git root folder;
if both `root` and `repository` are nullish, the Git root is detected;
if `root` is not given but `repository` is, `file.cwd` is used

urlConfig (UrlConfigapi-url-config, default: detected from repo)

— config on how hosted Git works;
`github.com`, `gitlab.com`, or `bitbucket.org` work automatically;
otherwise, pass `urlConfig` manually

`UrlConfig`

Hosted Git info (TypeScript type).

Fields

headingPrefix (string, optional, example: '#', '#markdown-header-')

— prefix of headings

hostname (string, optional, example: 'github.com',

`'bitbucket.org'`)
— domain of URLs

lines (boolean, default: false)

— whether lines in files can be linked

path (string, optional, example:

`'/remarkjs/remark-validate-links/blob/'`,
`'/remarkjs/remark-validate-links/src/'`)
— path prefix before files

topAnchor (string, optional, example: #readme)

— hash to top of readme

Notes

For this repository (remarkjs/remark-validate-links on GitHub) urlConfig looks as follows:

{
  // Domain of URLs:
  hostname: 'github.com',
  // Path prefix before files:
  prefix: '/remarkjs/remark-validate-links/blob/',
  // Prefix of headings:
  headingPrefix: '#',
  // Hash to top of markdown documents:
  topAnchor: '#readme',
  // Whether lines in files can be linked:
  lines: true
}

If this project were hosted on Bitbucket, it would be:

{
  hostname: 'bitbucket.org',
  prefix: '/remarkjs/remark-validate-links/src/',
  headingPrefix: '#markdown-header-',
  lines: false
}

Examples

Example: CLI

It’s recommended to use remark-validate-links on the CLI with remark-cliremark-cli. Install both with npm :

npm install remark-cli remark-validate-links --save-dev

Let’s say we have a readme.md (this current document) and an example.md with the following text:

# Hello

Read more [whoops, this does not exist](#world).

This doesn’t exist either [whoops!](readme.md#foo).

But this does exist: [license](license).

So does this: [readme](readme.md#install).

Now, running ./node_modules/.bin/remark --use remark-validate-links . yields:

example.md
  3:11-3:48  warning  Link to unknown heading: `world`               missing-heading          remark-validate-links
  5:27-5:51  warning  Link to unknown heading in `readme.md`: `foo`  missing-heading-in-file  remark-validate-links

readme.md: no issues found

⚠ 2 warnings

Example: CLI in npm scripts

You can use remark-validate-links and remark-cliremark-cli in an npm script to check and format markdown in your project. Install both with npm :

npm install remark-cli remark-validate-links --save-dev

Then, add a format script and configuration to package.json:

{
  // …
  "scripts": {
    // …
    "format": "remark . --quiet --frail --output",
    // …
  },
  "remarkConfig": {
    "plugins": [
      "remark-validate-links"
    ]
  },
  // …
}

💡 Tip: Add other tools such as prettier or ESLint to check and format other files.
💡 Tip: Run ./node_modules/.bin/remark --help for help with remark-cli.

Now you check and format markdown in your project with:

npm run format

Integration

remark-validate-links can detect anchors on nodes through several properties on nodes:

node.data.hProperties.name — Used by

[`mdast-util-to-hast`][mdast-util-to-hast]
to create a `name` attribute, which anchors can link to

node.data.hProperties.id — Used by

[`mdast-util-to-hast`][mdast-util-to-hast]
to create an `id` attribute, which anchors can link to

node.data.id — Used potentially in the future by other tools to signal

unique identifiers on nodes

Types

This package is fully typed with TypeScript . It exports the additional types Optionsapi-options and UrlConfigapi-url-config.

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-validate-links@^13, compatible with Node.js 16.
This plugin works with unified version 6+, remark version 7+, and remark-cli version 8+.

Security

remark-validate-links, in Node, accesses the file system based on user content, and this may be dangerous. In Node git remote and git rev-parse also runs for processed files.
The tree is not modified, so there are no openings for cross-site scripting (XSS)wiki-xss attacks.

remark-lintremark-lint

— markdown code style linter

remark-lint-no-dead-urlsremark-lint-no-dead-urls

— check that external links are alive

Contribute

See contributing.mdcontributing in remarkjs/.githubhealth for ways to get started. See support.mdsupport for ways to get help.
This project has a code of conduct coc. By interacting with this repository, organization, or community you agree to abide by its terms.

remark-validate-links

Downloads in past

Stats

Popular Searches

Readme

Contents

What is this?

When should I use this?

Install

Use

API

`unified().use(remarkValidateLinks[, options])`

Parameters

Returns

`Options`

Fields

`UrlConfig`

Fields

Notes

Examples

Example: CLI

Example: CLI in npm scripts

Integration

Types

Compatibility

Security

Related

Contribute

License

remark-validate-links

Downloads in past1 Month3 Months6 Months1 Year2 Years5 YearsAll time

Stats

Popular Searches

Readme

Contents

What is this?

When should I use this?

Install

Use

API

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

Parameters

Returns

Options

Fields

UrlConfig

Fields

Notes

Examples

Example: CLI

Example: CLI in npm scripts

Integration

Types

Compatibility

Security

Related

Contribute

License

Sick of boring JavaScript newsletters?

Downloads in past

`unified().use(remarkValidateLinks[, options])`

`Options`

`UrlConfig`