remark-lint-no-duplicate-headings
remark-lint
rule to warn when headings with the same text are found.
Contents
- What is this?
- When should I use this?
- Presets
- Install
- Use
- API
- 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 headings with the same text are used once.
Presets
This rule is included in the following presets:
Preset | Setting |
---|---|
remark-preset-lint-markdown-style-guide |
Install
This package is ESM only. In Node.js (version 12.20+, 14.14+, or 16.0+), install with npm:
npm install remark-lint-no-duplicate-headings
In Deno with esm.sh
:
import remarkLintNoDuplicateHeadings from 'https://esm.sh/remark-lint-no-duplicate-headings@3'
In browsers with esm.sh
:
<script type="module">
import remarkLintNoDuplicateHeadings from 'https://esm.sh/remark-lint-no-duplicate-headings@3?bundle'
</script>
Use
On the API:
import {remark} from 'remark'
import remarkLint from 'remark-lint'
import remarkLintNoDuplicateHeadings from 'remark-lint-no-duplicate-headings'
import {read} from 'to-vfile'
import {reporter} from 'vfile-reporter'
const file = await read('example.md')
await remark()
.use(remarkLint)
.use(remarkLintNoDuplicateHeadings)
.process(file)
console.error(reporter(file))
On the CLI:
remark --use remark-lint --use remark-lint-no-duplicate-headings example.md
On the CLI in a config file (here a package.json
):
…
"remarkConfig": {
"plugins": [
…
"remark-lint",
+ "remark-lint-no-duplicate-headings",
…
]
}
…
API
This package exports no identifiers. The default export is remarkLintNoDuplicateHeadings
.
unified().use(remarkLintNoDuplicateHeadings[, 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).
There are no options.
Recommendation
Headings having unique text helps screen reader users (who typically use “jump to heading” features to navigate within a page, which reads headings out loud). It also helps because often headings receive automatic unique IDs, and when the same heading text is used, they are suffixed with a number based on where they are positioned in the document, which makes linking to them prone to changes.
Examples
ok.md
In
# Foo
## Bar
Out
No messages.
not-ok.md
In
# Foo
## Foo
## [Foo](http://foo.com/bar)
Out
3:1-3:7: Do not use headings with similar content (1:1)
5:1-5:29: Do not use headings with similar content (3:1)
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.