remark-lint-definition-case

4.0.1 verified Fri May 01 auth: no javascript

A remark-lint rule that warns when definition labels in Markdown are not lowercase, helping enforce consistent casing. Current stable version is 4.0.1, published as part of the remark-lint monorepo. The plugin is ESM-only, supports Node.js 16+, and is compatible with remark-lint presets like remark-preset-lint-markdown-style-guide. It works with regular definitions and GFM footnote definitions. No options are required.

Common errors

error Cannot find module 'remark-lint-definition-case' ↓

cause Missing npm install or incorrect import path.

fix

Run 'npm install remark-lint-definition-case' and ensure import path is correct.

error remarkLintDefinitionCase is not a function ↓

cause Attempting to call the imported default export as a factory (e.g., remarkLintDefinitionCase()).

fix

Use the import directly: .use(remarkLintDefinitionCase), not .use(remarkLintDefinitionCase()).

Warnings

breaking v4.0.0: Package became ESM-only; removed CommonJS support. ↓

fix Use import syntax instead of require(). Ensure Node.js version 16+.

gotcha The rule checks definition labels (e.g., [label]: url) but does not affect reference labels (e.g., [label]) which are matched case-insensitively. ↓

fix No action needed; this is by design. Ensure definition labels are lowercase to avoid warnings.

gotcha The rule does not accept any options; passing options will be ignored silently. ↓

fix Do not pass options to the plugin.

Install

npm install remark-lint-definition-case

yarn add remark-lint-definition-case

pnpm add remark-lint-definition-case

Imports

remarkLintDefinitionCase

wrong

const remarkLintDefinitionCase = require('remark-lint-definition-case')

correct

import remarkLintDefinitionCase from 'remark-lint-definition-case'

ESM-only since v4; CJS require will throw an error.

default export

wrong

import { remarkLintDefinitionCase } from 'remark-lint-definition-case'

correct

import remarkLintDefinitionCase from 'remark-lint-definition-case'

The package has a default export, not a named export.

unified .use()
wrong
```
.use(remarkLintDefinitionCase())
```
correct
```
.use(remarkLintDefinitionCase)
```
The rule is a plugin function, not a factory; do not call it.

Quickstart

Shows how to use remark-lint-definition-case in a unified pipeline to lint a Markdown file and output messages.

import { read } from 'to-vfile'
import { reporter } from 'vfile-reporter'
import { unified } from 'unified'
import remarkParse from 'remark-parse'
import remarkStringify from 'remark-stringify'
import remarkLint from 'remark-lint'
import remarkLintDefinitionCase from 'remark-lint-definition-case'

const file = await read('example.md')

await unified()
  .use(remarkParse)
  .use(remarkLint)
  .use(remarkLintDefinitionCase)
  .use(remarkStringify)
  .process(file)

console.error(reporter(file))