eslint-mdx

ESLint Parser/Plugin for MDX, helps you lint all ES syntaxes. Linting code blocks can be enabled with mdx/code-blocks setting too! Work perfectly with eslint-plugin-import, eslint-plugin-prettier or any other eslint plugins. And also can be integrated with remark-lint plugins to lint markdown syntaxes.

TOC

• VSCode Extension
• Packages
• Install
• Notice
• Usage
  • Classic Config
  • Flat Config
• Parser Options
• Parser API
  • MDXCode
  • MDXHeading
  • Typings
• Rules
  • mdx/remark
• Prettier Integration
• Sponsors and Backers
  • Sponsors
  • Backers
• Changelog
• License

VSCode Extension

VSCode MDX: Integrates with VSCode ESLint, syntaxes highlighting and error reporting.

Packages

This repository is a monorepo managed by changesets what means we actually publish several packages to npm from same codebase, including:

Package	Description	Version
eslint-mdx	ESLint Parser for MDX
eslint-plugin-mdx	ESLint Plugin, Configuration and Rules for MDX

Install

# yarn
yarn add -D eslint-plugin-mdx

# npm
npm i -D eslint-plugin-mdx

Notice

• If you're using multi languages, js/jsx/ts/tsx/vue, etc for example, you'd better to always use overrides (Classic Config) or files (Flag Config) feature of ESLint, because configs may be overridden by following configs.

  See #251 for more details.

• If you're using {/* eslint-disable-line mdx/remark */} with prettier, this won't work because prettier will add a blank line after the comment, which makes it invalid. You can use {/* eslint-disable mdx/remark */} paired with {/* eslint-enable mdx/remark */} instead:

  {/* eslint-disable mdx/remark */}
  
  # Heading
  
  {/* eslint-enable mdx/remark */}
  

Usage

Classic Config

.eslintrc file:

{
  "extends": ["plugin:mdx/recommended"],
  // optional, if you want to lint code blocks at the same time
  "settings": {
    "mdx/code-blocks": true,
    // optional, if you want to disable language mapper, set it to `false`
    // if you want to override the default language mapper inside, you can provide your own
    "mdx/language-mapper": {},
    // optional, same as the `parserOptions.ignoreRemarkConfig`, you have to specify it twice unfortunately
    "mdx/ignore-remark-config": true,
    // optional, same as the `parserOptions.remarkConfigPath`, you have to specify it twice unfortunately
    "mdx/remark-config-path": "path/to/your/remarkrc",
  },
}

Flat Config

eslint.config.js file:

import * as mdx from 'eslint-plugin-mdx'

export default [
  {
    ...mdx.flat,
    // optional, if you want to lint code blocks at the same
    processor: mdx.createRemarkProcessor({
      lintCodeBlocks: true,
      // optional, if you want to disable language mapper, set it to `false`
      // if you want to override the default language mapper inside, you can provide your own
      languageMapper: {},
      // optional, same as the `parserOptions.ignoreRemarkConfig`, you have to specify it twice unfortunately
      ignoreRemarkConfig: true,
      // optional, same as the `parserOptions.remarkConfigPath`, you have to specify it twice unfortunately
      remarkConfigPath: 'path/to/your/remarkrc',
    }),
  },
  {
    ...mdx.flatCodeBlocks,
    rules: {
      ...mdx.flatCodeBlocks.rules,
      // if you want to override some rules for code blocks
      'no-var': 'error',
      'prefer-const': 'error',
    },
  },
]

Then, make sure ESLint knows to run on .md or .mdx files:

eslint . --ext js,md,mdx

Parser Options

• extensions (string | string[]): eslint-mdx will only resolve .mdx files by default, if you want to resolve other extensions as like .mdx, you can use this option.

• markdownExtensions (string | string[]): eslint-mdx will only treat .md files as plain markdown by default, and will lint them via remark plugins. If you want to resolve other extensions as like .md, you can use this option.

• ignoreRemarkConfig (boolean): Ignore the remark configuration defined in the project.

• remarkConfigPath (string): Specify the path to the remark configuration file, could be relative to CWD or absolute path.

Parser API

MDXCode

A new MDXCode estree node type is exported from eslint-mdx which represents code blocks in mdx like the following:

<div>
  ```js
  export function foo() {
    return 'bar'
  }
  ```
</div>

See also https://github.com/syntax-tree/mdast#code

MDXHeading

A new MDXHeading estree node type is exported from eslint-mdx which represents markdown heading in mdx like the following:

<div>
# Here's a text gradient short code!
</div>

See also https://github.com/syntax-tree/mdast#heading

Typings

import type { BaseNode } from 'estree'
import type { JSXElement } from 'estree-jsx'

export interface MDXCode extends BaseNode {
  type: 'MDXCode'
  value: string
  lang?: string | null
  meta?: string | null
}

export type HeadingDepth = 1 | 2 | 3 | 4 | 5 | 6

export interface MDXHeading extends BaseNode {
  type: 'MDXHeading'
  depth: HeadingDepth
  children: JSXElement['children']
}

Rules

mdx/remark

possible fixable depends on your remark plugins:

Integration with remark-lint plugins, it will read remark's configuration automatically via unified-engine. But .remarkignore will not be respected, you should use .eslintignore instead.

If you want to disable or change severity of some related rules, it won't work by setting rules in eslint config like 'remark-lint-no-duplicate-headings': 0, you should change your remark config instead like following:

{
  "plugins": [
    "@1stg/remark-config",
    // change to error severity, notice `[]` is required
    ["lint-no-duplicate-headings", [2]],
    // disable following plugin
    [
      "lint-no-multiple-toplevel-headings",
      [0], // or false
    ],
  ],
}

Prettier Integration

If you're using remark-lint feature with Prettier both together, you can try remark-preset-prettier which helps you to turn off all rules that are unnecessary or might conflict with Prettier.

{
  "plugins": [
    "preset-lint-consistent",
    "preset-lint-recommended",
    "preset-lint-markdown-style-guide",
    "preset-prettier"
  ]
}

Sponsors and Backers

Sponsors

1stG	RxTS	UnRS	UnTS

Backers

1stG	RxTS	UnRS	UnTS

Changelog

Detailed changes for each release are documented in CHANGELOG.md.

License

MIT © [e-mail]

Similar packages

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eslint-plugin-markdown

eslint-plugin-markdown is an ESLint plugin that allows linting of JavaScript code blocks within Markdown files. Unlike eslint-mdx, which is specifically designed for MDX files, eslint-plugin-markdown focuses on JavaScript code within standard Markdown files.

remark-lint

remark-lint is a plugin for remark, a Markdown processor, that provides linting capabilities for Markdown files. While eslint-mdx leverages ESLint for linting MDX files, remark-lint is part of the remark ecosystem and focuses on Markdown linting with its own set of rules and plugins.

eslint-plugin-react

eslint-plugin-react is an ESLint plugin that provides linting rules for React applications. Although it is not specifically designed for MDX files, it can be used in conjunction with eslint-mdx to ensure React code within MDX files adheres to best practices.