mdx-js / 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
• Parser Options
• Rules
  • mdx/no-jsx-html-comments
  • mdx/no-unused-expressions
  • mdx/remark
• Prettier Integration
• Changelog
• License

VSCode Extension

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

Packages

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

Package	Description	Version	Peer Dependencies	Dependencies
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 feature of ESLint, because configs may be overridden by following configs.

See #251 for more details.

Usage

1. In your ESLint config file:

   1. If you're using eslint >= 6.4.0, just add:

      {
        "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": {}
        }
      }
      

   2. If you're using eslint >=6.0.0 and <6.4.0, add as following because it does not support overrides from npm pkg:

      {
        "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": {}
        },
        "overrides": [
          {
            "files": ["*.md"],
            "rules": {
              "prettier/prettier": [
                2,
                {
                  // unnecessary if you're not using `eslint-plugin-prettier`, but required if you are
                  "parser": "markdown"
                }
              ]
            }
          },
          {
            "files": ["*.mdx"],
            "extends": ["plugin:mdx/overrides"]
          },
          {
            "files": "**/*.{md,mdx}/**",
            "extends": "plugin:mdx/code-blocks"
          }
        ]
      }
      

   3. If you're using [email protected]^5.0.0, you need to enable this parser/plugin manually, because [email protected] does not support extends for overrides property in its configuration:

      const { configs } = require('eslint-plugin-mdx')
      
      module.exports = {
        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': {},
        },
        overrides: [
          {
            files: ['*.md'],
            rules: {
              'prettier/prettier': [
                2,
                {
                  // unnecessary if you're not using `eslint-plugin-prettier`, but required if you are
                  parser: 'markdown',
                },
              ],
            },
          },
          {
            files: ['*.mdx'],
            ...configs.overrides,
          },
          {
            files: '**/*.{md,mdx}/**',
            ...configs.codeBlocks,
          },
        ],
      }
      

2. Make sure ESLint knows to run on .md or .mdx files:

   eslint . --ext js,md,mdx
   

Parser Options

1. parser (string | ParserConfig | ParserFn): Custom parser for ES syntax is supported, although @typescript-eslint/parser or @babel/eslint-parser or babel-eslint will be detected automatically what means you actually do not need to do this:

   {
     "extends": ["plugin:mdx/recommended"],
     "parserOptions": {
       "parser": "babel-eslint"
     }
   }
   

2. extensions (string | string[]): eslint-mdx will only resolve .mdx files by default, files with other extensions will be resolved by the parser option. If you want to resolve other extensions as like .mdx, you can use this option.

3. 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.

Rules

mdx/no-jsx-html-comments

Fixable: HTML style comments in jsx block is invalid, this rule will help you to fix it by transforming it to JSX style comments.

mdx/no-unused-expressions

MDX can render jsx block automatically without exporting them, but ESLint will report no-unused-expressions issue which could be unexpected, this rule is the replacement, so make sure that you've turned off the original no-unused-expressions rule.

mdx/remark

possible fixable depends on your remark plugins:

Integration with remark-lint plugins, it will read remark's configuration automatically via cosmiconfig. 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"
  ]
}

Changelog

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

License

MIT © JounQin@1stG.me