• Created:2026/02/09
• Updated:2026/02/09
• Author:
  Takeshi Takatsudo

Configuration

The formatter looks for configuration in three layers (later layers override earlier ones):

1. Built-in defaults (from settings.mjs)
2. Config file (.mdx-formatter.json or "mdx-formatter" key in package.json)
3. Programmatic options (passed to format())

Config File

Create .mdx-formatter.json in your project root:

{
  "addEmptyLinesInBlockJsx": {
    "blockComponents": ["Outro", "InfoBox"]
  },
  "indentJsxContent": {
    "containerComponents": ["Outro", "InfoBox", "LayoutDivide"]
  },
  "formatMultiLineJsx": {
    "ignoreComponents": ["CodeBlock"]
  }
}

Or add an "mdx-formatter" key to your package.json:

{
  "mdx-formatter": {
    "addEmptyLinesInBlockJsx": {
      "blockComponents": ["Outro", "InfoBox"]
    }
  }
}

Excluding Files

You can add an exclude array to your config file to skip files matching the given glob patterns. These patterns are merged with the CLI --ignore option.

{
  "exclude": ["doc/docs/claude/**", "generated/**/*.md"],
  "formatMultiLineJsx": {
    "ignoreComponents": ["CodeBlock"]
  }
}

This is useful for excluding auto-generated files that don't need formatting, without adding patterns to every CLI invocation.

The exclude key also works in package.json:

{
  "mdx-formatter": {
    "exclude": ["doc/docs/claude/**"]
  }
}