markdownlint-custom-rules

Custom markdownlint rules require a rule object with names, description, tags, parser, and function properties. Define the function to inspect parsed markdown tokens and report errors using onError callbacks with optional fixInfo to suggest corrections.

Yes, markdownlint custom rules support markdown-it, micromark, or no parser. Choose based on your analysis depth: markdown-it and micromark provide token-level detail for complex rule logic, while none works for simpler pattern matching.

Report errors using onError callbacks that pass line number and error details. Include fixInfo objects to provide automated fix suggestions, enabling markdownlint to offer corrections for violations your rule detects.

Synchronous rules execute immediately and return results inline. Asynchronous rules handle operations like external API calls or file I/O by returning promises, letting markdownlint wait for completion before reporting errors.

Parser integration is optional but recommended for enforcing conventions beyond basic syntax. Using markdown-it or micromark gives access to token structures, enabling rules that enforce style, structure, and semantic patterns specific to your project.

Yes, the advanced rule structure supports detailed token analysis through markdown-it or micromark, enabling rules to enforce complex conventions like heading hierarchies, link validation, and content structure patterns across markdown documents.