Code highlighting

The default compiler can render code with Shiki. A custom highlightCode function can return trusted highlighted HTML for each block while preserving the original value, language, metadata, and source path.

const highlightCode = async ({ value, language }) => {
  if (language !== 'ts') return undefined
  return highlightTypeScript(value)
}

Returning undefined falls back to the standard highlighter. The original code always remains available for copy controls, Markdown output, search, and tests.

Twoslash

Use @foldocs/twoslash for compiler-powered TypeScript hover information. Keep it opt-in for explicit blocks so ordinary snippets stay fast to build.

Trusted markup

Highlighters run during compilation. Their HTML is stored separately from the original source, which remains the value used by copy controls and serializers.

Failure fallback

Unknown grammars and highlighter errors fall back to escaped plain code rather than preventing the rest of the documentation corpus from building.