@guren/plugin-markdown

Markdown-to-HTML rendering for Guren applications: GitHub Flavored Markdown, sanitized output by default, GitHub-style alerts, heading anchors, and optional shiki code highlighting (RFC 0012).

bunx guren plugin @guren/plugin-markdown
bun add @guren/plugin-markdown

Rendering

import { createMarkdownRenderer } from '@guren/plugin-markdown'

const renderer = createMarkdownRenderer()
const html = await renderer.render('# Hello\n\n> [!NOTE]\n> Sanitized by default.')

render() is a pure async function — render at save time and store the HTML, or render per request; the package has no cache and no opinion.

Defaults (all overridable):

• sanitize: true — output passes a sanitize-html allowlist tuned for markdown plus shiki's inline styles: javascript:/data:/protocol-relative URLs are dropped, raw HTML is escaped, only shiki-shaped style declarations survive. The rendered HTML is safe to inject with dangerouslySetInnerHTML. Pass false for trusted content, or a callback to extend the allowlist:

  createMarkdownRenderer({
    sanitize: (defaults) => ({
      ...defaults,
      allowedTags: [...(defaults.allowedTags as string[]), 'video'],
    }),
  })

• alerts: true — > [!NOTE] / [!TIP] / [!IMPORTANT] / [!WARNING] / [!CAUTION] blockquotes become labeled alert blocks with guren-markdown-alert class names.

• anchors: true — headings get slug ids (unicode-aware, duplicate-safe, hardened against HTML smuggled into heading text).

• rewriteLink — hook over every link href, e.g. rewriting relative .md links to routes.

• highlight — code-fence highlighter, (code, lang) => string | Promise<string>.

Shiki highlighting

shiki is an optional peer dependency behind its own subpath — install it only if you use it:

bun add shiki

import { createMarkdownRenderer } from '@guren/plugin-markdown'
import { createShikiHighlight } from '@guren/plugin-markdown/shiki'

const renderer = createMarkdownRenderer({
  highlight: createShikiHighlight({
    themes: { light: 'rose-pine-dawn', dark: 'rose-pine-moon' },
    langs: ['typescript', 'tsx', 'bash', 'json'],
  }),
})

This builds a fine-grained shiki/core highlighter (only the listed grammars, JavaScript regex engine — no oniguruma WASM) and emits dual-theme output: the light palette inline, the dark palette in --shiki-dark custom properties. Fences in unloaded languages fall back to plain text.

Bundlers that must see every import statically (Cloudflare Workers builds) should pass explicit modules instead of names:

createShikiHighlight({
  themes: { light: 'rose-pine-dawn', dark: 'rose-pine-moon' },
  themeModules: [
    import('shiki/dist/themes/rose-pine-dawn.mjs'),
    import('shiki/dist/themes/rose-pine-moon.mjs'),
  ],
  langModules: [import('shiki/dist/langs/typescript.mjs')],
})

Styling

The renderer emits class names but no styles. A small reference stylesheet covers alerts and the dark-mode shiki toggle:

import '@guren/plugin-markdown/styles.css'

As a plugin

import { markdownPlugin } from '@guren/plugin-markdown'

createApp({
  providers: [markdownPlugin({ /* renderer options */ })],
})

The provider binds the configured renderer as the markdown container service:

import type { MarkdownRenderer } from '@guren/plugin-markdown'

const renderer = container.make<MarkdownRenderer>('markdown')