@rendermark/core

Markdown rendering engine — convert Markdown to beautiful HTML documents, PDFs, DOCX, slides, and more.

Installation

npm install @rendermark/core

Quick Start

import { renderMarkdownToHtml } from "@rendermark/core";

const html = await renderMarkdownToHtml({
  title: "My Document",
  markdown: "# Hello World\n\nThis is **RenderMark**.",
  theme: "default",
  showToc: true,
});

// html is a complete, styled HTML document ready to serve or save

API Reference

Rendering

renderMarkdownToHtml(options: RenderOptions): Promise<string>

Render markdown to a full, styled HTML document with CSS, fonts, branding, and table of contents.

const html = await renderMarkdownToHtml({
  title: "Report",
  markdown: content,
  showToc: true,
  theme: "serif",
  template: "report",
  github: { owner: "user", repo: "repo", branch: "main", path: "docs/file.md" },
  sanitize: true, // Strip XSS for public-facing pages
});

markdownToHtmlFragment(markdown: string): Promise<string>

Render markdown to an HTML fragment (no document wrapper). Useful for inline rendering or blog posts.

generateGoogleDocsHtml(title: string, markdown: string): Promise<string>

Generate simplified HTML optimized for Google Docs import, with inline styles and GDocs-compatible formatting.

markdownToDocx(options): Promise<Buffer>

Convert markdown to a DOCX (Word) file buffer.

import { markdownToDocx } from "@rendermark/core";

const buf = await markdownToDocx({
  markdown: content,
  title: "My Document",
  github: { owner: "user", repo: "repo", path: "doc.md" },
});

renderToImage(options: RenderToImageOptions): Promise<void>

Render markdown to a PNG or JPEG screenshot via a callback. Requires a Puppeteer-compatible environment.

renderDiff(options: DiffOptions): string

Generate a visual diff between two markdown versions as a standalone HTML document.

import { renderDiff } from "@rendermark/core";

const html = renderDiff({
  before: oldMarkdown,
  after: newMarkdown,
  mode: "inline", // or "side-by-side"
  title: "Document Changes",
});

markdownToSlides(options: SlideOptions): Promise<string>

Convert markdown into a presentation slide deck. Slides split on --- (horizontal rules) or ## headings.

import { markdownToSlides } from "@rendermark/core";

const html = await markdownToSlides({
  markdown: content,
  title: "My Presentation",
  theme: "dark",
  splitOn: "hr", // or "h2"
});

Frontmatter

parseFrontmatter(markdown: string): { data: FrontmatterData; content: string }

Parse YAML frontmatter from a markdown string. Returns the parsed data and the content without frontmatter.

Themes

getTheme(name: string): string

Get the CSS override for a named theme. Returns an empty string for unknown themes.

listThemes(): string[]

List all available built-in theme names.

isBuiltinTheme(name: string): boolean

Check if a theme name is a built-in theme.

Templates

applyTemplate(name: string, options): string

Apply a named template to markdown content. Templates wrap the markdown with structural elements.

listTemplates(): string[]

List all available built-in template names.

getTemplateDefaultTheme(name: string): string | undefined

Get the default theme associated with a template.

Utilities

resolveGitHubRelativePaths(markdown: string, context?: GitHubContext): string

Resolve relative image/link paths in markdown to absolute GitHub raw URLs.

extractHeadings(markdown: string): TocItem[]

Extract headings (h1–h3) from raw markdown for table of contents generation.

generateTocHtml(headings: TocItem[]): string

Generate an HTML table of contents from extracted headings.

generateSlug(text: string): string

Generate a URL-safe slug from heading text, matching GitHub/rehype-slug conventions.

escapeHtml(str: string): string

HTML-escape a string (&, <, >, ", ').

Unified Pipelines

createProcessor()

Create the full unified processor with all remark/rehype plugins (GFM, math, syntax highlighting, mermaid, callouts, etc.).

createBasicProcessor()

Create a basic processor without syntax highlighting or advanced plugins. Used for Google Docs output.

createSanitizedProcessor()

Create a sanitized processor that strips XSS vectors while preserving classes/ids for styling.

Plugins

These remark/rehype plugins are used internally and exported for advanced usage:

• remarkMermaid — Transform mermaid code blocks into client-side rendered diagrams
• remarkCallouts — Obsidian-style > [!note] callout boxes
• remarkWikiLinks — [[slug]] and [[slug|text]] wiki-style links
• remarkComments — Strip %%hidden%% Obsidian-style comments
• rehypeSourceLines — Add data-source-line attributes for scroll sync

RenderOptions

interface RenderOptions {
  title: string;
  markdown: string;
  showToc?: boolean;        // Include table of contents (default: true)
  github?: GitHubContext;   // GitHub context for resolving relative paths
  docId?: string;           // Document ID for branding links
  theme?: string;           // Theme name
  template?: string;        // Template name
  sanitize?: boolean;       // Use sanitized processor for public pages
}

Themes

| Theme | Description | |-----------|---------------------------------------| | default | Clean, modern with Geist font | | dark | Dark background, light text | | serif | Traditional serif typography | | minimal | Stripped-down, distraction-free |

Themes can be set via the theme option or theme frontmatter field.

Templates

| Template | Description | Default Theme | |-----------------|------------------------------------|---------------| | report | Formal report with cover page | — | | meeting-notes | Meeting notes with attendees | — | | memo | Internal memo format | — | | letter | Formal letter layout | serif | | slides | Presentation slide deck | — | | changelog | Version changelog format | — |

Templates can be set via the template option or template frontmatter field.

Frontmatter

RenderMark supports YAML frontmatter at the top of markdown files:

---
title: My Document
theme: serif
template: report
toc: true
author: Jane Doe
date: 2025-01-15
custom_field: any value
---

Supported Fields

| Field | Type | Description | |------------|---------|------------------------------------------| | title | string | Document title | | theme | string | Theme name (default, dark, serif, minimal)| | template | string | Template name | | toc | boolean | Show table of contents | | author | string | Author name (used by templates) | | date | string | Date (used by templates) |

Additional custom fields are passed through and available to templates.

License

MIT