Configure Node.js Rendering

Pass an options object to a render function, or set it once when constructing a Renderer. Use camelCase property names. Unknown keys throw a TypeError so spelling mistakes cannot silently change your output.

Enable the features your content uses

import { type Options, toHtml } from "ferromark";

const options = {
  frontMatter: true,
  headingIds: true,
  footnotes: true,
  tableColgroup: true,
  tableColumnNames: true,
  tableAttributes: true,
} satisfies Options;

const html = toHtml("# Notes\n\nA detail.[^1]\n\n[^1]: More context.", options);

Omitted values use the package defaults. There are no named preset constructors in the Node.js API; configure the individual options directly. To add bare URL and email detection to the default GFM extensions, set autolinkLiterals: true.

Option reference

All properties are optional. Syntax examples and output semantics live in the shared Markdown guide.

Option	Default	Purpose
`renderPolicy`	`'untrusted'`	Escape raw HTML and check URL schemes; `'trusted'` permits passthrough
`allowHtml`	`true`	Permit raw HTML in trusted output; false escapes it
`allowLinkRefs`	`true`	Resolve reference-style links
`tables`	`true`	GFM pipe tables
`mergedTableCells`	`false`	Horizontal cell spans; requires `tables`
`strikethrough`	`true`	Double-tilde strikethrough
`highlight`	`false`	Highlight markup
`superscript`	`false`	Superscript markup
`subscript`	`false`	Subscript markup
`taskLists`	`true`	Task-list checkboxes
`autolinkLiterals`	`false`	Bare URL, www, and email links
`disallowedRawHtml`	`true`	GFM tag filter in trusted mode
`footnotes`	`false`	Reference footnotes
`inlineFootnotes`	`false`	Inline footnotes
`frontMatter`	`false`	Extract leading YAML/TOML-style front matter
`headingIds`	`true`	Generate heading IDs
`math`	`false`	Inline and display math markup
`callouts`	`true`	GitHub-style note/warning callouts
`definitionLists`	`false`	Terms and descriptions
`lineComments`	`false`	Omit physical-line-start source comments
`linkBasePath`	unset	Enable site routing for links, images, raw HTML URLs, and .md paths
`tableAttributes`	`false`	Table IDs, CSS classes, and captions
`tableColgroup`	`false`	CSS-addressable colgroup elements
`tableColumnNames`	`false`	Header-derived column classes; requires tableColgroup
`headingAttributes`	`false`	Explicit heading IDs and classes
`wikiLinks`	`false`	Wiki-link syntax
`cjkEmphasis`	`false`	CJK emphasis rules
`mdx`	`false`	MDX syntax capture and static island output

The published TypeScript declarations are the complete API contract and power editor autocomplete.

Preserve trusted HTML

import { toHtml } from "ferromark";

const html = toHtml('<span class="note">Internal note</span>', {
  renderPolicy: "trusted",
});

Use this only for content you trust. It also permits arbitrary URL schemes. The default disallowedRawHtml filter still removes GFM-disallowed tags; it is not an HTML sanitizer. See rendering and trust.

Next: HTML, metadata, and reusable renderers.