Extended AST Node Specifications

The standard Markdown Abstract Syntax Tree (MDAST) specified by syntax-tree/mdast was originally designed for HTML serialization. Because Microsoft Word OpenXML enforces richer document models (drawingml, tables with block children, vector drawings, checkboxes), @m2d/mdast augments the standard node definitions.

Specialized Node TypesCopy Anchor Link

1. SVG (type: "svg")Copy Anchor Link

Represents vector graphics, diagrams, or charts awaiting rasterization or conversion into OpenXML drawings:

export interface SVGData extends Data {
  /** Original Mermaid diagram source code for fallback rendering */
  mermaid?: string;
}

export interface SVG extends Node {
  type: "svg";
  value: string | Promise<RenderResult | undefined>;
  data?: SVGData;
}

2. Checkbox (type: "checkbox")Copy Anchor Link

Represents interactive or rendered task checkboxes derived from GFM task lists (- [x]) or HTML <input type="checkbox"> elements:

export interface Checkbox extends Node {
  type: "checkbox";
  checked?: boolean;
}

3. Fragment (type: "fragment")Copy Anchor Link

Represents a grouping container that holds multiple block or phrasing nodes without generating extraneous wrapper paragraphs in the target document:

export interface Fragment extends Parent {
  type: "fragment";
  children: (RootContent | PhrasingContent)[];
}

Augmented Standard NodesCopy Anchor Link

Block Content in Table Cells (TableCell)Copy Anchor Link

In standard MDAST, TableCell.children only permits PhrasingContent[] (inline text). To accommodate advanced HTML tables and multi-paragraph cells, @m2d/mdast widens the cell model:

export interface TableCell extends Parent {
  type: "tableCell";
  /** Allows rich block nodes (paragraphs, lists, code, quotes) inside cells */
  children: RootContent[];
  data?: TableCellData;
}

Word Formatting Payloads in node.dataCopy Anchor Link

Plugins attach Microsoft Word styling properties directly to node.data:

• Paragraph-level properties (alignment, spacing, indent, borders)
• Run-level properties (font, size, color, bold, italics, highlight)
• Image layout options (width, height, floating, wrap)