📄 @aidalinfo/office-to-markdown

A modern TypeScript library for converting Office documents (DOCX) to Markdown format, optimized for the Bun ecosystem with advanced support for mathematical equations and tables.

🔬 Created through reverse engineering of Microsoft's MarkItDown - A TypeScript reimplementation that brings Python's document conversion capabilities to the JavaScript/Bun ecosystem with enhanced performance and type safety.

🚀 Features

• ✅ DOCX to Markdown conversion with structure preservation
• ✅ Mathematical equation support (OMML → LaTeX)
• ✅ Table handling with automatic formatting
• ✅ Style preservation (bold, italic, headings)
• ✅ Image processing with alt text
• ✅ Simple and advanced API for different use cases
• ✅ Robust error handling with specific error codes
• ✅ Optimized performance with Bun runtime
• ✅ Complete TypeScript types for better DX

📦 Installation

With Bun (recommended)

bun add @aidalinfo/office-to-markdown

With npm/yarn/pnpm

npm install @aidalinfo/office-to-markdown
# or
yarn add @aidalinfo/office-to-markdown
# or  
pnpm add @aidalinfo/office-to-markdown

Required Dependencies

The following dependencies are automatically installed:

• mammoth - DOCX to HTML conversion
• turndown - HTML to Markdown conversion
• jszip - ZIP archive manipulation (DOCX)

🛠️ Conversion Workflow

The conversion process follows these steps:

1. File Detection - MIME type and extension verification
2. Preprocessing - DOCX content extraction and modification
3. Math Processing - OMML → LaTeX conversion
4. Main Conversion - DOCX → HTML via mammoth
5. Post-processing - HTML → Markdown with custom rules

🎯 Simple Usage

Basic Conversion

import { docxToMarkdown } from '@aidalinfo/office-to-markdown';

// Simple file conversion
const markdown = await docxToMarkdown('./document.docx');
console.log(markdown);

Advanced API

import { OfficeToMarkdown } from '@aidalinfo/office-to-markdown';

const converter = new OfficeToMarkdown({
  headingStyle: 'atx',           // Use ## for headings
  preserveTables: true,          // Preserve tables
  convertMath: true,             // Convert equations to LaTeX
});

// Conversion with options
const result = await converter.convertDocx('./document.docx');
console.log('Title:', result.title);
console.log('Content:', result.markdown);

Conversion from Different Sources

import { OfficeToMarkdown } from '@aidalinfo/office-to-markdown';

const converter = new OfficeToMarkdown();

// From file path
const result1 = await converter.convert('./document.docx');

// From Buffer
const buffer = await Bun.file('./document.docx').arrayBuffer();
const result2 = await converter.convert(buffer);

// From Bun file
const file = Bun.file('./document.docx');
const result3 = await converter.convert(file);

// Batch processing
const results = await converter.convertMultiple([
  './doc1.docx',
  './doc2.docx',
  buffer
]);

⚙️ Configuration Options

| Option | Type | Default | Description | |--------|------|---------|-------------| | headingStyle | 'atx' \| 'setext' | 'atx' | Markdown heading style | | preserveTables | boolean | true | Preserve tables | | convertMath | boolean | true | Convert mathematical equations | | styleMap | string | - | Custom mapping for mammoth |

🔧 Technical Architecture

Module Structure

src/
├── converters/           # Document converters
│   ├── base-converter.ts    # Abstract base class
│   └── docx-converter.ts    # Specialized DOCX converter
├── preprocessing/        # Preliminary processing
│   └── docx-preprocessor.ts # DOCX preprocessing (math)
├── math/                # Mathematical processing
│   └── omml-processor.ts    # OMML → LaTeX converter
├── utils/               # Utilities
│   ├── html-to-markdown.ts # HTML → Markdown conversion
│   ├── file-detector.ts     # File type detection
│   └── error-handler.ts     # Error handling
└── types/               # TypeScript definitions
    ├── converter.ts         # Converter types
    ├── result.ts           # Result types
    └── stream-info.ts      # File info types

Conversion Pipeline

1. File Detection - MIME type and extension verification
2. Preprocessing - DOCX content extraction and modification
3. Mathematical Processing - OMML → LaTeX conversion
4. Main Conversion - DOCX → HTML via mammoth
5. Post-processing - HTML → Markdown with custom rules

Mathematical Equation Handling

The equation conversion follows this process:

// OMML (Office Math Markup Language)
<m:f>
  <m:num>1</m:num>
  <m:den>2</m:den>
</m:f>

// ↓ Preprocessing

<w:r><w:t>$\frac{1}{2}$</w:t></w:r>

// ↓ Mammoth (HTML)

<p>$\frac{1}{2}$</p>

// ↓ Turndown (Markdown)

$\frac{1}{2}$

Supported Mathematical Elements

| OMML | LaTeX | Description | |------|-------|-------------| | <m:f> | \frac{}{} | Fractions | | <m:sSup> | ^{} | Exponents | | <m:sSub> | _{} | Subscripts | | <m:rad> | \sqrt{} | Square roots | | <m:rad><m:deg> | \sqrt[]{} | Nth roots |

🎨 Advanced Usage Examples

Error Handling

import { 
  OfficeToMarkdown, 
  FileConversionException, 
  UnsupportedFormatException 
} from '@aidalinfo/office-to-markdown';

async function convertSafely(filePath: string) {
  try {
    const converter = new OfficeToMarkdown();
    const result = await converter.convertDocx(filePath);
    return result.markdown;
  } catch (error) {
    if (error instanceof UnsupportedFormatException) {
      console.error('Unsupported format:', error.message);
    } else if (error instanceof FileConversionException) {
      console.error('Conversion error:', error.message);
    } else {
      console.error('Unexpected error:', error.message);
    }
    throw error;
  }
}

Capability Checking

import { OfficeToMarkdown } from '@aidalinfo/office-to-markdown';

const converter = new OfficeToMarkdown();

// Check supported types
const info = converter.getSupportedTypes();
console.log('Extensions:', info.extensions); // ['.docx']
console.log('MIME types:', info.mimeTypes);

// Check if a file is supported
const isSupported = await converter.isSupported('./document.pdf');
console.log('PDF supported:', isSupported); // false

// Get file information
const fileInfo = await converter.getFileInfo('./document.docx');
console.log('MIME type:', fileInfo.mimetype);
console.log('Supported:', fileInfo.supported);

Usage with Node.js

import { readFile } from 'fs/promises';
import { OfficeToMarkdown } from '@aidalinfo/office-to-markdown';

// From Node.js Buffer
const buffer = await readFile('./document.docx');
const converter = new OfficeToMarkdown();
const result = await converter.convert(buffer);

console.log(result.markdown);

🧪 Testing and Validation

Test Results

• ✅ HTML → Markdown conversion with tables
• ✅ File type detection (DOCX vs others)
• ✅ OMML → LaTeX mathematical conversion
• ✅ Error handling with specific codes
• ✅ Complete pipeline tested with real documents

Performance

• Speed: ~80ms for an average document (7KB)
• Fidelity: Complete preservation of structure and content
• Robustness: Graceful error handling with fallbacks

🔧 Development

Prerequisites

• Bun >= 1.2.0 (recommended) or Node.js >= 20.0.0
• TypeScript >= 4.5.0

Development Installation

git clone https://github.com/aidalinfo/extract-kit.git
cd extract-kit/packages/office-to-markdown
bun install

Available Scripts

bun run build          # Complete build (ESM + types)
bun run dev            # Development mode with watch
bun run clean          # Clean dist/ folder

Testing

# Basic functionality test
bun run src/test.ts

# Test with real DOCX file
bun run test-docx.ts "your-file.docx"

🚀 Roadmap

• [ ] PPT/PPTX format support - Presentation conversion
• [ ] XLS/XLSX format support - Spreadsheet conversion
• [ ] Streaming API - Large file streaming processing
• [ ] Plugin system - Support for custom converters
• [ ] Web interface - Optional user interface
• [ ] Embedded image support - Image extraction and conversion
• [ ] CLI batch mode - Command-line interface

🤝 Contributing

Contributions are welcome! Please see our contribution guide.

Contribution Process

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

📄 License

This project is licensed under MIT - see the LICENSE file for details.

🙏 Acknowledgments

• Inspired by Microsoft's MarkItDown project
• Uses mammoth.js for DOCX → HTML conversion
• Uses turndown for HTML → Markdown conversion
• Optimized for Bun runtime

📞 Support

• Issues: GitHub Issues
• Documentation: GitHub Repository
• Email: [email protected]

@aidalinfo/office-to-markdown

Simple, fast, and reliable DOCX to Markdown conversion ⚡