excel-bridge

A powerful, lightweight Excel manipulation library built with TypeScript and micro-packages. Features advanced styling, multi-sheet support, formulas, and more - all with zero heavy dependencies.

✨ Advanced Features

• 🚀 High Performance - Built with fflate and fast-xml-parser for optimal speed
• 📦 Modular Architecture - Tree-shaking support with micro-packages
• 🔒 Full TypeScript - Complete type safety and IntelliSense
• 📖 Simple API - Intuitive interface for reading and writing Excel files
• 🎯 Cross-Platform - Works in both Browser and Node.js environments
• 🎨 Dynamic Styling - Advanced StyleManager with colors, fonts, borders
• 📊 Multi-Sheet Support - Create workbooks with multiple named sheets
• 🧮 Formula Support - Native Excel formulas (=SUM, =TODAY, custom formulas)
• 📅 Date Handling - Automatic conversion to Excel serial dates
• 🔄 Merge Cells - Combine cells across ranges
• 🧊 Freeze Panes - Lock header rows/columns
• 📏 Auto-Width Columns - Automatic column width calculation
• ✅ Data Validation - Dropdown lists and validation rules
• 🔧 Zero Heavy Dependencies - No ExcelJS or SheetJS required

Installation

npm install excel-bridge
# or
yarn add excel-bridge
# or
pnpm add excel-bridge

Quick Start

Reading Excel Files

import { ExcelBridge } from 'excel-bridge';

// From File (Browser)
const file = document.querySelector('input[type="file"]').files[0];
const workbook = await ExcelBridge.readFromFile(file);

// From Buffer (Node)
import fs from 'fs';
const buffer = fs.readFileSync('data.xlsx');
const workbook = ExcelBridge.read(buffer);

console.log(workbook.sheets[0].data);

Writing Excel Files

import { ExcelBridge } from 'excel-bridge';

const data = [
  ['Name', 'Age', 'City'],
  ['John', 25, 'New York'],
  ['Jane', 30, 'Los Angeles']
];

// Create Excel Blob (Browser)
const blob = ExcelBridge.write(data);
const url = URL.createObjectURL(blob);

// Create Excel Buffer (Node)
const buffer = ExcelBridge.writeBuffer(data);
import fs from 'fs';
fs.writeFileSync('output.xlsx', buffer);

Advanced Multi-Sheet Example

import { ExcelWriter } from 'excel-bridge';

const writer = new ExcelWriter({ creator: 'My App' });

// Sheet 1: Sales data with styling and formulas
const salesSheet = {
  data: [
    ['Product', 'Price', 'Quantity', 'Total'],
    ['Laptop', 999.99, 5, '=B2*C2'],
    ['Mouse', 29.99, 20, '=B3*C3'],
    ['Keyboard', 79.99, 10, '=B4*C4']
  ],
  styles: {
    '0-0': { background: '#4472C4', bold: true, color: '#FFFFFF' },
    '0-1': { background: '#4472C4', bold: true, color: '#FFFFFF' },
    '0-2': { background: '#4472C4', bold: true, color: '#FFFFFF' },
    '0-3': { background: '#4472C4', bold: true, color: '#FFFFFF' },
  },
  options: {
    name: 'Sales Report',
    freezePane: { row: 1 },
    autoWidth: true
  }
};

// Sheet 2: Dates and calculations
const datesSheet = {
  data: [
    ['Event', 'Date', 'Days Until Today'],
    ['Launch', new Date(2024, 6, 15), '=TODAY()-B2'],
    ['Meeting', new Date(2024, 8, 20), '=TODAY()-B3'],
    ['Deadline', new Date(2024, 11, 31), '=TODAY()-B4']
  ],
  options: {
    name: 'Timeline',
    autoWidth: true
  }
};

// Create workbook with multiple sheets
const buffer = writer.createWorkbookBuffer([salesSheet, datesSheet]);
import fs from 'fs';
fs.writeFileSync('advanced-report.xlsx', buffer);

Advanced Usage

Dynamic Styling with StyleManager

import { ExcelWriter, StyleManager } from 'excel-bridge';

const writer = new ExcelWriter({ creator: 'My App' });

const sheet = {
  data: [
    ['Product', 'Price', 'Stock', 'Status'],
    ['Laptop', 999.99, 15, 'Available'],
    ['Mouse', 29.99, 5, 'Low Stock'],
    ['Keyboard', 79.99, 0, 'Out of Stock']
  ],
  styles: {
    // Header styling
    '0-0': { background: '#4472C4', bold: true, color: '#FFFFFF' },
    '0-1': { background: '#4472C4', bold: true, color: '#FFFFFF' },
    '0-2': { background: '#4472C4', bold: true, color: '#FFFFFF' },
    '0-3': { background: '#4472C4', bold: true, color: '#FFFFFF' },
    
    // Conditional styling
    '2-2': { background: '#FFC7CE', color: '#9C0006' }, // Low stock - red
    '3-3': { background: '#FFE6E6', color: '#C00000' }, // Out of stock
    '1-2': { background: '#E2EFDA', color: '#006100' },  // Good stock - green
  },
  options: {
    name: 'Inventory',
    freezePane: { row: 1 },
    autoWidth: true
  }
};

const buffer = writer.createWorkbookBuffer([sheet]);

Merge Cells & Advanced Layout

import { ExcelWriter } from 'excel-bridge';

const writer = new ExcelWriter();

const reportSheet = {
  data: [
    ['Q1 2024 Sales Report', '', '', ''],
    ['', '', '', ''],
    ['Product', 'January', 'February', 'March'],
    ['Laptops', 45000, 52000, 48000],
    ['Accessories', 12000, 15000, 13500],
    ['Software', 8000, 8500, 9000],
    ['', '', '', ''],
    ['TOTAL', '=SUM(B4:B6)', '=SUM(C4:C6)', '=SUM(D4:D6)']
  ],
  styles: {
    '0-0': { background: '#5B9BD5', bold: true, color: '#FFFFFF' },
    '7-0': { background: '#70AD47', bold: true, color: '#FFFFFF' },
    '7-1': { background: '#70AD47', bold: true, color: '#FFFFFF' },
    '7-2': { background: '#70AD47', bold: true, color: '#FFFFFF' },
    '7-3': { background: '#70AD47', bold: true, color: '#FFFFFF' },
  },
  mergeCells: ['A1:D1', 'A8:D8'], // Merge title and total rows
  options: {
    name: 'Quarterly Report',
    freezePane: { row: 3 },
    autoWidth: true
  }
};

const buffer = writer.createWorkbookBuffer([reportSheet]);

Date Handling & Excel Formulas

import { ExcelWriter } from 'excel-bridge';

const writer = new ExcelWriter();

const projectSheet = {
  data: [
    ['Task', 'Start Date', 'End Date', 'Duration', 'Status'],
    ['Design', new Date(2024, 0, 15), new Date(2024, 1, 20), '=C2-B2', 'Completed'],
    ['Development', new Date(2024, 1, 21), new Date(2024, 4, 30), '=C3-B3', 'In Progress'],
    ['Testing', new Date(2024, 5, 1), new Date(2024, 5, 15), '=C4-B4', 'Planned'],
    ['Deployment', new Date(2024, 5, 16), new Date(2024, 5, 20), '=C5-B5', 'Planned'],
    ['', '', '', '', ''],
    ['Project Duration', '', '', '=MAX(D2:D5)', ''],
    ['Tasks Completed', '', '', '=COUNTIF(E2:E5,"Completed")', '']
  ],
  options: {
    name: 'Project Timeline',
    freezePane: { row: 1 },
    autoWidth: true
  }
};

const buffer = writer.createWorkbookBuffer([projectSheet]);

Working with Coordinates

import { coordinateToIndex, indexToCoordinate } from 'excel-bridge';

// Convert "A1" to indices
const { row, col } = coordinateToIndex('A1'); // { row: 0, col: 0 }

// Convert indices to "A1"
const coordinate = indexToCoordinate(0, 0); // "A1"

API Reference

Classes

• ExcelReader - Advanced Excel file parsing with full feature support
• ExcelWriter - Advanced Excel file creation with StyleManager
• StyleManager - Dynamic style management for optimal performance

Core Functions

• ExcelBridge.read(buffer) - Parse Excel from buffer
• ExcelBridge.readFromFile(file) - Parse Excel from File object
• ExcelBridge.write(data) - Create Excel Blob from data
• ExcelBridge.writeBuffer(data) - Create Excel Buffer from data
• coordinateToIndex(coord) - Convert Excel coordinate to indices
• indexToCoordinate(row, col) - Convert indices to Excel coordinate

Utility Functions

• dateToExcelSerial(date) - Convert JavaScript Date to Excel serial number
• calculateColumnWidths(data) - Calculate optimal column widths
• escapeXml(text) - Escape XML special characters

Types

interface ExcelData {
  data: any[][];
  styles?: Record<string, CellStyle>;
  validations?: CellValidation[];
  mergeCells?: string[];
  options?: SheetOptions;
}

interface SheetOptions {
  name?: string;
  freezePane?: { row: number; col: number };
  autoWidth?: boolean;
}

interface CellStyle {
  background?: string;
  border?: boolean;
  bold?: boolean;
  color?: string;
  italic?: boolean;
  fontSize?: number;
  fontName?: string;
}

interface CellValidation {
  range: string;
  options: string;
}

interface ExcelWriterOptions {
  creator?: string;
  title?: string;
}

interface ParsedCell {
  value: any;
  type: 'string' | 'number' | 'boolean' | 'empty';
  coordinate: string;
  rowIndex: number;
  columnIndex: number;
}

Development

Building

npm run build         # Build for production
npm run dev           # Watch mode for development
npm run test          # Run tests with Vitest

Code Quality

npm run lint          # Check code quality with ESLint
npm run lint:fix      # Auto-fix linting issues
npm run format        # Format code with Prettier
npm run format:check  # Check formatting without changes

Project Structure

excel-bridge/
├── src/
│   ├── core/
│   │   ├── constants.ts       # XML namespaces & Office Open XML constants
│   │   ├── xml-templates.ts   # XML generators for sheets, styles, workbooks
│   │   ├── style-manager.ts   # Dynamic style management system
│   │   ├── date-utils.ts      # Excel serial date conversion utilities
│   │   ├── column-width.ts    # Auto-width calculation algorithms
│   │   └── zip-manager.ts     # ZIP compression/decompression with fflate
│   ├── reader/
│   │   └── index.ts           # Excel parsing and reading functionality
│   ├── writer/
│   │   └── index.ts           # Advanced Excel creation with StyleManager
│   └── index.ts               # Main entry point and unified API
├── tests/
│   ├── basic.test.ts          # Core functionality tests
│   ├── read-write.test.ts     # Read/Write integration tests
│   ├── zip-structure.test.ts  # ZIP structure validation
│   ├── numbers-only.test.ts    # Numeric data handling
│   └── special-characters.test.ts # Special character handling
├── FEATURES.md                # Detailed feature documentation
├── package.json
├── tsconfig.json
├── eslint.config.js           # ESLint configuration (flat config)
└── .prettierrc                # Prettier configuration

Architecture

This library follows a micro-package architecture for optimal tree-shaking and modularity with advanced Excel features:

Core Module (src/core/)

• constants.ts - Office Open XML namespaces and content types
• xml-templates.ts - XML generators for sheets, styles, workbooks, relationships
• style-manager.ts - Dynamic style management with deduplication and optimization
• date-utils.ts - Excel serial date conversion and validation
• column-width.ts - Intelligent column width calculation algorithms
• zip-manager.ts - ZIP operations using fflate (compression/decompression)

Reader Module (src/reader/)

• ExcelReader class - Parses Excel files from buffers or File objects
• XML to JSON conversion - Extracts cell data, validations, styles, and metadata
• Type-safe parsing - Returns strongly-typed workbook structures
• Multi-sheet support - Handles complex workbook structures

Writer Module (src/writer/)

• ExcelWriter class - Creates Excel files with advanced features
• StyleManager integration - Optimized style generation and management
• Multi-sheet creation - Support for multiple named sheets with options
• Formula support - Native Excel formula handling with placeholders
• Date handling - Automatic JavaScript Date to Excel serial conversion
• Layout features - Merge cells, freeze panes, auto-width columns
• Validation - Data validation and sanitization

Main Entry (src/index.ts)

• Unified ExcelBridge API - Simple interface for common operations
• Advanced exports - All classes, utilities, and types for power users
• Coordinate utilities - Convert between "A1" format and array indices
• Re-exports - Complete API surface for tree-shaking

Technical Details

Dependencies

Production:

• fflate (^0.8.2) - Fast ZIP compression/decompression
• fast-xml-parser (^5.5.1) - High-performance XML parsing

Development:

• TypeScript (^5.9.3) - Type safety and development
• tsup (^8.5.1) - Ultra-fast bundler for ESM/CJS output
• Vitest (^4.0.18) - Modern testing framework
• ESLint (^10.0.3) - Code quality and linting
• Prettier (^3.8.1) - Code formatting

Browser Compatibility

• Modern browsers with ES2022 support
• File API support for reading files
• Blob API support for creating downloads

Node.js Compatibility

• Node.js ^20.19.0, ^22.13.0, or >=24
• Built with SSL support (standard in official distributions)

📋 Known Limitations

• Standard Warnings - Excel may show warnings when opening programmatically generated files (harmless)
• No Shared Strings - Uses inline strings for simplicity and reliability
• Excel 2016+ - Requires modern Excel versions for full compatibility

🚀 Performance

• Lightweight - ~35KB minified bundle size
• Fast Processing - Optimized for large datasets
• Memory Efficient - Stream-based processing for big files
• Tree Shakable - Import only what you need

License

MIT

Author

Built with ❤️ for developers who need powerful Excel manipulation without heavy dependencies.

Excel Bridge - Advanced Excel features, zero dependencies, maximum performance.