ExcelTS


Modern TypeScript Excel Workbook Manager - Read, manipulate and write spreadsheet data and styles to XLSX and JSON.

About This Project

ExcelTS is a modern TypeScript Excel workbook manager with:

- 🚀 Zero Runtime Dependencies - Pure TypeScript implementation with no external packages
- ✅ Full TypeScript Support - Complete type definitions and modern TypeScript patterns
- ✅ Modern Build System - Using Rolldown for faster builds
- ✅ Enhanced Testing - Migrated to Vitest with browser testing support
- ✅ ESM First - Native ES Module support with CommonJS compatibility
- ✅ Node 20+ - Optimized for modern Node.js versions
- ✅ Named Exports - All exports are named for better tree-shaking
- ✅ Broad Browser Support - Works in Chrome 89+, Firefox 102+, Safari 14.1+ (with built-in fallbacks for missing CompressionStream)

Translations

- 中文文档

Installation

``bash
npm install @cj-tech-master/excelts
`

Quick Start

$3

`javascript
import { Workbook } from "@cj-tech-master/excelts";

const workbook = new Workbook();
const sheet = workbook.addWorksheet("My Sheet");

// Add data
sheet.addRow(["Name", "Age", "Email"]);
sheet.addRow(["John Doe", 30, "john@example.com"]);
sheet.addRow(["Jane Smith", 25, "jane@example.com"]);

// Save to file
// Node.js only: write to a file path
await workbook.xlsx.writeFile("output.xlsx");

// Browser: use writeBuffer() and save as a Blob (see the Browser Support section)
`

$3

`javascript
import { Workbook } from "@cj-tech-master/excelts";

const workbook = new Workbook();
// Node.js only: read from a file path
await workbook.xlsx.readFile("input.xlsx");

// Browser: use xlsx.load(arrayBuffer) (see the Browser Support section)

const worksheet = workbook.getWorksheet(1);
worksheet.eachRow((row, rowNumber) => {
console.log("Row " + rowNumber + " = " + JSON.stringify(row.values));
});
`

$3

`javascript
// Set cell value and style
const cell = worksheet.getCell("A1");
cell.value = "Hello";
cell.font = {
name: "Arial",
size: 16,
bold: true,
color: { argb: "FFFF0000" }
};
cell.fill = {
type: "pattern",
pattern: "solid",
fgColor: { argb: "FFFFFF00" }
};
`

Features

- Excel Operations
- Create, read, and modify XLSX files
- Multiple worksheet support
- Cell styling (fonts, colors, borders, fills)
- Cell merging and formatting
- Row and column properties
- Freeze panes and split views

- Data Handling
- Rich text support
- Formulas and calculated values
- Data validation
- Conditional formatting
- Images and charts
- Hyperlinks
- Pivot tables

- Advanced Features
- Streaming for large files
- CSV import/export
- Tables with auto-filters
- Page setup and printing options
- Data protection
- Comments and notes

Streaming API

For processing large Excel files without loading them entirely into memory, ExcelTS provides streaming reader and writer APIs.

- Node.js: WorkbookReader supports reading from a file path, and WorkbookWriter supports writing to a filename.
- Browsers: use Uint8Array / ArrayBuffer / Web ReadableStream for reading, and Web WritableStream for writing.
- Note: ExcelTS does not re-export the internal stream utility surface (e.g. Readable, Writable). Prefer standard Web Streams (browser/Node 20+) or Node.js streams.

$3

Read large XLSX files with minimal memory usage:

`javascript
import { WorkbookReader } from "@cj-tech-master/excelts";

// Node.js: read from file path
const reader = new WorkbookReader("large-file.xlsx", {
worksheets: "emit", // emit worksheet events
sharedStrings: "cache", // cache shared strings for cell values
hyperlinks: "ignore", // ignore hyperlinks
styles: "ignore" // ignore styles for faster parsing
});

for await (const worksheet of reader) {
console.log(Reading: ${worksheet.name});
for await (const row of worksheet) {
console.log(row.values);
}
}
`

$3

Write large XLSX files row by row:

`javascript
import { WorkbookWriter } from "@cj-tech-master/excelts";

// Node.js: write to filename
const workbook = new WorkbookWriter({
filename: "output.xlsx",
useSharedStrings: true,
useStyles: true
});

const sheet = workbook.addWorksheet("Data");

// Write rows one at a time
for (let i = 0; i < 1000000; i++) {
sheet.addRow([Row ${i}, i, new Date()]).commit();
}

// Commit worksheet and finalize
sheet.commit();
await workbook.commit();
`

$3

WorkbookWriter can write to a Web WritableStream, and WorkbookReader can read from a Web ReadableStream.

This does not require importing any extra stream utility surface from ExcelTS; it uses the standard Web Streams API.

- Full runnable example: src/modules/excel/examples/web-streams-reader-writer.ts

Run locally (Node.js 20+):

`bash
npx tsx src/modules/excel/examples/web-streams-reader-writer.ts
`

Minimal end-to-end snippet:

`javascript
import { WorkbookWriter, WorkbookReader } from "@cj-tech-master/excelts";

// 1) Write workbook -> Web WritableStream
const chunks = [];
const writable = new WritableStream({
write(chunk) {
chunks.push(chunk);
}
});

const writer = new WorkbookWriter({ stream: writable });
const sheet = writer.addWorksheet("Sheet1");
sheet.addRow(["Name", "Score"]).commit();
sheet.addRow(["Alice", 98]).commit();
await sheet.commit();
await writer.commit();

// 2) Read workbook <- Web ReadableStream
const bytes = new Uint8Array(chunks.reduce((n, c) => n + c.length, 0));
let offset = 0;
for (const c of chunks) {
bytes.set(c, offset);
offset += c.length;
}

const readable = new ReadableStream({
start(controller) {
controller.enqueue(bytes);
controller.close();
}
});

const reader = new WorkbookReader(readable, { worksheets: "emit" });
for await (const ws of reader) {
for await (const row of ws) {
console.log(row.values);
}
}
`

CSV Support

$3

`javascript
import { Workbook } from "@cj-tech-master/excelts";

const workbook = new Workbook();

// Read CSV from file (streaming)
await workbook.csv.readFile("data.csv");

// Read CSV from stream
import fs from "fs";
const stream = fs.createReadStream("data.csv");
await workbook.csv.read(stream, { sheetName: "Imported" });

// Write CSV to file (streaming)
await workbook.csv.writeFile("output.csv");

// Write CSV to stream
const writeStream = fs.createWriteStream("output.csv");
await workbook.csv.write(writeStream);

// Write CSV to buffer
const buffer = await workbook.csv.writeBuffer();
`

$3

`javascript
import { Workbook } from "@cj-tech-master/excelts";

const workbook = new Workbook();

// Load CSV from string
workbook.csv.load(csvString);

// Load CSV from ArrayBuffer (e.g., from fetch or file input)
const response = await fetch("data.csv");
const arrayBuffer = await response.arrayBuffer();
workbook.csv.load(arrayBuffer);

// Write CSV to string
const csvOutput = workbook.csv.writeString();

// Write CSV to Uint8Array buffer
const buffer = workbook.csv.writeBuffer();
`

Browser Support

ExcelTS has native browser support with zero configuration required for modern bundlers.

$3

Simply import ExcelTS - no polyfills or configuration needed:

`javascript
import { Workbook } from "@cj-tech-master/excelts";

const workbook = new Workbook();
const sheet = workbook.addWorksheet("Sheet1");
sheet.getCell("A1").value = "Hello, Browser!";

// Write to buffer and download
const buffer = await workbook.xlsx.writeBuffer();
const blob = new Blob([buffer], {
type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
});
const url = URL.createObjectURL(blob);
// ... trigger download
`

$3

`html


`

$3

For a quick manual smoke test in a real browser (create/download/read XLSX, worksheet protection, etc.), use:

- src/modules/excel/examples/browser-smoke.html

Steps:

`bash
npm run build:browser:bundle
npx serve .
`

Then open http://localhost:3000/src/modules/excel/examples/browser-smoke.html.

$3

- CSV operations are supported using native RFC 4180 implementation
- Use csv.load(stringOrArrayBuffer) to read CSV
- Use csv.writeString() or csv.writeBuffer() to write CSV
- Use xlsx.load(arrayBuffer) instead of xlsx.readFile()
- Use xlsx.writeBuffer() instead of xlsx.writeFile()
- Worksheet protection with passwords is fully supported (pure JS SHA-512)

Requirements

$3

- Node.js >= 20.0.0 (ES2020 native support)

$3

- Chrome >= 89 (March 2021)
- Edge >= 89 (March 2021)
- Firefox >= 102 (June 2022)
- Safari >= 14.1 (April 2021)
- Opera >= 75 (March 2021)

For older browsers without native CompressionStream API (Firefox < 113, Safari < 16.4), ExcelTS automatically uses a built-in pure JavaScript DEFLATE implementation - no configuration or polyfills needed.

ExcelTS does not require crypto.randomUUID() in browsers; it uses an internal UUID v4 generator with a crypto.getRandomValues() fallback.

Maintainer

This project is actively maintained by CJ (@cjnoname).

$3

Active Maintenance - This project is actively maintained with a focus on:

- 🔒 Security Updates - Timely security patches and dependency updates
- 🐛 Bug Fixes - Critical bug fixes and stability improvements
- 📦 Dependency Management - Keeping dependencies up-to-date and secure
- 🔍 Code Review - Reviewing and merging community contributions

$3

While I may not have the bandwidth to develop new features regularly, community contributions are highly valued and encouraged!

- 💡 Pull Requests Welcome - I will review and merge quality PRs promptly
- 🚀 Feature Proposals - Open an issue to discuss new features before implementing
- 🐛 Bug Reports - Please report bugs with reproducible examples
- 📖 Documentation - Improvements to documentation are always appreciated

API Documentation

For detailed API documentation, please refer to the comprehensive documentation sections:

- Workbook Management
- Worksheets
- Cells and Values
- Styling
- Formulas
- Data Validation
- Conditional Formatting
- File I/O

Contributing Guidelines

Contributions are welcome! Please feel free to submit a Pull Request.

$3

1. Bug Fixes: Add a unit-test or integration-test (in src/**/__tests__) that reproduces the issue
2. New Features: Open an issue first to discuss the feature and implementation approach
3. Documentation: Update relevant documentation and type definitions
4. Code Style: Follow the existing code style and pass all linters (npm run lint)
5. Tests: Ensure all tests pass (npm test`) and add tests for new functionality

$3

- Version Numbers: Please do not modify package version in PRs. Versions are managed through releases.
- License: All contributions will be included under the project's MIT license
- Commit Messages: Write clear, descriptive commit messages

$3

If you need help or have questions:

- 📖 Check existing issues and documentation
- 💬 Open a new issue for discussion
- 🐛 Use issue templates for bug reports

License

MIT License

See LICENSE.

Third-party software notices and attributions are provided in THIRD_PARTY_NOTICES.md.

Links

- GitHub Repository
- Issue Tracker

Changelog

See CHANGELOG.md for detailed version history.