Office Document Generation

Status: Production Ready Last Updated: 2026-01-12 Dependencies: None (pure JavaScript libraries) Latest Versions: docx@9.5.0, xlsx@0.18.5, pdf-lib@1.17.1, pptxgenjs@4.0.1

Overview

Generate Microsoft Office documents and PDFs programmatically with TypeScript. All libraries are pure JavaScript with zero native dependencies, enabling universal runtime support:

Format Library Workers Browser Node.js

DOCX docx

✅ ✅ ✅

XLSX xlsx (SheetJS) ✅ ✅ ✅

PDF pdf-lib

✅ ✅ ✅

PPTX pptxgenjs

⚠️* ✅ ✅

*PPTX in Workers: Works for local images/data. Remote image fetching needs workaround (uses https module).

Quick Start

Installation

Install all four (or pick what you need)

npm install docx xlsx pdf-lib pptxgenjs

Create a Word Document (30 seconds)

import { Document, Packer, Paragraph, TextRun } from 'docx'; import { writeFileSync } from 'fs';

const doc = new Document({ sections: [{ children: [ new Paragraph({ children: [ new TextRun({ text: 'Hello World', bold: true, size: 48 }), ], }), ], }], });

// Node.js: Save to file const buffer = await Packer.toBuffer(doc); writeFileSync('hello.docx', buffer);

// Browser/Workers: Get as blob const blob = await Packer.toBlob(doc);

Create an Excel Spreadsheet (30 seconds)

import * as XLSX from 'xlsx';

// Create workbook with data const data = [ ['Name', 'Amount', 'Date'], ['Invoice #1', 1500, '2026-01-12'], ['Invoice #2', 2300, '2026-01-13'], ];

const worksheet = XLSX.utils.aoa_to_sheet(data); const workbook = XLSX.utils.book_new(); XLSX.utils.book_append_sheet(workbook, worksheet, 'Invoices');

// Node.js: Save to file XLSX.writeFile(workbook, 'invoices.xlsx');

// Browser/Workers: Get as buffer const buffer = XLSX.write(workbook, { type: 'buffer', bookType: 'xlsx' });

Create a PDF (30 seconds)

import { PDFDocument, StandardFonts, rgb } from 'pdf-lib';

const pdfDoc = await PDFDocument.create(); const page = pdfDoc.addPage([612, 792]); // Letter size const font = await pdfDoc.embedFont(StandardFonts.Helvetica);

page.drawText('Hello World', { x: 50, y: 700, size: 24, font, color: rgb(0, 0, 0), });

// Get as bytes (works everywhere) const pdfBytes = await pdfDoc.save();

// Node.js: Save to file writeFileSync('hello.pdf', pdfBytes);

Create a PowerPoint (30 seconds)

import pptxgen from 'pptxgenjs';

const pptx = new pptxgen(); pptx.author = 'Your Name'; pptx.title = 'Sample Presentation';

// Add a slide const slide = pptx.addSlide(); slide.addText('Hello World', { x: 1, y: 1, w: 8, h: 1.5, fontSize: 36, bold: true, color: '363636', });

// Node.js: Save to file await pptx.writeFile({ fileName: 'hello.pptx' });

// Browser: Trigger download await pptx.writeFile({ fileName: 'hello.pptx' });

DOCX: Word Documents

Key Concepts

The docx package uses a builder pattern:

• Document - The root container

• Section - Contains pages (most docs have 1 section)

• Paragraph - A line/block of text

• TextRun - Formatted text within a paragraph

• Table - Grid of TableRow → TableCell → Paragraph

Document with Headings and Paragraphs

import { Document, Packer, Paragraph, TextRun, HeadingLevel } from 'docx';

const doc = new Document({ sections: [{ children: [ new Paragraph({ text: 'Monthly Report', heading: HeadingLevel.HEADING_1, }), new Paragraph({ children: [ new TextRun('This is a '), new TextRun({ text: 'bold', bold: true }), new TextRun(' and '), new TextRun({ text: 'italic', italics: true }), new TextRun(' text example.'), ], }), ], }], });

Tables

import { Document, Table, TableRow, TableCell, Paragraph, WidthType } from 'docx';

const table = new Table({ width: { size: 100, type: WidthType.PERCENTAGE }, rows: [ new TableRow({ children: [ new TableCell({ children: [new Paragraph('Header 1')] }), new TableCell({ children: [new Paragraph('Header 2')] }), ], }), new TableRow({ children: [ new TableCell({ children: [new Paragraph('Data 1')] }), new TableCell({ children: [new Paragraph('Data 2')] }), ], }), ], });

const doc = new Document({ sections: [{ children: [table] }], });

Images

import { Document, Paragraph, ImageRun } from 'docx'; import { readFileSync } from 'fs';

const imageBuffer = readFileSync('logo.png');

const doc = new Document({ sections: [{ children: [ new Paragraph({ children: [ new ImageRun({ data: imageBuffer, transformation: { width: 200, height: 100 }, type: 'png', }), ], }), ], }], });

Export Patterns

// Node.js - Save to file import { writeFileSync } from 'fs'; const buffer = await Packer.toBuffer(doc); writeFileSync('document.docx', buffer);

// Browser - Download const blob = await Packer.toBlob(doc); const url = URL.createObjectURL(blob); const a = document.createElement('a'); a.href = url; a.download = 'document.docx'; a.click();

// Cloudflare Workers - Return as Response const buffer = await Packer.toBuffer(doc); return new Response(buffer, { headers: { 'Content-Type': 'application/vnd.openxmlformats-officedocument.wordprocessingml.document', 'Content-Disposition': 'attachment; filename="document.docx"', }, });

XLSX: Excel Spreadsheets

Key Concepts

SheetJS (xlsx) uses utility functions:

• Workbook - Container for sheets

• Worksheet - Single sheet (grid of cells)

• utils.aoa_to_sheet - Array of arrays → worksheet

• utils.json_to_sheet - JSON array → worksheet

• utils.book_new/book_append_sheet - Create/add sheets

From Array of Arrays

import * as XLSX from 'xlsx';

const data = [ ['Product', 'Price', 'Quantity', 'Total'], ['Widget A', 10, 5, { f: 'B2C2' }], // Formula ['Widget B', 15, 3, { f: 'B3C3' }], ['', '', 'Grand Total:', { f: 'SUM(D2:D3)' }], ];

const ws = XLSX.utils.aoa_to_sheet(data); const wb = XLSX.utils.book_new(); XLSX.utils.book_append_sheet(wb, ws, 'Sales');

From JSON

const invoices = [ { id: 1, customer: 'Acme Corp', amount: 1500, date: '2026-01-12' }, { id: 2, customer: 'Globex', amount: 2300, date: '2026-01-13' }, ];

const ws = XLSX.utils.json_to_sheet(invoices); const wb = XLSX.utils.book_new(); XLSX.utils.book_append_sheet(wb, ws, 'Invoices');

Column Widths

// Set column widths (in characters) ws['!cols'] = [ { wch: 10 }, // Column A { wch: 20 }, // Column B { wch: 15 }, // Column C ];

Multiple Sheets

const wb = XLSX.utils.book_new();

const summaryData = [['Total Sales', 3800]]; const detailData = [['Item', 'Amount'], ['Item 1', 1500], ['Item 2', 2300]];

XLSX.utils.book_append_sheet(wb, XLSX.utils.aoa_to_sheet(summaryData), 'Summary'); XLSX.utils.book_append_sheet(wb, XLSX.utils.aoa_to_sheet(detailData), 'Details');

Export Patterns

// Node.js - Save to file XLSX.writeFile(workbook, 'report.xlsx');

// Browser/Workers - Get buffer const buffer = XLSX.write(workbook, { type: 'buffer', bookType: 'xlsx' });

// Cloudflare Workers - Return as Response return new Response(buffer, { headers: { 'Content-Type': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', 'Content-Disposition': 'attachment; filename="report.xlsx"', }, });

PDF: PDF Documents

Key Concepts

pdf-lib uses a page-based approach:

• PDFDocument - The PDF file

• PDFPage - Individual page

• Coordinates - Origin at BOTTOM-LEFT (not top-left!)

• Units - Points (72 points = 1 inch)

Standard Page Sizes

// Common sizes in points [width, height] const LETTER = [612, 792]; // 8.5" x 11" const A4 = [595.28, 841.89]; // 210mm x 297mm const LEGAL = [612, 1008]; // 8.5" x 14"

Text and Fonts

import { PDFDocument, StandardFonts, rgb } from 'pdf-lib';

const pdfDoc = await PDFDocument.create(); const page = pdfDoc.addPage([612, 792]);

// Embed standard fonts const helvetica = await pdfDoc.embedFont(StandardFonts.Helvetica); const helveticaBold = await pdfDoc.embedFont(StandardFonts.HelveticaBold);

// Draw text (y=0 is BOTTOM of page) page.drawText('Invoice #12345', { x: 50, y: 750, // Near top of page size: 24, font: helveticaBold, color: rgb(0, 0, 0), });

page.drawText('Thank you for your business!', { x: 50, y: 50, // Near bottom of page size: 12, font: helvetica, color: rgb(0.5, 0.5, 0.5), });

Drawing Shapes

// Rectangle page.drawRectangle({ x: 50, y: 600, width: 200, height: 100, borderColor: rgb(0, 0, 0), borderWidth: 1, color: rgb(0.95, 0.95, 0.95), // Fill color });

// Line page.drawLine({ start: { x: 50, y: 500 }, end: { x: 550, y: 500 }, thickness: 1, color: rgb(0, 0, 0), });

Images

// From URL/fetch const imageBytes = await fetch('https://example.com/logo.png').then(r => r.arrayBuffer()); const image = await pdfDoc.embedPng(imageBytes);

// Or embedJpg for JPEG // const image = await pdfDoc.embedJpg(imageBytes);

page.drawImage(image, { x: 50, y: 700, width: 100, height: 50, });

Fill PDF Forms

import { PDFDocument } from 'pdf-lib';

// Load existing PDF with form const existingPdfBytes = await fetch('form.pdf').then(r => r.arrayBuffer()); const pdfDoc = await PDFDocument.load(existingPdfBytes);

// Get form and fields const form = pdfDoc.getForm(); const nameField = form.getTextField('customer_name'); const dateField = form.getTextField('date');

// Fill fields nameField.setText('John Doe'); dateField.setText('2026-01-12');

// Flatten form (make fields non-editable) form.flatten();

const pdfBytes = await pdfDoc.save();

Merge PDFs

import { PDFDocument } from 'pdf-lib';

const pdf1Bytes = await fetch('doc1.pdf').then(r => r.arrayBuffer()); const pdf2Bytes = await fetch('doc2.pdf').then(r => r.arrayBuffer());

const mergedPdf = await PDFDocument.create(); const pdf1 = await PDFDocument.load(pdf1Bytes); const pdf2 = await PDFDocument.load(pdf2Bytes);

// Copy all pages from both documents const pages1 = await mergedPdf.copyPages(pdf1, pdf1.getPageIndices()); const pages2 = await mergedPdf.copyPages(pdf2, pdf2.getPageIndices());

pages1.forEach(page => mergedPdf.addPage(page)); pages2.forEach(page => mergedPdf.addPage(page));

const mergedBytes = await mergedPdf.save();

PPTX: PowerPoint Presentations

Key Concepts

pptxgenjs uses a slide-based approach:

• Presentation - The PPTX file (new pptxgen())

• Slide - Individual slide (addSlide())

• Elements - Text, images, shapes, tables, charts

• Units - Inches by default (can change to cm/points)

Basic Presentation

import pptxgen from 'pptxgenjs';

const pptx = new pptxgen(); pptx.author = 'Author Name'; pptx.title = 'Presentation Title'; pptx.subject = 'Subject'; pptx.company = 'Company';

// Title slide const titleSlide = pptx.addSlide(); titleSlide.addText('Quarterly Report', { x: 0.5, y: 2, w: 9, h: 1, fontSize: 44, bold: true, color: '0066CC', align: 'center', }); titleSlide.addText('Q1 2026', { x: 0.5, y: 3.5, w: 9, h: 0.5, fontSize: 24, color: '666666', align: 'center', });

Slide with Bullet Points

const contentSlide = pptx.addSlide();

// Title contentSlide.addText('Key Highlights', { x: 0.5, y: 0.5, w: 9, h: 0.8, fontSize: 32, bold: true, color: '333333', });

// Bullet points contentSlide.addText([ { text: 'Revenue up 25% YoY', options: { bullet: true, fontSize: 20 } }, { text: 'Customer base grew to 10,000', options: { bullet: true, fontSize: 20 } }, { text: 'New product launch successful', options: { bullet: true, fontSize: 20 } }, { text: 'Expanded to 5 new markets', options: { bullet: true, fontSize: 20 } }, ], { x: 0.5, y: 1.5, w: 8, h: 4, valign: 'top' });

Tables

const tableSlide = pptx.addSlide();

tableSlide.addText('Sales Summary', { x: 0.5, y: 0.5, w: 9, h: 0.8, fontSize: 28, bold: true, });

const tableData = [ [{ text: 'Region', options: { bold: true, fill: '0066CC', color: 'FFFFFF' } }, { text: 'Q1', options: { bold: true, fill: '0066CC', color: 'FFFFFF' } }, { text: 'Q2', options: { bold: true, fill: '0066CC', color: 'FFFFFF' } }], ['North America', '$2.5M', '$2.8M'], ['Europe', '$1.8M', '$2.1M'], ['Asia Pacific', '$1.2M', '$1.5M'], ];

tableSlide.addTable(tableData, { x: 0.5, y: 1.5, w: 9, border: { pt: 1, color: 'CCCCCC' }, fontFace: 'Arial', fontSize: 14, align: 'center', valign: 'middle', });

Charts

const chartSlide = pptx.addSlide();

chartSlide.addText('Revenue Trend', { x: 0.5, y: 0.5, w: 9, h: 0.6, fontSize: 28, bold: true, });

chartSlide.addChart(pptx.ChartType.line, [ { name: 'Revenue', labels: ['Jan', 'Feb', 'Mar', 'Apr'], values: [100, 120, 150, 180] }, { name: 'Expenses', labels: ['Jan', 'Feb', 'Mar', 'Apr'], values: [80, 85, 90, 95] }, ], { x: 0.5, y: 1.2, w: 9, h: 4, showLegend: true, legendPos: 'b', showTitle: false, });

Images

import { readFileSync } from 'fs';

const imageSlide = pptx.addSlide();

// From file (Node.js) imageSlide.addImage({ path: 'logo.png', x: 0.5, y: 0.5, w: 2, h: 1, });

// From base64 const imageBase64 = readFileSync('chart.png').toString('base64'); imageSlide.addImage({ data: image/png;base64,${imageBase64}, x: 0.5, y: 2, w: 4, h: 3, });

// From URL (Node.js only - uses https module) imageSlide.addImage({ path: 'https://example.com/image.png', x: 5, y: 2, w: 4, h: 3, });

Shapes

const shapeSlide = pptx.addSlide();

// Rectangle shapeSlide.addShape(pptx.ShapeType.rect, { x: 0.5, y: 0.5, w: 3, h: 2, fill: { color: '0066CC' }, line: { color: '004499', pt: 2 }, });

// Circle/Oval shapeSlide.addShape(pptx.ShapeType.ellipse, { x: 4, y: 0.5, w: 2, h: 2, fill: { color: '00AA00' }, });

// Arrow shapeSlide.addShape(pptx.ShapeType.rightArrow, { x: 1, y: 3, w: 3, h: 1, fill: { color: 'FF6600' }, });

Slide Layouts and Masters

// Define a master slide pptx.defineSlideMaster({ title: 'COMPANY_MASTER', background: { color: 'FFFFFF' }, objects: [ { text: { text: 'Company Name', options: { x: 0.5, y: 0.2, w: 4, h: 0.3, fontSize: 10, color: '999999' } } }, { line: { x: 0.5, y: 0.6, w: 9, h: 0, line: { color: '0066CC', pt: 2 } } }, ], });

// Use the master const slide = pptx.addSlide({ masterName: 'COMPANY_MASTER' });

Export Patterns

// Node.js - Save to file await pptx.writeFile({ fileName: 'presentation.pptx' });

// Browser - Trigger download await pptx.writeFile({ fileName: 'presentation.pptx' });

// Get as base64 (for email, API, etc.) const base64 = await pptx.write({ outputType: 'base64' });

// Get as Blob (browser) const blob = await pptx.write({ outputType: 'blob' });

// Get as ArrayBuffer const arrayBuffer = await pptx.write({ outputType: 'arraybuffer' });

// Cloudflare Workers - Return as Response const arrayBuffer = await pptx.write({ outputType: 'arraybuffer' }); return new Response(arrayBuffer, { headers: { 'Content-Type': 'application/vnd.openxmlformats-officedocument.presentationml.presentation', 'Content-Disposition': 'attachment; filename="presentation.pptx"', }, });

Cloudflare Workers Integration

All four libraries work in Cloudflare Workers (PPTX with caveats for remote images).

DOCX Generation Endpoint

import { Hono } from 'hono'; import { Document, Packer, Paragraph, TextRun } from 'docx';

const app = new Hono();

app.get('/api/invoice/:id', async (c) => { const invoiceId = c.req.param('id');

const doc = new Document({ sections: [{ children: [ new Paragraph({ children: [new TextRun({ text: Invoice #${invoiceId}, bold: true, size: 48 })], }), ], }], });

const buffer = await Packer.toBuffer(doc);

return new Response(buffer, { headers: { 'Content-Type': 'application/vnd.openxmlformats-officedocument.wordprocessingml.document', 'Content-Disposition': attachment; filename="invoice-${invoiceId}.docx", }, }); });

export default app;

HTML to PDF with Browser Rendering

For complex layouts with CSS, use Cloudflare Browser Rendering (paid feature):

import puppeteer from '@cloudflare/puppeteer';

export default { async fetch(request, env) { const browser = await puppeteer.launch(env.BROWSER); const page = await browser.newPage();

// Set HTML content
await page.setContent(`
  <html>
    <head>
      <style>
        body { font-family: Arial, sans-serif; padding: 40px; }
        h1 { color: #333; }
        table { width: 100%; border-collapse: collapse; }
        td, th { border: 1px solid #ddd; padding: 8px; }
      </style>
    </head>
    <body>
      <h1>Invoice #12345</h1>
      <table>
        <tr><th>Item</th><th>Amount</th></tr>
        <tr><td>Service</td><td>$500</td></tr>
      </table>
    </body>
  </html>
`);

const pdf = await page.pdf({ format: 'A4' });
await browser.close();

return new Response(pdf, {
  headers: {
    'Content-Type': 'application/pdf',
    'Content-Disposition': 'attachment; filename="invoice.pdf"',
  },
});

}, };

wrangler.jsonc binding:

{ "browser": { "binding": "BROWSER" } }

Critical Rules

Always Do

✅ Use await Packer.toBuffer() for DOCX (it's async) ✅ Remember PDF coordinates start at BOTTOM-LEFT ✅ Use type: 'buffer' for XLSX in Workers/browser ✅ Embed fonts in PDF before using them ✅ Set proper Content-Type headers for downloads ✅ Use await pptx.writeFile() or await pptx.write() for PPTX ✅ Use base64 images in PPTX for Workers (avoid remote URLs)

Never Do

❌ Use Packer.toBuffer() without await (returns Promise) ❌ Assume PDF y=0 is at top (it's at bottom) ❌ Use writeFile in Workers (use Response instead) ❌ Forget to set Content-Disposition for downloads ❌ Use Node.js fs module in browser/Workers ❌ Use PPTX path URLs in Workers (https module not available)

Known Issues Prevention

Issue #1: DOCX Packer Returns Promise

Error: [object Promise] in file or empty document Why: Packer.toBuffer() is async but called without await Prevention: Always await Packer.toBuffer(doc)

Issue #2: PDF Text at Wrong Position

Error: Text appears at bottom of page or off-page Why: PDF coordinates have origin at bottom-left, not top-left Prevention: For text near top, use high y values (e.g., y=750 for letter size)

Issue #3: XLSX Formula Not Calculating

Error: Cell shows formula text instead of result Why: SheetJS doesn't execute formulas, Excel does on open Prevention: This is expected - formulas calculate when opened in Excel

Issue #4: Workers DOCX/PDF Returns Empty

Error: Downloaded file is empty or corrupted Why: Returning wrong type or missing Content-Type header Prevention: Return buffer directly with proper headers

Issue #5: PPTX Remote Images Fail in Workers

Error: https is not defined or image not appearing Why: pptxgenjs uses Node.js https module for remote images Prevention: Use base64 data URIs or local images in Workers environment

Using Bundled Resources

Templates (templates/)

• docx-basic.ts

• Complete Word document with headings, tables, images

• xlsx-basic.ts

• Excel workbook with formulas and formatting

• pdf-basic.ts

• PDF with text, images, shapes

• pptx-basic.ts

• PowerPoint with slides, charts, tables

• workers-pdf.ts

• Cloudflare Workers PDF generation example

References (references/)

• docx-api.md

• Quick reference for docx npm package

• xlsx-api.md

• Quick reference for SheetJS functions

• pdf-lib-api.md

• Quick reference for pdf-lib methods

• pptxgenjs-api.md

• Quick reference for pptxgenjs

Scripts (scripts/)

• verify-deps.sh
• Check library versions are current

Limitations vs Anthropic's Official Skills

This skill focuses on document creation with portable TypeScript libraries:

Feature This Skill Anthropic's Skills

Create DOCX/XLSX/PDF/PPTX ✅ ✅

Works in Cloudflare Workers ✅ ❌

Plugin installable ✅ ❌

TypeScript-first ✅ ❌ (Python)

Edit existing DOCX with tracked changes ❌ ✅

Excel formula validation ❌ ✅

OCR scanned PDFs ❌ ✅

For advanced editing scenarios (tracked changes, formula validation), consider Anthropic's official skills with Python tooling.

Package Versions (Verified 2026-01-12)

{ "dependencies": { "docx": "^9.5.0", "xlsx": "^0.18.5", "pdf-lib": "^1.17.1", "pptxgenjs": "^4.0.1" } }

Official Documentation

• docx: https://docx.js.org/

• SheetJS (xlsx): https://docs.sheetjs.com/

• pdf-lib: https://pdf-lib.js.org/

• pptxgenjs: https://gitbrent.github.io/PptxGenJS/

• Cloudflare Browser Rendering: https://developers.cloudflare.com/browser-rendering/

Complete Setup Checklist

• Installed required packages (npm install docx xlsx pdf-lib )

• Verified import statements match runtime (Node.js vs browser)

• Used proper export method for target environment

• Set Content-Type headers for HTTP responses

• Tested document opens correctly in target application

• Confirmed Workers compatibility (if deploying to edge)