office

Generate Office documents (DOCX, XLSX, PDF, PPTX) with TypeScript. Pure JS libraries that work everywhere: Claude Code CLI, Cloudflare Workers, browsers. Uses docx (Word), xlsx/SheetJS (Excel), pdf-lib (PDF), pptxgenjs (PowerPoint). Use when: creating invoices, reports, spreadsheets, presentations, form filling, exporting data to Office formats, or troubleshooting "Packer.toBuffer", "XLSX.utils", "PDFDocument", "pptxgenjs" errors.

Install with Tessl CLI

npx tessl i github:jezweb/claude-skills --skill office

What are skills?

Review — 86%

Does it follow best practices?

If you maintain this skill, you can automatically optimize it using the tessl CLI to improve its score:

npx tessl skill review --optimize ./path/to/skill

Learn more

Validation — 12 / 16 Passed

Validation for skill structure

SKILL.md

Review

Evals

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: 'B2*C2' }],  // Formula
  ['Widget B', 15, 3, { f: 'B3*C3' }],
  ['', '', '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)

Repository: jezweb/claude-skills
Commit: fa91c34
Last updated: about 1 month ago
Created: about 1 month ago

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.