document-generation-pdf

Document Generation & PDF Automation

Expert in generating, filling, and assembling PDF documents programmatically for legal, HR, and business workflows.

When to Use

✅ Use for:

• Legal form automation (expungement, immigration, contracts)
• Invoice/receipt generation at scale
• Certificate creation (completion, participation, awards)
• Contract assembly from templates
• Government form filling (IRS, court filings)
• Multi-document packet creation

❌ NOT for:

• Simple PDF viewing (use browser or pdf.js)
• Basic file conversion (use online tools)
• OCR text extraction (use Tesseract.js or AWS Textract)
• PDF editing by hand (use Adobe Acrobat)

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Technology Selection

pdf-lib vs Puppeteer vs LaTeX

Feature	pdf-lib	Puppeteer	LaTeX
Form filling	✅ Native	❌ Complex	❌ No
Template rendering	❌ No	✅ HTML/CSS	✅ Templates
Performance (1000 PDFs)	5s	60s	30s
File size	Small	Medium	Small
Signature fields	✅ Yes	❌ No	❌ No
Best for	Government forms	Invoices, reports	Academic papers

Timeline:

• 2000s: LaTeX for academic documents
• 2010: PDFKit (Node.js) for generation
• 2017: Puppeteer for HTML → PDF
• 2019: pdf-lib for pure JS form filling
• 2024: pdf-lib is gold standard for forms

Decision tree:

Need to fill existing form? → pdf-lib
Need complex layouts? → Puppeteer (HTML/CSS)
Need academic formatting? → LaTeX
Need to merge PDFs? → pdf-lib
Need digital signatures? → pdf-lib + DocuSign API

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Common Anti-Patterns

Anti-Pattern 1: Using Puppeteer for Simple Form Filling

Novice thinking: "I'll use Puppeteer for everything, it's versatile"

Problem: 12x slower, 10x more memory, can't preserve form fields.

Wrong approach:

// ❌ Puppeteer for simple form filling (SLOW!)
import puppeteer from 'puppeteer';

async function fillForm(data: FormData): Promise<Buffer> {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();

  // Load PDF in browser
  await page.goto(`file://${pdfPath}`);

  // Somehow fill form fields? (hacky)
  await page.evaluate((data) => {
    // Can't easily access PDF form fields from DOM
    // Would need to convert PDF → HTML first
  }, data);

  const pdf = await page.pdf();
  await browser.close();

  return pdf;
}