document-exports

Document Exports (PDF / CSV) for Node + Express

Class of work: build a backend endpoint that returns a binary PDF or a text CSV for download (Content-Disposition: attachment), then write a test that actually verifies the bytes — not just status === 200.

Load this skill when the task is "export to PDF", "generate a CSV report", "statement/extrato as PDF", or any downloadable-file endpoint that must be tested with supertest/Jest.

When to use

• PDF generation with pdfkit streamed to res.
• CSV generation (Excel-pt-BR friendly, BOM, quoted fields).
• Any test that must assert on PDF content or CSV bytes.

Stack assumptions

Node, Express, pdfkit (PDF), jest + supertest (tests), Mongoose-style userId scoping. Money is stored/aggregated as integer cents (amountCents) — never float. Format to R$ 1.234,56 or decimal 1234.56 only at render time.

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PDF with pdfkit (streamed, do NOT buffer whole file)

Pipe the pdfkit Document straight to the response. pdfkit is a WritableStream.

const PDFDocument = require('pdfkit');

function gerarExtratoPDF({ usuario, month, resumo, lancamentos }) {
  const doc = new PDFDocument({ margin: 50, size: 'A4', compress: false });
  // ... draw header, summary, table ...
  doc.flushPages();
  return doc; // caller does: doc.pipe(res); doc.end();
}

// controller
const doc = pdfService.gerarExtratoPDF({ /*...*/ });
res.setHeader('Content-Type', 'application/pdf');
res.setHeader('Content-Disposition', `attachment; filename="extrato-${month}.pdf"`);
doc.pipe(res);
doc.end();

compress: false keeps text readable in the binary (useful for test inspection / auditing). Set bufferPages: true only if you need to draw a footer on every page.

CSV (Excel pt-BR friendly)

• Emit CRLF line endings (\r\n) and a UTF-8 BOM so Excel opens acentos correctly. Add the BOM once, in bytes, at the controller — do NOT prepend a BOM character inside the string (double-BOM bug).
• Escape fields containing , " \n \r by wrapping in "..." and doubling inner quotes (" → "").