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Loading PDFs

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#Loading PDFs

Use openPdf(...) for scripts and one-off work:

ts 
import { openPdf } from "clawpdf";

await using pdf = await openPdf("report.pdf");
console.log(pdf.pageCount);

Use createEngine(...) for servers:

ts 
import { createEngine } from "clawpdf";

await using engine = await createEngine();
const pdf = await engine.open(pdfBytes);
try {
  console.log(pdf.text());
} finally {
  pdf.destroy();
}

#Inputs

Accepted inputs:

  • Uint8Array and ArrayBuffer: used directly.
  • Node file path string: read from disk.
  • URL string or URL: fetched.
  • Blob: read with arrayBuffer().

In browsers, string inputs must be URLs. Path-like strings throw PdfFormatError.

HTTP and HTTPS reads have a 30-second deadline covering both response headers and the complete response body. Override it with fetchTimeoutMs, use 0 to disable the deadline, or pass an AbortSignal as signal for caller cancellation.

Downloads have no size cap by default (fetchMaxBytes: 0). Opt into an HTTP(S) response-body budget by setting fetchMaxBytes to a positive safe integer. Declared Content-Length values above the budget fail before the body is read; streamed bodies that exceed it also throw PdfBudgetError. Rejected downloads are cancelled. File, blob, and data URL inputs are unaffected by the size budget:

ts 
await using pdf = await openPdf(url, {
  fetchTimeoutMs: 10_000,
  fetchMaxBytes: 10_000_000,
  signal: controller.signal,
});

Failed HTTP reads cancel the outstanding request and its unread response body before reporting the error.

#Lifetime

openPdf(...) creates a private engine for the document. Destroying the document also destroys that private engine.

createEngine(...) returns a long-lived engine you own. engine.destroy() closes still-open documents before destroying PDFium. Calling destroy() twice is safe. Calling other methods after destroy throws PdfDestroyedError.

#Metadata

pdf.metadata.creationDate and pdf.metadata.modificationDate are JavaScript Date values. PDF timezone offsets are applied to preserve the recorded instant. Dates without a timezone are interpreted as UTC. Missing month and day default to January and the first day; missing time fields default to zero. Invalid dates are omitted from the metadata instead of being rolled into another date.

#Passwords

Pass a user password when opening:

ts 
await using pdf = await openPdf("secret.pdf", { password: "secret" });

Wrong or missing passwords throw PdfPasswordError.

#Load Options

createEngine(options) accepts:

  • wasmUrl: URL/path passed to the Emscripten loader.
  • wasmBinary: raw WASM bytes.
  • instantiateWasm: custom Emscripten instantiate hook.
  • maxRenderPixels: per-render pixel hard cap.

Node loads the packaged dist/vendor/pdfium.esm.wasm automatically.