Configuring pdf.js

Most applications configure nothing. configurePdfjs(), called once before the first PdfDocument renders, changes how ParaPDF loads pdf.js:

import { configurePdfjs } from "parapdf";

configurePdfjs({ documentOptions: { withCredentials: true } });

Option
assetBase	Base URL of a copy of node_modules/parapdf/pdfjs/, ending with a slash, for bundlers that do not emit the files themselves (see Bundlers).
imageResourcesPath	Base URL of pdf.js’s annotation icons, which comments without an appearance of their own show, ending with a slash. By default they are the icons the package ships, or ${assetBase}web/images/ with assetBase.
workerSrc	URL of pdf.js’s worker script, when it is not ${assetBase}pdf.worker.js.
build	legacyBuild from parapdf/legacy: pdf.js’s legacy build for older browsers, with its worker and files from the package like the modern build’s.
pdfjs	Loads another build of the same pdf.js version, with its worker as workerSrc and its files as assetBase.
enableHWA	GPU-backed canvases, true by default; false asks pdf.js for CPU-backed ones, which block the main thread for longer in Chromium and drop more frames in WebKit, though WebKit holds less memory with them.
documentOptions	More pdf.js getDocument parameters for every document, such as withCredentials, httpHeaders, or password.
rendererSrc	pdf.js’s renderer worker, which draws pages off the main thread; it is only in unreleased pdf.js builds so far.

Loading early

preloadPdfjs() starts loading pdf.js and its worker before any PdfDocument renders, for example when the pointer moves over a link to a document. The first PdfDocument starts it anyway, with the worker’s download beside pdf.js’s module rather than after it.

The legacy build

For browsers that need pdf.js’s legacy build:

import { configurePdfjs } from "parapdf";
import { legacyBuild } from "parapdf/legacy";

configurePdfjs({ build: legacyBuild });

Only applications that import parapdf/legacy emit the legacy worker, but the modern worker, about 1.3 MB, is emitted either way: the build output grows, the browser fetches only the worker it uses.

The version

pdfjsVersion is the version of pdf.js the package ships, for URLs of files you serve yourself. ParaPDF depends on that version exactly: pdf.js refuses a worker of another version, so an application cannot move to another pdf.js by itself. When pdf.js publishes a security fix, a ParaPDF release moves to it (security policy).