window is not defined in SSR

While using pdfjs in frameworks with SSR like Next.js or Gatsby there is an error while build phase ReferenceError: window is not defined

The error occurs at line 563 in ui_utils.js

Looks like all changes needs is:

const animationStarted = new Promise(function (resolve) {
  if (
    typeof PDFJSDev !== "undefined" &&
-   PDFJSDev.test("LIB && TESTING") &&
+   PDFJSDev.test("LIB && TESTING") ||
    typeof window === "undefined"
  ) {
    // Prevent "ReferenceError: window is not defined" errors when running the
    // unit-tests in Node.js/Travis.
    setTimeout(resolve, 20);
    return;
  }
  window.requestAnimationFrame(resolve);
});

There is an issue in react-pdf: https://github.com/wojtekmaj/react-pdf/issues/657

[wojtekmaj]

but which particular files/folders are you using?

I think the issue here was that I needed PdfLinkService to get links working in PDFs, and PDFLinkService required EventBus, which, when imported, evaluated the entire ui_utils.js unfortunately, because ui_utils isn’t side effect free. I created our own custom link service now in React-PDPF 5.3.0 beta so that should no longer be an issue - at least from our side, unless someone else will try the same thing.

[Snuffleupagus]

Another way to fix it would be to simply write

const animationStarted = new Promise(function (resolve) {
  if (typeof window === "undefined" || typeof window.requestAnimationFrame !== "function")) {
    setTimeout(resolve, 20);
  } else {
    window.requestAnimationFrame(resolve);
  }
});

That’s not really an acceptable solution though, since as a general rule we don’t want to add useless runtime checks in Firefox; please note https://github.com/mozilla/pdf.js/issues/13057#issuecomment-792249114.