title: PDF.js in pyqt5: Error js: Uncaught SyntaxError: Unexpected token '='
body: <p>I used the pyqt5 code with QtWebEngine from <a href="https://stackoverflow.com/a/48053017/17089139">https://stackoverflow.com/a/48053017/17089139</a> to show a PDF file within my desktop application. It worked fine for several months now. After an update of pdf.js to 2.11.338-1 (from archlinux-repo) I get the following error in my pycharm-console:</p>
  <pre><code>js: Uncaught SyntaxError: Unexpected token '='
  </code></pre>
  <p>The application starts, but <strong>no PDF is shown</strong>.
  Where/How to debug this error?</p>
  <ul>
  <li>Python: 3.9</li>
  <li>PyQt5: 5.15.2</li>
  <li>PyQtWebEngine: 5.15.2</li>
  </ul>
  <p><strong>Edit</strong>: Problem seems to be result of unstable (2.11.338) PDF.js - Usage of stable (2.10.377) removes the error and PDF is shown.
  Thanks to @eyllanesc for the hint.</p>