[Bug]: Unworking demo viewer on chrome

[RemiRiu95]

Attach (recommended) or Link to PDF file

https://mozilla.github.io/pdf.js/web/viewer.html

Web browser and its version

Chrome Version 139.0.7258.127 & 143.0.7499.192 | both 64-bit

Operating system and its version

Ubuntu 24.04 TLS

PDF.js version

The one provided by https://mozilla.github.io/pdf.js/web/viewer.html

Is the bug present in the latest PDF.js version?

Yes

Is a browser extension

No

Steps to reproduce the problem

• Go to https://mozilla.github.io/pdf.js/web/viewer.html with Chrome on Linux Ubuntu
• See Javascript error "TypeError: hashOriginal.toHex is not a function"

What is the expected behavior?

Working viewer

What went wrong?

Viewer couldn't load with javascript console error "TypeError: hashOriginal.toHex is not a function"

Link to a viewer

https://mozilla.github.io/pdf.js/web/viewer.html

Additional context

No response

[EugenMayer]

This is not chrome specific. The latest edge release, that supports toHex (https://caniuse.com/mdn-javascript_builtins_uint8array_tohex), is from Sept 2025. Using toHex without a ship could a be a rather aggressive upgrade policy.

We had to downgrade to an older PDFJS release due to this toHex issue. It affected all our regression tests. Our playwright version https://playwright.dev/docs/release-notes#version-154 (7 months old) does not support toHex due to the browser versions included.

Just wanted to make it transparent that toHex seems to be a very new feature and i'am not sure that it would be worth locking out edge older then 5 months from even working with PDFJS.

[bjoernmartin]

We have the same issue with Cypress 15.11.0 which was released 2 weeks ago. It uses Chrome 138 seems to use Electron 37.0
from June 2025 for the E2E tests (as it reports Chrome 138 as browser version) and thus fails with the same error.

I don't know how qutebrowser/qutebrowser#8859 may play into this. It seems to have added a polyfill for the affected function and it mentions "PDF js" but I don't see which dependencies pdf.js pulls in (not a JS expert). But if qutebrowser is pulled in that may be an issue as, since the fix of mentioned issue, no release was published (on GitHub).

EDIT: Clarified that Cypress' default browser is Electron and updated the note about that in the first paragraph. This also helped us to find a workaround: execute tests within our pipeline with another browser. In our case Chrome 145 works just fine, so would Firefos 148.