Generating slides: Chrome and Edge can't stand the use of --reveal-prefix

Greetings anyone and everyone.

I’ve also posted about the following problem on GH to no avail.

I want to convert notebooks to reveal.js slides. I need to use a custom reveal.js theme. This means a local reveal.js directory until I setup my own CDN. This is done with nbconvert option --reveal-prefix

Unfortunately, Chrome and MS Edge cease being able to display the resulting files via JupyterLab as soon as slides are generated with option --reveal-prefix. When loading, these browsers report CORS-related errors. Firefox is ok. Of course loading the same file outside of JLab, with any browser, works.

Errors look like this (multiple instances):

Cross-Origin Read Blocking (CORB) blocked cross-origin response http://localhost:8888/login?next=%2Ffiles%2Fwork%2Fme%2Freveal.js%2Fdist%2Freveal.css with MIME type text/html. See for more details.

The offending line that corresponds to the above error is generated like this:

 grep dist/reveal.css /opt/conda/share/jupyter/nbconvert/templates/reveal/index.html.j2
<link rel="stylesheet" href="{{ reveal_url_prefix }}/dist/reveal.css">
  • The output file is unusable under JupyterLab (http://localhost:8888/), except if using Firefox, where everything is fine.
  • Removing option --reveal-prefix allows viewing the files normally under Chrome or MS Edge.
  • Adding option --post serve allows allows viewing the files normally under Chrome or MS Edge using the dedicated URL (http://localhost:8000)
  • Funnily, hacking the HTML page and adding the identification token fixes the issue with Chrome or MS Edge:
$ grep -A1 -B1 token slides-test-hack.slides.html 
<!-- General and theme style sheets -->
<link rel="stylesheet" href="reveal.js/dist/reveal.css?token=b28ca9b1b7c3ad0cdb61622b682b47ffd74518cb47796314">

    <!-- End of mathjax configuration --><!-- Reveal Theme -->
<link rel="stylesheet" href="reveal.js/dist/theme/mytheme.css?token=b28ca9b1b7c3ad0cdb61622b682b47ffd74518cb47796314" id="theme">


I’ve nothing against Firefox, but does anyone know how to make themed slides generated in JupyterLab viewable in JupyterLab?