Extension loaded via autoload may not be available in time when ui/lazy is also loaded

[AlexEdgcomb]

Issue Summary

An extension (e.g., cancel) that is loaded via autoload may not be available in time when ui/lazy is also loaded, leading to the typeset showing the macro name in red, like \cancel.

Steps to Reproduce:

1. Go to https://codepen.io/alexedgcomb/pen/KKEgLOJ
2. Refresh if typesetting worked
   Observed: About 1 in 5 page refreshes, the cancel package is not found before typesetting

I tried to reduce the config as much as possible. Seems that each of the remaining pieces is necessary to produce the issue.

Technical details:

• MathJax Version: 4.0.0-beta.3
• Client OS: Mac OS 13.4
• Browser: Firefox 121.0.1

I am using the following MathJax configuration:

MathJax = {
  loader: { load: [ 'ui/lazy' ] },
  options: { lazyAlwaysTypeset: '.disable-lazy-typesetting' },
  output: { font: 'mathjax-tex' },
};

and loading MathJax via

<script src="https://cdn.jsdelivr.net/npm/[email protected]/tex-mml-svg.js"></script>

I am using a delayed call to both add content and typeset:

async function typeset() {
  document.getElementById('test').innerHTML = '<div class="disable-lazy-typesetting"><p>\\( \\cancel{x} \\)</p></div>';
  await MathJax.startup.promise;
  MathJax.typesetPromise([ document.getElementById('test') ]);
}

setTimeout(typeset, 10);

Supporting information:

• Also sometimes happens in:
  • MJ4.0.0-alpha.1 https://codepen.io/alexedgcomb/pen/zYbKQVY
  • Chrome 120.0.6099.216 (Official Build) (arm64)
• No console errors/warnings
• A simple workaround is to add the needed extensions (e.g., cancel) to the configuration. No less, I thought y'all might appreciate this report :)

[dpvc]

This turns out to be an issue with how MathJax.startup.promise is resolved, and is a duplicate of #3130.

You can work around it by adding

    startup: {
      pageReady() {
        const config = MathJax.config.startup;
        const output = MathJax.config.output;
        return (config.loadAllFontFiles && output.font ? output.font.loadDynamicFiles() : Promise.resolve())
          .then(config.typeset && MathJax.typesetPromise ?
                () => MathJax.startup.typesetPromise(config.elements) : Promise.resolve);
      }
    }

to your Mathjax configuration for now.

BTW, I do get a console error about null not having a parentNode, so I'm not sure why you aren't seeing that.

[AlexEdgcomb]

@dpvc , thank you! Works wonderfully.

BTW, I do get a console error about null not having a parentNode, so I'm not sure why you aren't seeing that.

Doh, I do see that. Not sure how I missed that... Definitely would have helped me find #3130 on my own!

[dpvc]

Doh, I do see that. Not sure how I missed that... Definitely would have helped me find #3130 on my own!

No problem. I'm just glad it wasn't something that I had to fix. :-)