@sam and all interested in typing math in Discourse. I’ve updated the discourse-math plugin so that it uses MathJax V3, rather than the much slower and very outdated V2. As expected, the result is a much snappier user experience, while still maintaining the feature rich environment as compared to KaTeX. I’d love to issue a pull request, if you think the results look good. You can see it in action on my class Discourse site: [תמונה] Discourse at Mark's Math A forum for Mark's students to talk about math Most of the content on that site is private or unlisted. There should be several topics at the top in the MathJax V3 category that illustrate the ideas, though You can examine the code for the plugin in this standalone discourse-mathjax plugin repo. The file that has the most modifications by far is the initializer. You can also use that repo to install it on a standalone site right now. Just be sure to remove the old repo during installation. Thus, you’d modify the standard plugin install technique to look like this: hooks: after_code: - exec: cd: $home/plugins cmd: - rm -r discourse-math - git clone https://github.com/discourse/docker_manager.git - git clone https://github.com/mcmcclur/discourse-math.git Comments The most recent version of MathJax is actually 4.0.0. I chose to go with V3.2.2 for several reasons While V4 is certainly much faster than V2, it’s not quite as fast as V3. The user experience is a bit different in V4, particularly if the user clicks on the output. The 4.0.0 status makes me wonder how many bugs there might be. Having said that, the API for V4 is identical to that of V3. It should be possible to upgrade later, by simply dropping the latest MathJax Repo in. I had to make one small change in the locales/server.en.yml file. Of course, there are a ton more such files for various languages. My understanding is that those other files would be automatically translated later? I really don’t use chat at all and haven’t tested it in that context.

[תמונה] sam: Absolutely, code will be very helpful here, perhaps fork discourse and then push your changes to a branch, then I can pull changes from your branch into the PR. OK, here is the code: https://github.com/mcmcclur/discourse/tree/mathjax-mcmcclur Beware, though, I did not work directly from your latest commit. I started directly from Discourse main and made changes from there. Thus, I learned a fair amount from your work but the overall structure is different. I think you could summarize the main difference as follows: Where you (naturally) use Discourse features inherited from Ember to coordinate the timings associated with things like loading and typesetting, I use MathJax features. Thus, my load-mathjax and mathjax bundles (one for svg and one for chtml) are much simpler than yours. The loading is all coordinated via the window.MathJax object in discourse-math-mathjax. I still have the same problem that I described before, namely that this commented out loader doesn’t work; I’ve got to use this CDN version instead. I really don’t know why. I think that your code suffers from the same problem. That’s why AsciiMath doesn’t seem to work.

[תמונה] mcmcclur: I think that your code suffers from the same problem. That’s why AsciiMath doesn’t seem to work. can you double check my latest commit, I think I added a funnel for ember so now the ember build puts all the files in the right place.

[תמונה] sam: can you double check my latest commit, I think I added a funnel for ember so now the ember build puts all the files in the right place. OK, I’ve got some very good news and some frustrating news. First, you’re absolutely right that adding the funnel places those files in the correct place. I added the funnel to my branch and it now works great without the CDN dependancy. :tada: Unfortunately, I am unable to run your code at the moment. Whenever I navigate to a page with math on it, the math does not typeset and I see the following error message in the console: Uncaught (in promise) Error: State EXPLORER already exists I’m certain I had your code working before so I suppose it’s something I did. To be clear, though, I literally started an entirely fresh directory using the techniques described in Install Discourse on macOS for development. git clone https://github.com/discourse/discourse.git ./discourse cd ./discourse bundle install pnpm install bundle exec rake db:create bundle exec rake db:migrate RAILS_ENV=test bundle exec rake db:create db:migrate # In one terminal bundle exec rails server # In another terminal bin/ember-cli I then grabbed your code with git checkout 71ad0305f812311f2a4570edf7c33f97de46c457 git switch -c mathjax-sam Even from that fresh setup, I get the error. At this point, I’m pretty happy with my version of the code but still curious about what’s going on with yours. I need to take a break from this for the holiday, though. I’m happy to take another look at it in a few days time. One final point, though: As far as I know, await import("tex-mml-chtml.js") // followed by await import("input/asciimath.js") shouldn’t work, which is effectively what your code is doing, I think. I’m being imprecise with paths there but my point is that I don’t know that consecutive dynamic calls to import lead to the correct MathJax structure. I think that loading MathJax components is pretty complicated and that’s why they’ve got such a detailed loading process with the MathJax object and all. Thanks so much for your help and patience @sam!

Been making progress here: [image] I moved the giant javascript payloads into a dedicated gem https://github.com/discourse/discourse_math_bundle/ This will make it significantly easier to stay up to date, plus mathjax is not longer checked in to the reop.

[תמונה] sam: Been making progress here: Hey Sam - I’ve been playing with this quite a lot today. It looks great! I do think there’s still quite a lot to do, though. Some of it, I can definitely help with. Some of it is possibly beyond my capacity, particularly with my university starting back up. Anyways, here are a few of my thoughts. Zoom Zoom on hover is no longer available in MathJax V4. It’s easy to set it to zoom on alt-click, though. I’ve done so here: https://github.com/mcmcclur/discourse/compare/5ad3add3a4b2823be3b325f3571a492f14255759...c8b4a636e828a7a401a846a160deeaa5af734ece Note that there’s a known MathJax bug that needs to be addressed with a little CSS, as described in this GitHub Issue. I’ve included that fix in this code as well. Loading options As it stands, AsciiMath cannot be turned on and Accessibility cannot be turned off. I think that’s down to the way that submodules are loaded sequentially inload-mathjax.js. As I stated in my last message, it’s much more common to pre-define a window.MathJax object that specifies which components you want. The MathJax object is redefined when the main script is loaded. That’s how I was able to get this working in my V3 version. I think I could incorporate that approach in your code base during the first part of next week, if you’d like me to try? Once we get options figured out, it might also be worth considering if there are new options available in V4 that should be included. The rich editor This is just great - I’m super happy to see it! I wonder if it would be possible to get a sparkly AI context menu available within the modal? I ask because students (and professors :confused:) sometimes have difficulty typing LaTeX. A little AI proofreader can make that so much smoother. I’ve incorporated that into my classroom Discourse and am looking forward to using it this coming semester. OK, I’m sure there’s a lot more, but I’m about done for the day. Thanks so much!!! :rocket: :fire: :tada:

I understand that the discourse-math plugin relies on the separate MathJax/KaTeX asset gem rather than vendoring those libraries directly, which keeps the plugin lightweight and allows the math libraries to be updated independently. I’d like to help validate this ahead of the first production release by doing some real-world testing. My initial thought was to spin up a separate, disposable instance and enable the plugin there to test math-heavy content, asset loading via the standard pipeline, CSP behaviour, and performance. Before doing so, I wanted to ask what the recommended environment is at this stage - whether early testing in a production-like setup l is appropriate, or whether you’d prefer this to be done using a development environment until the first production release. I’m very happy to test in whichever way is most useful and to report any issues or edge cases I encounter upstream. I can’t commit to a fixed testing schedule due to university commitments, but I’m happy to do best-effort testing when time allows, and I’m likely to have significantly more availability after 6 June.

I’ve got the options working well, now; you can see the code here: https://github.com/mcmcclur/discourse/compare/5ad3add3a4b2823be3b325f3571a492f14255759...ad6c3fa877632eba40cd83d1534aaa0d5dd6dc8d Here are a few comments: All configuration and loading is handled by the MathJaxInitConfig obect defined in math-renderer.js. I removed a fair amount of inert code from load-mathjax.js. The ‘ui/safe’ extension is always loaded. I’ve added a “Discourse math enable menu” option, which is true by default. When false, this removes the menu entirely, which makes MathJax even speedier. The next two menu items are Discourse math zoom on click and Discourse math enable accessibility. These have no effect if the menu is disabled but are independent of one another when it is enabled. The whole menu looks like so: [Screenshot 2026-01-03 at 4.01.03 PM] I’ve not added any tests just yet but could give it a try, if you’d like a pull request.

Here, by the way, is an example of mathematical proofreading via AI in this development version in action: [ProofreadMathAI] The user can optionally highlight a specific mathematical expression in the markdown editor and request that it be proofread. It might be nice to have that as an option in the new math editor.

@sam It turns out that KaTeX isn’t working quite right in the new plugin. If you take a look at it, it’s quite clearly a missing font problem and, indeed, the console indicates that there a bunch of font (Woff-v2) files that are not found. The fonts actually exist in the correct location, which should be in a folder named ‘fonts’ adjacent to the style sheet. Both of these files exist on my development version, for example: http://localhost:4200/plugins/discourse-math/katex/katex.min.css and http://localhost:4200/plugins/discourse-math/katex/fonts/KaTeX_Size2-Regular.woff2 When we take a look at the Network tab of the console, it appears that it’s trying to download something like http://localhost:4200/t/my-topic/fonts/KaTeX_Size2-Regular.woff2 Thus, the browser is looking in a ‘fonts’ folder adjacent to the topic URL, which is clearly wrong. I suppose this all has something to do with the loadKaTeX function defined in the katex-bundle, which I guess loads KaTeX in a non-standard way leading to KaTeX not really knowing where the CSS file lives. I don’t know how to fix it, though.

Thanks so much Mark, I went ahead and merged your commits, will have a look at the Katex thing toda [תמונה]Discourse Math Here, by the way, is an example of mathematical proofreading via AI in this development version in action: Is this just via a custom prompt for the proofreader persona? [תמונה] Ethsim2: Before doing so, I wanted to ask what the recommended environment is at this stage - whether early testing in a production-like setup l is appropriate, or whether you’d prefer this to be done using a development environment until the first production release. I would not worry about it, Mark and I have this under control.

Upgrading Mathjax to version 4

מפתח

sam (Sam Saffron) 4 בינואר,‏ 2026,‏ 10:00pm 26

I just pushed a fix for Katex, let me know if it works, I need to run it by @david to confirm it is safe, our pattern for loading CSS is not compatible with relative links inside the CSS file cause we are embedding a stylesheet

נושא		תגובות	צפיות
Upgrading to New Math Plugin Product Support math	11	815	18 במאי,‏ 2022
A new release of Discourse Math Announcements math	2	363	18 בינואר,‏ 2026
Discourse Math Plugin official , math , included-in-core	9	38895	11 ביולי,‏ 2026
MathJax plugin could not find module discourse/lib/load-script Product Support	5	1731	17 במרץ,‏ 2015
Plugin not work and show Product Support	8	3192	15 ביולי,‏ 2017

Upgrading Mathjax to version 4

נושאים קשורים