I've added Prettier and its config, but haven't run it. It felt like we didn't have much discussion about code-styling. It'd be nice to gather opinions about it.

I actually was using Prettier via https://github.com/ijsto/eslint-config. I don't know what the best style for mxGraph is either, I figured the defaults looked pretty good even though it's not the styles I'd normally use and that they're pretty close to what I've seen in many JS projects like mapbox-gl etc. Should we add a hook so that it auto-cleans up to that style on commit?

I notice you've started converting some classes to functions too in mxEvents/mxUtils - looks much cleaner. I kept meaning to do it but to be honest knew the automatic typed-mxgraph documentation/types transfer scripts I was writing would depend on the code being in a class style convention. That's basically all done now, that script can be thrown away as far as I'm concerned and it's good to see them in there at last 😃

I see you've commented out some lines like

 import('../../../serialization/mxStylesheetCodec');

It's not ideal having these as "on-demand" loaders, but the reason for these kinds of lines being after the classes was because of circular imports with the XML encode/decode serializers (formerly in the io directory).

They used to be in the codecs themselves, but if importing the codecs with all of those encoders/decoders effectively tree-shaking isn't possible because the serializers depend on the original class and vice-versa.

There should be a better solution for this, so would be interested if anyone knows of one. I might ask this as an issue together with a note to check the xml serialization/deserialization example works and re-enable it when it does because at last check it went in an endless recursive loop.

the serializers depend on the original class and vice-versa.

I haven't yet tried, but if each codec gets registered into mxCodecRegistry wrapped in a function to be executed later, we might be able to dodge this circular dependency problem.

Other than codecs, mxUtils is importing too many classes and that created circular dependencies, so I splitted them a bit and also deleted some functions like eval, alert and so on.

I'm writing this outside based on my memory, so the names might be wrong ;)