In PharoJS, we are able to provide a placeholder for a class upon transpilation. So, if we know which class/method to replace, we have a tool.
But, we don't have a list of stuff requiring specific support/transpilation in PharoJS. And I didn't dig deep enough to list all missing stuff.
Yes, I'm lazy, I use TDD :-)
There's however few things we know are not support (yet) such thisContext is one of them (No idea how to handle it).
Process and related classes is another another bucket, though we have a plan for it.
Networking faces the same issues as graphics. We need to replace libraries. Note that, as for graphics we can use JS libraries, but we loose the benefit of pharo compatibility.
Noury