Not really.
Here is what I believe to be the situation with the latest version of Theia and the VS code extension
- the extension installs correctly within Theia, from OpenVSX
- most features work out of the box: syntax highlighting, code evaluation, plot pane, profiling flame graphs…
- the LanguageServer does not work out of the box (cf the issue mentioned above), but the extension can be patched to make it work (although it would be preferable if the fix would be implemented in Theia)
- the debugger does not work out of the box (but I didn’t spend too much time trying to make it work)
So our experience so far with Theia is that it is useable for Julia development (especially when patching the extension to make LanguageServer work with Theia), but not out of the box and not for all features.
We are currently in the process of migrating to code-server, which seems very promising so far.