This happens when I try to open a .json file for editing. I get a notification saying “Failed to start JSON language server: Request initialize failed with message: Cannot read property ‘provideFormatter’ of undefined”. I believe I get this whether or not i have the @theia/json package in my package.json.
Any ideas what the problem is? I’m sure it’s something simple like a missing package dependency or configuration setting, but for the life of me I can’t figure it out.
[original thread by Joseph Chu]
Hi @joechu, the issue you described seems to be the same as https://github.com/eclipse-theia/theia/issues/6393 which has been resolved in https://github.com/eclipse-theia/theia/pull/6398. It will be included in the next release 
If you point your dependencies to next instead of latest you should also see the fix. I hope this helps!
[Joseph Chu]
Thanks for your help! This should have been something that I could have found myself, but for some reason just didn’t come up in my search results. I didn’t have any luck resolving this pointing my dependencies to next, but have confirmed that this has been fixed in 0.12.0!
It should be fixed now the latest release was yesterday, and no problem!