In my case let’s say I have a specific extension .new and I want a context menu item to appear only in folders containsing files with that extension, how can I do it?

/folderA
  /folderB   <--- context menu should appear here
    /cool.new  

I’ve tried with regex but VScode is not happy

      "explorer/context": [
        {
          "command": "extensionName/my-command",
          "when": "resourceFilename =~ /.+/.+\.new$/"
        }
      ]