I do not understand this explicit vscode dependency. I can see monaco-languageclient also imports them.

I do not understand this explicit vscode dependency.

I see. They're from here: https://github.com/microsoft/vscode/blob/master/src/vs/vscode.d.ts#L8432-L8452.

Sorry for the sloppy initial commit. I've changed the ready resolution and added the missing dev dependency on @types/vscode.

I addressed your comments and re-implemented the workspaceFolder init/updated

@JanKoehnlein the build is failing, for some reasons it cannot find monaco namespace anymore

I had this sporadically here, too. I guess we should not add a dependency to @types/vscode but define the WorkspaceFolder and WorkspaceFolderChangeEvent interfaces ourselves

Thanks for the updates, @JanKoehnlein. Once the build is green I am going to verify it with one or two VS Code LS extensions.

It throws an error at startup:

monaco-workspace.ts:214 Uncaught (in promise) TypeError: Cannot read property 'map' of undefined
    at MonacoWorkspace.push.../../packages/monaco/lib/browser/monaco-workspace.js.MonacoWorkspace.updateWorkspaceFolders (monaco-workspace.ts:214)
    at MonacoWorkspace.<anonymous> (monaco-workspace.ts:200)
    at step (monaco-workspace.ts:15)
    at Object.next (monaco-workspace.ts:15)
    at fulfilled (monaco-workspace.ts:15)

You get the value before you set it:
Get:

Wow. Looks like I should get more sleep. Initialization of the property with an empty array was missing.

From the LSP specs:

The workspace/workspaceFolders request is sent from the server to the client to fetch the current open list of workspace folders. Returns null in the response if only a single file is open in the tool. Returns an empty array if a workspace is open but no folders are configured.

If I open Theia without a workspace and then open a single file (e.g.: main.go), the monaco-workspace returns with an empty array instead of null. Note, the LS works.

@kittaakos MonacoWorkspace confirms to VS Code API, not to LSP, transformation from VS Code api to LSP happens here: https://github.com/microsoft/vscode-languageserver-node/blob/50ffd38681b3fc8dde75a70accfa3c29db1889f3/client/src/workspaceFolders.ts#L45-L53

Docs for VS Code APIs: https://github.com/microsoft/vscode/blob/c975df3b59ac221f70d525498ae6ff81bce77a10/src/vs/vscode.d.ts#L8515-L8519

Although It says the same 😄 WorkspaceService has opened getter to check whether a folder is opened.

Thanks a lot for the reviews!