Support for didChangeWatchedFiles workspace method

[corneliusweig]

The language server protocol defines the didChangeWatchedFiles workspace method to notify the language server about changes in files that are part of the workspace, but not currently opened. It is encouraged to support this method, to reduce the number of processes that watch for files and thus unnecessarily use more system resources.

My understanding is that typescript-language-server currently uses the node file watching APIs of the underlying tsserver to watch for such file changes, which ignores this protocol method. Are there plans to support the didChangeWatchedFiles method in the future? Or are there fundamental obstacles that make this impossible?

[rchl]

As you said, currently tsserver does the file watching.

Typescript's code is massive and what it watches exactly and when is not documented anywhere so:

• moving that logic to the typescript-language-server's side would be major undertaking
• I don't believe there is an API to notify tsserver about unopened file being changed (though I haven't researched much)
• I haven't even seen an option to disable tsserver's own file watching.

So I would say that the way it works now is "as designed" and it's not really viable to change that.

[corneliusweig]

Ok, thanks for the clarification.