visual studio code - VSCode Extension: Add document metadata when opening file

Question

I am building an extension that will open files from a remote server, but need to add some metadata into each document opened, which I will use later when the document is saved/closed.

Is there a way I can insert metadata into each document?

    vscode.workspace.openTextDocument(filePath + fileName).then(doc => {
        // Add some document specific metadata
        vscode.window.showTextDocument(doc);
    });

question from:https://stackoverflow.com/questions/65909532/vscode-extension-add-document-metadata-when-opening-file

Answer 1

I understand that VSC does that, for example storing the caret and scroll positions, or selection if any, and so on, retrieving it when you reopen the file.
I believe it does that by storing data outside of the files, otherwise it would alter their data, or it would need to manipulate metadata according to the local system (Windows, macOS, Linux, etc.), which is not obvious, if even possible.
On Windows, in C:Users<user name>AppDataRoamingCode, there are a number of databases which might fit this purpose, you can do a similar thing.