Change title of untitled tab in Visual Studio Code

Question

I\'m building a VS Code extension which includes changing the name/title of untitled-1 tab (unsaved file).
I tried running the below code in debugger consol

Answer 1

It's not possible - if you check out the source code for the API definition in vscode.d.ts, you'll see that fileName is declared as readonly:

export interface TextDocument {
    // ...
    readonly fileName: string;
    // ...
}

Unfortunately, it seems that the readonly attribute isn't reflected in the API docs on the website.