Diagnostics show up only after changing the file

[b-zee]

I'm curious if this is desired behavior. I am using VS Code and when opening a directory, I see no diagnostics initially. This only appears when opening a file and making a change to it (e.g. typing a character or removing).

Is there a way to get diagnostics for a whole workspace/directory? I see many useful diagnostics in files I'd like to fix, but I have to go through all files manually to do this.