How to delete / skip directory using Angular schematics?

I have some files in my schematics template which should be generated only when a certain input options is present. e.g: db==true

Is there a way to skip these directories / files?

One solution is to remove them from the source using tree.delete(). However, that cannot remove dirs, only files.

What's the best way to do this:

What I want:

files/ - file1 - file2 - dir // only if db==true ...