Print certain font names

fontNames.swift

for familyName in UIFont.familyNames.sorted() {
    var hasPrintedFamilyName = false
    for fontName in UIFont.fontNames(forFamilyName: familyName).sorted() {
        let font = UIFont(name: fontName, size: 16.0)!
        guard font.fontDescriptor.symbolicTraits.contains(.traitMonoSpace) else { continue }

        if !hasPrintedFamilyName {
            print(familyName)
            hasPrintedFamilyName = true
        }
        print("    " + fontName)
    }
}