MacOS how is KIND implemented - swift

Question

I am trying to write a piece of code that instead of checking file extensions for the many different types of image files, but instead looking at the file attributes. What I can’t figure out from searching the docs is if KIND:Image is really a file attribute or simply a construct Apple created in the FinderApp to make things easier for the user.
I wrote a snippet that pulls the attributes for files with an extension of jpeg and for each file the fileType is returned as NSFileTypeRegular.
let attr = try filemanager.attributesOfItem(atPath: pathConfig+"/"+file) as NSDictionary
if file.hasSuffix(ext) {
   print ("Adding \(file) [ \(attr.fileSize()) \(attr.fileType())]")
   print ( attr.fileModificationDate() )
}
Does anybody know if MacOS retains an attribute for the category a file falls in to. e.g. IMAGE, DOCUMENT etc.

Answer 1

To achieve a functionality similar to the Kind search tag in Finder you can use UTType (Link to reference).
You can get the UTType of a file by initialising it with the file extension:
let fileType = UTType(filenameExtension: fileURL.pathExtension)
The cool thing about UTTypes is that they have a hierarchy, for example, UTType.jpeg is a subtype of UTType.image, along with others like .png.
If you want to check if a file is any kind of image, you can do it like this
let isImage = fileType.conforms(to: .image)
You can check the list for the kind of types you want to support as "Kinds", and filter using those UTTypes

Answer 2

This was my final solution based on the information provided by #EmilioPelaez I am not completely comfortable with Swift especially the unwrapping operations so if the code looks weird that might be why.
func imagesInDir(path: String?) -> [String] {
if let path {
let filemanager: FileManager = FileManager()
let files = filemanager.enumerator(atPath: path)
var array = [String]()
var urlFile: NSURL
while let file = files?.nextObject() as? String {
urlFile = NSURL(fileURLWithPath: file, isDirectory: false)
if (urlFile.isFileURL) {
if let pathExt = urlFile.pathExtension {
if let fileType = UTType(filenameExtension: pathExt) {
let isImage = fileType.conforms(to: .image)
if (isImage){
array.append(file)
print ("\(array.count) \(fileType)")
}
}
}
}
}
}
return array
}