Rewrite IsParentOfChild

csharp/App/Backend/Database/Folder.cs

@@ -26,7 +26,6 @@ public partial class Db
         return Folders.Where(f => f.ParentId == parent.Id);
     }
     
-    
     public IEnumerable<Folder> GetDescendantFolders(Folder parent)
     {
         return parent.Traverse(GetChildFolders);

csharp/App/Backend/Database/User.cs

@@ -30,17 +30,10 @@ public partial class Db
 
     public Boolean IsParentOfChild(User parent, User child)
     {
-        var parentPointer = child.ParentId;
-
-        if (parent.Id == child.Id)
-            return true;
-
-        while (parentPointer != null && parentPointer != parent.Id)
-        {
-            parentPointer = GetUserById(parentPointer).ParentId;
-        }
-
-        return parentPointer == parent.Id;
+        return child
+              .Unfold(u => GetUserById(u.ParentId))
+              .Select(u => u.Id)
+              .Contains(parent.Id);
     }
 
     public User? GetUserByEmail(String email) => Users.FirstOrDefault(u => u.Email == email);