How to implement decodeObjectOfClasses in Swift

Question

I'm having trouble finding the correct way to conform the the NSSecureCoding protocol in Swift, specifically when decoding objects that is an array of other objects.

I can't create an NSSet of class types in swift.

In Objective-C I would use

self.books = [aDecoder decodeObjectOfClasses:[NSSet setWithObjects:[NSArray class], [Book class], nil] forKey:@"books"];

in Swift I'm having issues creating the NSSet like this :

self.books = aDecoder.decodeObjectOfClasses(NSSet().setByAddingObject(NSArray.self).setByAddingObject(Book.self), forKey:"books")

Here's the error:

Type 'NSArray.Type' does not conform to protocol 'AnyObject'

Answer 1

For simple objects:

self.myObject = aDecoder.decodeObjectOfClass(MyObject.self, forKey: "myObject")!

Since Swift 3.0:

self.myObject = aDecoder.decodeObject(of:MyObject.self, forKey: "myObject")!

For nested objects:

NSSet(objects: [NSArray.self, Book.self])