saveLoad.swift

    static func saveToFile(friends: [Friend]) {
        let plistName = "friends"

        let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        let archiveURL = documentsDirectory.appendingPathComponent(plistName).appendingPathExtension("plist")
        
        let propertyListEncoder = PropertyListEncoder()
        let encodedFriends = try? propertyListEncoder.encode(friends)
        
        try? encodedFriends?.write(to: archiveURL, options: .noFileProtection)
    }
    
    static func loadFromFile() -> [Friend]? {
        let plistName = "friends"
        
        let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        let archiveURL = documentsDirectory.appendingPathComponent(plistName).appendingPathExtension("plist")
        
        let propertyListDecoder = PropertyListDecoder()
        
        guard let retrievedFriendsData = try? Data(contentsOf: archiveURL) else { return nil }
        guard let decodedFriends = try? propertyListDecoder.decode(Array<Friend>.self, from: retrievedFriendsData) else { return nil }
        return decodedFriends
    }