Saving and loading products with NSUserDefaults

gistfile1.swift

class ProductManager {
    
    var products : [Product] = []
    
    var productsKey : String = "products"
    
    let userDefaults = NSUserDefaults.standardUserDefaults()
    
    func saveProductsToDefaults() {
        let productsKeyedArchive = NSKeyedArchiver.archivedDataWithRootObject(self.products)
        self.userDefaults.setObject(productsKeyedArchive, forKey: productsKey)
    }
    
    func loadProductsFromDefaults() {
        if let data = self.userDefaults.objectForKey(productsKey) as? NSData {
            let unarc = NSKeyedUnarchiver(forReadingWithData: data)
            if let savedProducts = unarc.decodeObjectForKey("root") as? [Product] {
                self.products = savedProducts
            }
        }
    }
}