MongoDB Realm Swift SDK

class CoffeeDrink: Object {
    @Persisted var name = ""
    @Persisted var hotOrCold: String?
    @Persisted var rating = 0
}

let realm = try! Realm()
try! realm.write {
    // Add coffee shop and drink info here.
    let shop = CoffeeShop()
    shop.name = "Better Coffee"
    let drink = CoffeeDrink()
    drink.name = "Maple Latte"
    drink.rating = 7
    shop.drinks.append(drink)
    realm.add(shop)
}

let realm = try! Realm()
let drinks = realm.objects(CoffeeDrink.self)
let highlyRatedDrinks = drinks.where {
    $0.rating > 6
}
print("Highly-rated drinks: \(highlyRatedDrinks.count)")
let mapleOrCaramelLattes = drinks.where {
    $0.name == "Maple Latte" || $0.name == "Caramel Latte"
}
print("Number of maple or caramel lattes: \(mapleOrCaramelLattes.count)")
let drinkTempNotSpecified = drinks.where {
    $0.hotOrCold == nil
}
print("No info about drink temp: \(drinkTempNotSpecified.count)")

let realm = try! Realm()
// Get a maple latte
let mapleLatte = realm.objects(CoffeeDrink.self).where {
    $0.name == "Maple Latte"
}.first!
// Open a thread-safe transaction
try! realm.write {
    // Change the name of the maple latte.
    mapleLatte.name = "Maple Delight"
    // Specify that the maple latte is a hot drink.
    mapleLatte.hotOrCold = "Hot"
} // When the transaction completes, the drink details are updated in the database.

var drinkNotificationToken: NotificationToken?
func objectNotificationExample() {
    // Create a new drink
    let drink = CoffeeDrink()
    drink.name = "Spicy Icy Coffee"
    drink.rating = 9
    // Open the default realm.
    let realm = try! Realm()
    try! realm.write {
        // Add the drink to the realm
        realm.add(drink)
    }
    // Observe changes.
    drinkNotificationToken = drink.observe { change in
        switch change {
        case .change(let object, let properties):
            for property in properties {
                print("Property '\(property.name)' of object \(object) changed to '\(property.newValue!)'")
            }
        case .error(let error):
            print("An error occurred: \(error)")
        case .deleted:
            print("The object was deleted.")
        }
    }
    // Now, when you update the object, this triggers the notification
    try! realm.write {
        drink.name = "Ancho Chili Chocolate Iced Coffee"
    }
}

// Open the default realm.
let realm = try! Realm()
// Create a couple of references to a single underlying coffee drink object
let drinkA = realm.objects(CoffeeDrink.self).where {
    $0.name == "Maple Latte"
}.first!
let drinkB = realm.objects(CoffeeDrink.self).where {
    $0.name == "Maple Latte"
}.first!
// Update drink A's name
try! realm.write {
    drinkA.name = "Maple-iest Latte in Town"
}
// See that drink B instance updates with the new name
XCTAssert(drinkA.name == drinkB.name)
// Update drink B's rating
try! realm.write {
    drinkB.rating = 4
}
// See that drink A instance updates with the new rating
XCTAssert(drinkB.rating == drinkA.rating)