Filter Embedded Object List

MongoDB Atlas App Services & Realm Realm
1

We have a use case where we need to filter on a List of Embedded objects before they are stored in Realm. Doing this throws an error

This method may only be called on RLMArray instances retrieved from an RLMRealm

Given a PersonClass object and an EmbeddedAddress embedded object

class PersonClass: Object {
   @objc dynamic var name = ""
   let addressList = List<EmbeddedAddress>()
}

class EmbeddedAddress: EmbeddedObject {
   @objc dynamic var name = ""
}

here’s the code that crashes

let person = PersonClass()
person.name = "Ted"

let a = EmbeddedAddress()
a.name = "a"

let b = EmbeddedAddress()
b.name = "b"

let c = EmbeddedAddress()
c.name = "c"

person.addressList.append(objectsIn: [a, b, c])

for addr in person.addressList {
   print(addr.name) // prints a, b, and c
}

let result = person.addressList.filter("name == 'b'") //CRASH

The use case is a user creates a person and as addresses are being added, we want to ensure they are unique before saving so we need to filter to see if the entered address was already entered.

2

Hi @Jay

This is the intended behaviour. If you intend to use a collection of Realm Results then you must add the object to the Realm.

3

Thank you @Lee_Maguire

Does that mean Realm provides no filtering for a List of Embedded objects - that will need to be done using Swift only?

4

We provide filtering as long as your person object is managed. Otherwise you can use the Swift Foundation filter function.

5

Thanks @Lee_Maguire

Perhaps I am looking at this incorrectly but the following code to get the first match for Addr 10 won’t compile

if let foundAddr = person.addressList.filter { $0.name == "Addr 10" }.first {
    print(foundAddr)
}

Anonymous closure argument not contained in a closure

However, if I do this with a non-embedded object, it works fine.

6

@Lee_Maguire

Any thoughts or suggestions on the above?