NSPredicate for filtering array of primitives field in Realm 3 - swift

Question

We have to store elements in Realm that have array of string field.
To do this we have to implement small workaround:
class RealmString: Object {
#objc dynamic var value = ""
override init(value: Any) {
super.init(value: [value])
}
required init(realm: RLMRealm, schema: RLMObjectSchema) {
super.init(realm: realm, schema: schema)
}
required init() {
super.init()
}
required init(value: Any, schema: RLMSchema) {
super.init(value: [value], schema: schema)
}
}
class Realm2Element: Object {
let tags = List<RealmString>()
}
As a result:
CONTAINS ALL OF condition looks like this:
ANY tags.value == "tag0" AND ANY tags.value == "tag1" AND ANY tags.value == "tag2"
CONTAINS ANY OF condition looks like this:
ANY tags.value IN {"tag0", "tag1", "tag2"}
Realm3 suppors array of primitives. We removed .value keyPath from condition. But we have got error when applied these filters for Realm3Element:
class Realm3Element: Object {
let tags = List<String>()
}
For CONTAINS ALL OF condition:
'Invalid value', reason: 'Expected object of type (null) for property 'tags' on object of type 'Realm3Element', but received: tag0'
For CONTAINS ANY OF condition:
'Expected object of type (null) in IN clause for property 'tags' on object of type 'Realm3Element', but received: tag0'
We run through the all possible variations, but couldn't find any solution.
Does Realm3 support filtering by array of primitives field?

Answer 1

You can't achieve your goals using predicate with Realm because Realm have a lot of limitations using Predicates but you can use this way as a workaround
let filterArray = ["tag0","tag1"]
Array(realm.objects(Realm3Element.self)).filter({$0.tags.sorted().joined().contains(filterArray.sorted().joined())})
If you want a perfect solution tracking this issue #5334