Realm swift list using Decodable - swift

Question

I am trying figure out how could I pars Realm list using new feature in Swift 4, Decodable protocol.
Here is a example JSON:
[{
"name": "Jack",
"lastName": "Sparrow",
"number": "1",
"address": [
{
"city": "New York",
"street": "av. test"
}
]
},
{
"name": "Cody",
"lastName": "Black",
"number": "2"
},
{
"name": "Name",
"lastName": "LastName",
"number": "4",
"address": [
{
"city": "Berlin",
"street": "av. test2"
},
{
"city": "Minsk",
"street": "av. test3"
}
]
}]
And Realm Models:
Person
public final class Person: Object, Decodable {
#objc dynamic var name = ""
#objc dynamic var lastName = ""
var address = List<Place>()
override public static func primaryKey() -> String? {
return "lastName"
}
private enum CodingKeys: String, CodingKey { case name, lastName, address}
convenience public init(from decoder: Decoder) throws {
self.init()
let container = try decoder.container(keyedBy: CodingKeys.self)
self.name = try container.decode(String.self, forKey: .name)
self.lastName = try container.decode(String.self, forKey: .lastName)
self.address = try container.decodeIfPresent(List<Place>.self, forKey: .address) ?? List()
}
}
Place
public final class Place: Object, Decodable {
#objc dynamic var city = ""
#objc dynamic var street = 0
override public static func primaryKey() -> String? {
return "street"
}
// We dont need to implement coding keys becouse there is nothing optional and the model is not expanded by extra properties.
}
And the result of parsing this JSON would be:
[Person {
name = Jack;
lastName = Sparrow;
number = 1;
address = List<Place> <0x6080002496c0> (
);
}, Person {
name = Cody;
lastName = Black;
number = 2;
address = List<Place> <0x6080002496c0> (
);
}, Person {
name = Name;
lastName = LastName;
number = 4;
address = List<Place> <0x6080002496c0> (
);
As we can see our list are always empty.
self.address = try container.decodeIfPresent(List<Place>.self, forKey: .address) ?? List()
will always be a nil.
Also I am extending List by :
extension List: Decodable {
public convenience init(from decoder: Decoder) throws {
self.init()
}
}
Any ideas what might be wrong ?
EDIT
struct LoginJSON: Decodable {
let token: String
let firstCustomArrayOfObjects: [FirstCustomArrayOfObjects]
let secondCustomArrayOfObjects: [SecondCustomArrayOfObjects]
let preferences: Preferences
let person: [Person]
}
Each property (instead of token) is a type of Realm Object and the last one is the one from above.
Thanks!

Answer 1

You cannot go directly from your JSON to a List. What's in the JSON is an array. So this line won't work:
self.address = try container.decodeIfPresent(List<Place>.self, forKey: .address) ?? List()
You have to start by fetching the array:
if let arr = try container.decodeIfPresent(Array<Place>.self, forKey: .address) {
// arr is now an array of Place
self.address = // make a List from `arr`, however one does that
} else {
self.address = nil
}