How to create decodable of nested array in swift?

October 7, 2022

Background: I’m using swift Alamofire@5.6.2 and I need to parse json data

AF.request("https://xxx.json").validate().responseDecodable(of: Decodable)

The data looks like:

[
   [
       "a",
       123,
       1.0,
   ],
   [
       "b",
       456,
       2.0,
   ],
]

My code (this is the wrong way):

struct Item: Codable {
   var name: String
}

...responseDecodable(of: [Item].self)

Should I use enum instead? I read some similar answers but they all have keys at some point, my data is pure array without keys.

>Solution :

Assuming the types are always the same in the same order this is a simple example how to decode the inner array, the struct member names are arbitrary

struct Item: Decodable {
    let name: String
    let someInt: Int
    let someDouble: Double
    
    init(from decoder: Decoder) throws {
        var container = try decoder.unkeyedContainer()
        name = try container.decode(String.self)
        someInt = try container.decode(Int.self)
        someDouble = try container.decode(Double.self)
    }
}

and decode [Item].self