How to manually decode an an array in swift 4 Codable?

Question

Here is my code. But I do not know what to set the value to. It has to be done manually because the real structure is slightly more complex than this example.

Any help please?

struct Something: Decodable {
   value: [Int]

   enum CodingKeys: String, CodingKeys {
      case value
   }

   init (from decoder :Decoder) {
      let container = try decoder.container(keyedBy: CodingKeys.self)
      value = ??? // < --- what do i put here?
   }
}

Answer 1

Your code doesn't compile due to a few mistakes / typos.

To decode an array of Int write

struct Something: Decodable {
    var value: [Int]

    enum CodingKeys: String, CodingKey {
        case value
    }

    init (from decoder :Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        value = try container.decode([Int].self, forKey: .value)
    }
}

---

But if the sample code in the question represents the entire struct it can be reduced to

struct Something: Decodable {
    let value: [Int]
}

because the initializer and the CodingKeys can be inferred.

Answer 2

Thanks for Joshua Nozzi's hint. Here's how I implement to decode an array of Int:

let decoder = JSONDecoder()
let intArray = try? decoder.decode([Int].self, from: data)

without decoding manually.