let json = """ [{ "id": 0, "mode": "high" },{ "id": 1, "mode": "middle" },{ "id": 2, "mode": "moddle" },{ "id": 3, "mode": "low" }] """ enum Mode: String, Decodable { case high case middle case low } struct Object: Decodable { let id: Int let mode: Mode } let objects = try! JSONDecoder().decode([Object].self, from: json.data(using: .utf8)!) print(objects)

↑のような時に、Jsonのデコードを失敗とせずid:0,1,3のObjectの配列を返すような実装がしたい場合Arrayのラッパーみたいなものを書く感じになるのでしょうか？