_SwiftのJSONDecoderを試す.md

swift json decode

Run

swift --version
Apple Swift version 5.2.4 (swiftlang-1103.0.32.9 clang-1103.0.32.53)
Target: x86_64-apple-darwin19.5.0

swift main.swift
A(a: main.B(b: "xxx", c: 2020-07-08 06:00:00 +0000, d: nil, e: [main.B.E.HOGE, main.B.E.FUGA, main.B.E.PIYO]))
A(a: main.B(b: "xxx", c: 2020-07-08 06:00:00 +0000, d: nil, e: [main.B.E.HOGE, main.B.E.FUGA, main.B.E.PIYO]))

Refference

• enum
  • https://medium.com/@bj1024/swift4-codable-enum-e78b341cc5ba
• Date
  • https://qiita.com/takasek/items/b2b0e3849e204037d2de

main.swift

import Foundation

let data = """
{
    "a": {
        "b": "xxx",
        "c": "2020-07-08T15:00:00+09:00",
        "d": null,
        "e": [
            "hoge",
            "fuga",
            "piyo"
        ]
    }
}
""".data(using: .utf8)!

struct A: Decodable { 
    let a: B
}

struct B: Decodable {
    let b: String
    let c: Date
    let d: Optional<Int>
    let e: Array<E>

    enum E: String, Decodable {
        case HOGE = "hoge"
        case FUGA = "fuga"
        case PIYO = "piyo"
    }
}

let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .iso8601
let t1  = try decoder.decode(A.self, from: data)
print(t1)

decoder.dateDecodingStrategy = .formatted({
        let f = DateFormatter()
        f.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZ"
        return f
        }())
let t2  = try decoder.decode(A.self, from: data)
print(t2)