Swift 4: Codable dates

Swift4CodableDates.swift

import Foundation

struct LocationData: Codable {
    var city: String
    var country: String
    var address: String?
}

struct Item: Codable {
    var name: String
    var createdAt: Date
    var locationData: LocationData?

    enum CodingKeys: String, CodingKey {
        case name = "title"
        case createdAt = "created_at"
        case locationData
    }
}

let item = Item(
    name: "A test item",
    createdAt: Date(),
    locationData: LocationData(city: "London", country: "UK", address: nil)
)

let formatter = DateFormatter()
formatter.dateFormat = "EEEE, MMM d, yyyy"

let encoder = JSONEncoder()
encoder.dateEncodingStrategy = .formatted(formatter)

let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .formatted(formatter)

if let data = try? encoder.encode(item), let json = String(data: data, encoding: .utf8) {
    print("Encoded JSON:\n\t\(json)")
    if let ship = try? decoder.decode(Item.self, from: data) {
        print("\nDecoded class:\n\t\(ship)")
    }
}