Swift Decodable With Multiple Custom Dates

RSSFeed.swift

import Foundation

extension DateFormatter {
    static let iso8601Full: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZZZZZ"
        formatter.calendar = Calendar(identifier: .iso8601)
        formatter.timeZone = TimeZone(secondsFromGMT: 0)
        formatter.locale = Locale(identifier: "en_US_POSIX")
        return formatter
    }()
    
    static let yyyyMMdd: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd"
        formatter.calendar = Calendar(identifier: .iso8601)
        formatter.timeZone = TimeZone(secondsFromGMT: 0)
        formatter.locale = Locale(identifier: "en_US_POSIX")
        return formatter
    }()
}

public struct RSSFeed: Codable {
    public struct Feed: Codable {
        public struct Podcast: Codable {
            public let name: String
            public let artistName: String
            public let url: URL
            public let releaseDate: Date
        }
        
        public let title: String
        public let country: String
        public let updated: Date
        public let podcasts: [Podcast]
        
        private enum CodingKeys: String, CodingKey {
            case title
            case country
            case updated
            case podcasts = "results"
        }
    }
    
    public let feed: Feed
}

public typealias Feed = RSSFeed.Feed
public typealias Podcast = Feed.Podcast

extension Podcast {
    public init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        name = try container.decode(String.self, forKey: .name)
        artistName = try container.decode(String.self, forKey: .artistName)
        url = try container.decode(URL.self, forKey: .url)
        let dateString = try container.decode(String.self, forKey: .releaseDate)
        let formatter = DateFormatter.yyyyMMdd
        if let date = formatter.date(from: dateString) {
            releaseDate = date
        } else {
            throw DecodingError.dataCorruptedError(forKey: .releaseDate, in: container, debugDescription: "Date string does not match format expected by formatter.")
        }
    }
}

let json = """
{
"feed": {
"title":"Top Audio Podcasts",
"country":"gb",
"updated":"2017-11-16T02:02:55.000-08:00",
"results":[
{
"artistName":"BBC Radio",
"name":"Blue Planet II: The Podcast",
"releaseDate":"2017-11-12",
"url":"https://itunes.apple.com/gb/podcast/blue-planet-ii-the-podcast/id1296222557?mt=2"
},
{
"artistName":"Audible",
"name":"The Butterfly Effect with Jon Ronson",
"releaseDate":"2017-11-03",
"url":"https://itunes.apple.com/gb/podcast/the-butterfly-effect-with-jon-ronson/id1258779354?mt=2"
},
{
"artistName":"TED",
"name":"TED Talks Daily",
"releaseDate":"2017-11-16",
"url":"https://itunes.apple.com/gb/podcast/ted-talks-daily/id160904630?mt=2"
}
]
}
}
"""

let data = Data(json.utf8)
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .formatted(DateFormatter.iso8601Full)
let rssFeed = try! decoder.decode(RSSFeed.self, from: data)

let feed = rssFeed.feed
print(feed.title, feed.country, feed.updated)

feed.podcasts.forEach {
    print($0.name)
}