Swift 4 Codable: Converting JSON return String to Int/Date/Float

Question

I\'m going through some projects and removing JSON parsing frameworks, as it seems pretty simple to do with Swift 4. I\'ve encountered this oddball JSON return where I

Answer 1

public extension KeyedDecodingContainer {
public func decode(_ type: Date.Type, forKey key: Key) throws -> Date {
    let dateString = try self.decode(String.self, forKey: key)
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "MM/dd/yyyy hh:mm:ss a"
    guard let date = dateFormatter.date(from: dateString) else {
        let context = DecodingError.Context(codingPath: codingPath,
                                            debugDescription: "Could not parse json key to a Date")
        throw DecodingError.dataCorrupted(context)
    }
    return date
}
}

Usage: -

let date: Date = try container.decode(Date.self, forKey: . createdDateTime)

Answer 2

This is not yet possible as Swift team has provided only String to date decoder in JSONDecoder.

You can always decode manually though:

struct WaitTimeContainer: Decodable {
    let waitTimes: [WaitTime]

    private enum CodingKeys: String, CodingKey {
        case waitTimes = "WaitTimes"
    }

    struct WaitTime:Decodable {
        let checkpointIndex: Int
        let waitTime: Float
        let createdDateTime: Date

        init(checkpointIndex: Int, waitTime: Float, createdDateTime:Date) {
            self.checkpointIndex = checkpointIndex
            self.waitTime = waitTime
            self.createdDateTime = createdDateTime
        }

        static let formatter: DateFormatter = {
            let formatter = DateFormatter()
            formatter.calendar = Calendar(identifier: .iso8601)
            formatter.locale = Locale(identifier: "en_US_POSIX")
            formatter.timeZone = TimeZone(secondsFromGMT: 0)
            formatter.dateFormat = "MM/dd/yyyy hh:mm:ss a"
            return formatter
        }()

        init(from decoder: Decoder) throws {
            let container = try decoder.container(keyedBy: CodingKeys.self)
            let checkpointIndexString = try container.decode(String.self, forKey: .checkpointIndex)
            let checkpointIndex = Int(checkpointIndexString)!

            let waitTimeString = try container.decode(String.self, forKey: .waitTime)
            let waitTime = Float(waitTimeString)!

            let createdDateTimeString =  try container.decode(String.self, forKey: .createdDateTime)

            let createdDateTime = WaitTime.formatter.date(from: createdDateTimeString)!

            self.init(checkpointIndex:checkpointIndex, waitTime:waitTime, createdDateTime:createdDateTime)
        }

        private enum CodingKeys: String, CodingKey {
            case checkpointIndex = "CheckpointIndex"
            case waitTime = "WaitTime"
            case createdDateTime = "Created_Datetime"
        }
    }
}