Safely decode and encode enums in Swift

OptionalCodableEnum.swift

public struct OptionalCodableEnum<T>: Codable where T: RawRepresentable, T.RawValue: Codable {
    public let value: T?

    public init(value: T) {
        self.value = value
    }

    public init(from decoder: Decoder) throws {
        value = T(rawValue: try decoder.singleValueContainer().decode(T.RawValue.self))
    }

    public func encode(to encoder: Encoder) throws {
        var container = encoder.singleValueContainer()
        try container.encode(value?.rawValue)
    }
}