Codable+RawRepresentable.swift

// Allows us to persist any Codable with @AppStorage and @SceneStorage (via a JSON String).

public protocol RawCodable {
    static var emptyJSON: String { get }
}

public extension RawCodable where Self: Codable {
    init?(rawValue: String) {
        guard let data = rawValue.data(using: .utf8),
              let value = (try? JSONDecoder().decode(Self.self, from: data)) else { return nil }
        self = value
    }

    var rawValue: String {
        let data = (try? JSONEncoder().encode(self)) ?? Data()
        return String(data: data, encoding: .utf8) ?? Self.emptyJSON
    }
}

extension Array: RawCodable, RawRepresentable where Element: Codable {
    public static var emptyJSON: String { "[]" }
}

extension Dictionary: RawCodable, RawRepresentable where Key == String, Value: Codable {
    public static var emptyJSON: String { "{}" }
}