Contrived example illustrating problems with singleValueContainer on Encoder, and maybe Character not being Codable.

Suit+Codable.swift

// Contrived example illustrating problems with singleValueContainer on Encoder, and maybe Character not being Codable.

import XCTest

enum Suit: Character {
	case diamonds = "♦"
	case clubs = "♣"
	case hearts = "♥"
	case spades = "♠"
}

extension Suit: Codable { // Character isn't Codable
	
	public func encode(to encoder: Encoder) throws {
		var container = encoder.singleValueContainer()
		try container.encode(String(self.rawValue)) // Encode as String
	}
	
	public init(from decoder: Decoder) throws {
		let container = try decoder.singleValueContainer()
		let character = try container.decode(String.self).first!
		self.init(rawValue: character)!
	}
}

let diamonds = Suit.diamonds

let encoder = JSONEncoder()
let encoded = try encoder.encode(diamonds)

// Playground execution terminated: An error was thrown and was not caught:
// ▿ EncodingError
//   ▿ invalidValue : 2 elements
//     - .0 : __lldb_expr_27.Suit.diamonds
//     ▿ .1 : Context
//       - codingPath : 0 elements
//       - debugDescription : "Top-level Suit encoded as string JSON fragment."
//       - underlyingError : nil

let decoder = JSONDecoder()
let decoded = try decoder.decode(Suit.self, from: encoded)

XCTAssertEqual(decoded, diamonds)

What’s the recommended way of working with singleValueContainer without wrapping in struct or Array, or using keying etc? See thread on Twitter.