CodableInit.swift

protocol CodableInit {

  init(data: Data) throws

}

extension CodableInit where Self: Codable {
  
  init(data: Data) throws {

    let decoder = JSONDecoder()
    // I'm using snake case strategy, also Codable.
    // again you can use your own decoding lib/strategy

    decoder.keyDecodingStrategy = .convertFromSnakeCase

    self = try decoder.decode(Self.self, from: data)

  }

}