This PropertyWrapper allow a property to not be encoded with Codable without needed to create a custom CodingKeys.

NotCodable.swift

import Foundation

/// This allow a property to no be encoded
@propertyWrapper 
public struct NotCodable<Boxed> {
  private var value: Boxed?
  
  public init(wrappedValue: Boxed?) {
    self.value = wrappedValue
  }
  
  public var wrappedValue: Boxed? {
    get { value }
    set { self.value = newValue }
  }
}

extension NotCodable: Decodable where Boxed: Decodable {
  public init(from decoder: Decoder) throws {
    self.value = nil
  }
}

extension NotCodable: Encodable where Boxed: Encodable {
  public func encode(to encoder: Encoder) throws {
    /// Do not encode
  }
}

extension NotCodable: Equatable where Boxed: Equatable {
  public static func == (lhs: NotCodable<Boxed>, rhs: NotCodable<Boxed>) -> Bool {
    lhs.wrappedValue == rhs.wrappedValue
  }
}

extension NotCodable: Hashable where Boxed: Hashable {
  public func hash(into hasher: inout Hasher) {
    hasher.combine(wrappedValue)
  }
}