How to solve rendering a Heterogeneous collection when you are required to use a Homogeneous List of Objects in SwiftUI, In short use a Wrapper / Box around the content

ListOfAnimals.swift

//
//  ListOfAnimals.swift
//  AnimalList
//
//  Created by Paul Wood on 8/4/19.
//  Copyright © 2019 Paul Wood. All rights reserved.
//

import SwiftUI

protocol Animal {
  var displayName: String { get }
  var action: () -> () { get } // a closure that does some work
}

struct Dog: Animal {
  private var name: String
  var displayName: String {
    return "I'm a Good Dog named: \(name)"
  }
  var action: () -> () {
    get {
      return self.bark
    }
  }
  
  init(_ value: String) {
    self.name = value
  }
  
  func bark() {
    print("bark")
  }
}

struct Cat: Animal {
  var name: String
  var displayName: String {
    return "I'm the best Cat named: \(name)"
  }
  var action: () -> () {
    get {
      return self.meow
    }
  }
  
  init(_ value: String) {
    self.name = value
  }
  
  func meow() {
    print("meow")
  }
}

struct Bat {
  var name: String = "Dracula"
  func scaryNoises() {
    print("Muahahahahah am I really an Animal? No I'm Dracula")
  }
}

//: Wrapper around the specialized name types above
//: We know how this type will be used so now it conforms to Identifiable
//: instead of the models above
struct AnimalHolder: Animal, Identifiable {
  var id: UUID
  var displayName: String
  var action: () -> ()
  init<U>(nameable name: U) where U: Animal {
    self.displayName = name.displayName
    self.action = name.action
    self.id = UUID()
  }
  
  init(bat: Bat) {
    self.displayName = "I'm a bat"
    self.action = bat.scaryNoises
    self.id = UUID()
  }
}

let animals: [AnimalHolder] = [
  AnimalHolder(nameable: Dog("Alice")),
  AnimalHolder(nameable: Dog("Bob")),
  AnimalHolder(nameable: Cat("Clark")),
  AnimalHolder(nameable: Cat("Davis")),
  AnimalHolder(nameable: Dog("Elanore")),
  AnimalHolder(nameable: Dog("Frank")),
  AnimalHolder(nameable: Cat("Gonzalez")),
  AnimalHolder(nameable: Cat("Harris")),
  AnimalHolder(nameable: Cat("Harris")), //Can Duplicate
  AnimalHolder(nameable: Dog("Harris")), // Can go across types
  AnimalHolder(bat: Bat())
]

struct AnimalDetail: View {
  
  var animal: AnimalHolder
  
  var body: some View {
    VStack {
      Spacer()
      Text("Animal").font(.title)
      Text(animal.displayName).font(.body)
      Button(action: {
        print("play pressed")
        self.animal.action()
      }, label: {
        Image(systemName: "play")
        Text("Make My Noise")
      })
        .foregroundColor(Color.white)
        .padding()
        .background(Color.blue)
        .cornerRadius(5)
      Spacer()
    }
  }
}

struct ListOfAnimals: View {
  var body: some View {
    NavigationView {
      List(animals) { animal in
        NavigationLink(destination: AnimalDetail(animal: animal)) {
          HStack {
            Text(animal.displayName)
          }
        }
      }
    }
  }
}


#if DEBUG
struct ContentView_Previews: PreviewProvider {
  static var previews: some View {
    MultipleIdentifiableList()
  }
}
#endif