SwiftUI view that will either ForEach over data or display given view if empty.

ForEachOrEmpty.swift

import SwiftUI



struct ForEachOrEmpty<Data, ID, ForEachContent, EmptyContent>: View where Data: RandomAccessCollection, ID: Hashable, ForEachContent: View, EmptyContent: View {
  let data: Data
  let forEachBuilder: (Data.Element) -> ForEachContent
  let emptyBuilder: () -> EmptyContent
  let identityKeyPath: KeyPath<Data.Element, ID>
  
  init(_ data: Data, id: KeyPath<Data.Element, ID>, @ViewBuilder each: @escaping (Data.Element)->ForEachContent, @ViewBuilder empty: @escaping () -> EmptyContent) {
    self.data = data
    identityKeyPath = id
    forEachBuilder = each
    emptyBuilder = empty
  }
  
  
  var body: some View {
    if data.isEmpty {
      return AnyView(emptyBuilder())
    } else {
      return AnyView(ForEach(data, id: identityKeyPath, content: forEachBuilder))
    }
  }
}



extension ForEachOrEmpty where ID == Data.Element.ID, Data.Element: Identifiable {
  init(_ data: Data, @ViewBuilder each: @escaping (Data.Element)->ForEachContent, @ViewBuilder empty: @escaping () -> EmptyContent) {
    self.init(data, id: \.id , each: each, empty: empty)
  }
}




struct ForEachOrEmpty_Previews: PreviewProvider {
  static let someNumbers = [1,2,3]
  static let noNumbers: [Int] = []
  
  
  struct IDString: Identifiable {
    let value: String
    var id: String { value }
    init(_ value: String) { self.value = value }
  }
  static let someLetters = [IDString("a"), IDString("b"), IDString("c")]
  static let noLetters: [IDString] = []
  
  
  static var previews: some View {
    Group {
      VStack {
        Divider()
        ForEachOrEmpty(someNumbers, id: \.self, each: { number in
          VStack {
            Text("number \(number)")
            Divider()
          }
        }, empty: {
          VStack {
            Text("None")
            Divider()
          }
        })
      }
      
      VStack {
        Divider()
        ForEachOrEmpty(noNumbers, id: \.self, each: { number in
          VStack {
            Text("number \(number)")
            Divider()
          }
        }, empty: {
          VStack {
            Text("None")
            Divider()
          }
        })
      }
      
      VStack {
        Divider()
        ForEachOrEmpty(someLetters, each: { letter in
          VStack {
            Text(letter.value)
            Divider()
          }
        }, empty: {
          VStack {
            Text("None")
            Divider()
          }
        })
      }
      
      VStack {
        Divider()
        ForEachOrEmpty(noLetters, each: { letter in
          VStack {
            Text(letter.value)
            Divider()
          }
        }, empty: {
          VStack {
            Text("None")
            Divider()
          }
        })
      }
      
    }.previewLayout(.sizeThatFits)
  }
}