Ok, the reason is in documentation for used ForEach constructor (as you see range is constant, so ForEach grabs initial range and holds it):
/// Creates an instance that computes views on demand over a *constant*
/// range.
///
/// This instance only reads the initial value of `data` and so it does not
/// need to identify views across updates.
///
/// To compute views on demand over a dynamic range use
/// `ForEach(_:id:content:)`.
public init(_ data: Range<Int>, @ViewBuilder content: @escaping (Int) -> Content)
So the solution would be to provide dynamic container. Below you can find a demo of possible approach.
Full module code
import SwiftUI
struct DummyView: View {
@State var animals: [String] = ["🐶", "🐱"]
var body: some View {
VStack {
HStack {
EditButton()
Button(action: { self.animals.append("Animal \(self.animals.count + 1)") }, label: {Text("Add")})
}
List {
ForEach(animals, id: \.self) { item in
EditorView(container: self.$animals, index: self.animals.firstIndex(of: item)!, text: item)
}
.onDelete { indexSet in
self.animals.remove(atOffsets: indexSet) // Delete "🐶" from animals
}
}
}
}
}
struct EditorView : View {
var container: Binding<[String]>
var index: Int
@State var text: String
var body: some View {
TextField("", text: self.$text, onCommit: {
self.container.wrappedValue[self.index] = self.text
})
}
}