ForEach with dynamic vs. static range - swiftui

Question

I've been struggling with an-otherwise simple issue I'm sure. I can't seem to find the proper way to use ForEach with a dynamic range.
I have the following simple demo showing my issue. tapGesture on anySquare will update a #State variable array to make square 1 disappear / appear. Works like a charm on the right side but doesn't within a ForEach.
#State var visibilityArray = [true,true]
var body: some View {
ZStack {
Color.white
HStack {
VStack{
Text("Dynamic")
ForEach(visibilityArray.indices) { i in
if self.visibilityArray[i] {
Rectangle()
.frame(width: 100, height: 100)
.overlay(Text(String(i)).foregroundColor(Color.white))
.onTapGesture {
withAnimation(Animation.spring()) {
self.visibilityArray[1].toggle()
}
}
}
}
}
VStack{
Text("Static")
if self.visibilityArray[0] {
Rectangle()
.frame(width: 100, height: 100)
.overlay(Text("0").foregroundColor(Color.white))
.onTapGesture {
withAnimation(Animation.spring()) {
self.visibilityArray[1].toggle()
}
}
}
if self.visibilityArray[1] {
Rectangle()
.frame(width: 100, height: 100)
.overlay(Text("1").foregroundColor(Color.white))
.onTapGesture {
withAnimation(Animation.spring()) {
self.visibilityArray[1].toggle()
}
}
}
}
}
}
}

Answer 1

Xcode error occurring when you try to modify your array used in a ForEach loop (eg. by replacing it with another array) provides a good guidance:
ForEach(_:content:) should only be used for constant data.
Instead conform data to Identifiable or use ForEach(_:id:content:)
and provide an explicit id!
You can use this code to make your ForEach work:
ForEach(visibilityArray, id: \.self) {
This also means that for every item in the loop you have to return some View. I suggest passing the filtered array (only with items you want to display/use) as an input to the ForEach loop.