How to generated unique id in ForEach with [Int] - swiftui

Question

I am using a ForEach to construct a number of views based on an array of integers.
This array of integers can contain duplicate values. In addition, since an Int is not Identifiable I have to use a key path. When using \.self however, I get bad results (the colors of the rectangle are not correctly set) due to the duplicate values.
What would be the easiest way to create unique identifiers or keypaths to fix this?
#ViewBuilder
func stackFor(bar: Bar, scale: CGFloat) -> some View {
//sample data
let values = [4,4,5,6]
var index = 0
//create stack of view
//==> since an Int is not identifiable I have to use keypath
// however \.self is not unique as we have 2x the value 4 in the values
// this leads bad results because there are duplica ids
ForEach(values, id: \.self) { value in
Rectangle()
.fill(colorForStackedBar(index: index))
.frame(height: heightFor(value: value, scale: scale) )
Rectangle()
.fill(Color.clear)
.frame(height: 1 )
//the let _ = ... is just a "hack" for being able to update the index in #ViewBuilder
let _ = index = index + 1
}
}
func colorForStackedBar(index: Int) -> Color {
return barColors[safeIndex: index] ?? .red
}
func heightFor(value: Int, scale: CGFloat) -> CGFloat {
let height = CGFloat(value) * scale
//at least 1 point so to see __ on the bottom for zero (or missing) entries (as used on other apps)
return max(1, height)
}

Answer 1

I found a solution by wrapping the Int into an Unique:Identifiable struct. However, I don't really think this is the most beautiful solution. There most be a better way?
struct Unique: Identifiable {
let value: Int
let id = UUID()
}
#ViewBuilder
func stackFor(bar: Bar, scale: CGFloat) -> some View {
//sample data
let values = [4,4,5,6]
var index = 0
//generate a uuid for the whole array of values
let uniques = values.map({Unique(value: $0)})
ForEach(uniques) { unique in
Rectangle()
.fill(colorForStackedBar(index: index))
.frame(height: heightFor(value: unique.value, scale: scale) )
Rectangle()
.fill(Color.clear)
.frame(height: 1 )
//the let _ = ... is just a "hack" for being able to update the index in #ViewBuilder
let _ = index = index + 1
}
}

Answer 2

Here array has duplicates but also works!
import SwiftUI
struct ContentView: View {
var body: some View {
stackFor(scale: 1.0)
}
}
func stackFor(scale: CGFloat) -> some View {
let values: [Int] = [4 ,4 ,4 ,4 ,4 ,20, 20, 20, 50, 50, 50]
return VStack(spacing: 0.0) {
ForEach(values, id: \.self) { value in
Rectangle()
.fill(colorForStackedBar(index: value))
.frame(height: heightFor(value: value, scale: scale) )
Rectangle()
.frame(height: 5.0)
}
}
}
func colorForStackedBar(index: Int) -> Color {
return Color.red
}
func heightFor(value: Int, scale: CGFloat) -> CGFloat {
return max(1.0, CGFloat(value)*scale)
}

Answer 3

You can make the Unique struct conform to ExpressibleByIntegerLiteral:
struct Unique: Identifiable, ExpressibleByIntegerLiteral {
let value: Int
let id = UUID()
init(integerLiteral value: Int) {
self.value = value
}
}
which makes it easier to create an array of Unique:
let uniques: [Unique] = [4,4,5,6]