Cached sort

sort.swift

import SwiftUI

struct Counter: Identifiable, Equatable {
    let id = UUID()
    var count = 0
}

struct ContentView: View {
    @State var counters: [Counter] = [.init(), .init(), .init()]
    
    var body: some View {
        NavigationStack {
            HStack {
                SortedView(counters: $counters)
                SortedView(counters: $counters)
            }
        }
    }
}

struct SortedView: View {
    @Binding var counters: [Counter]
    @State var sortedCounters: [Binding<Counter>] = []
    @State var ascending = false
    
    var body: some View {
        List {
            Button(ascending ? "Ascending" : "Descending") {
                ascending.toggle()
            }
            ForEach(sortedCounters) { $c in
                Button("\(c.count, format: .number)") {
                    c.count += 1
                }
            }
        }
        .onChange(of: counters, initial: true) {
            withAnimation {
                sortedCounters = $counters.map(\.projectedValue)
                sort()
            }
            
        }
        .onChange(of: ascending) {
            withAnimation {
                sort()
            }
        }
    }
    
    func sort() {
        let sort = SortDescriptor(\Binding<Counter>.wrappedValue.count, order: ascending ? .forward : .reverse)
        sortedCounters.sort(using: sort)
    }
}