cached sort 2

sort2.swift

import SwiftUI

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

struct SortedCounters {
    var _counters:  [Binding<Counter>] = []
    var counters: [Binding<Counter>] {
        get {
            _counters
        }
        set {
            _counters = newValue
            sort()
        }
    }
    
    var ascending = false {
        didSet {
            sort()
        }
    }
    
    mutating func sort() {
        let sort = SortDescriptor(\Binding<Counter>.wrappedValue.count, order: ascending ? .forward : .reverse)
        _counters.sort(using: sort)
    }
    
}

struct ContentView2: View {
    @State var counters: [Counter] = [.init(), .init(), .init()]
    @State var sortedCounters1 = SortedCounters()
    @State var sortedCounters2 = SortedCounters()
    @State var callBody = 0
    
    var body: some View {
        NavigationStack {
            Button("callBody \(callBody)") {
                callBody += 1
            }
            HStack {
                CounterView(x: callBody, sortedCounters: $sortedCounters1)
                CounterView(x: callBody, sortedCounters: $sortedCounters2)
            }
        }
        .onChange(of: counters, initial: true) {
            let x = $counters.map(\.projectedValue)
            sortedCounters1.counters = x
            sortedCounters2.counters = x
        }
    }
}



struct CounterView: View {
    let x: Int
    
    @Binding var sortedCounters: SortedCounters

    var body: some View {
        let _ = print(Self._printChanges())
        List {
            Button(sortedCounters.ascending ? "Ascending" : "Descending") {
                withAnimation {
                    sortedCounters.ascending.toggle()
                }
            }
            ForEach(sortedCounters.counters) { $c in
                Button("\(c.count, format: .number)") {
                    withAnimation {
                        c.count += 1
                    }
                }
            }
        }
    }
}