perform action every 3 time in each in for loop - swift

Question

I had a function for setting up a timer, how can I perform an action every 3 times in each(1,2,3 and 4 = 1 ,5 = 2, 6 = 3) still 6 or more in for loop?
func duration(interval:Double,rep:Int){
let queue = DispatchQueue.main
let timer = DispatchSource.makeTimerSource(queue: queue)
var num = 0
for i in 0...12{
if (i%3 == 0){
perform something
num ++
}else if (i%2 == 0){
perform something
num ++
}else{
perform something
num ++
}
if num == 12{
timer.cancel()
}
}
}```

Answer 1

The SwiftUI way to do this is a Timer publisher.
Example:
struct ContentView: View {
#State private var number = 0
#State private var multiple: Int?
private let startDate = Date()
private let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
var body: some View {
VStack {
Text("Number: \(number)")
Text("Multiple: \(multiple != nil ? String(multiple!) : "no")")
}
.onReceive(timer) { date in
let interval = Int(date.timeIntervalSince(startDate))
print(interval)
number = interval
if interval.isMultiple(of: 3) {
// multiple of 3
multiple = 3
} else if interval.isMultiple(of: 2) {
// multiple of 2 (careful - 6 will be ignored because it is already a multiple of 3)
multiple = 2
} else {
// neither multiple of 2 or 3
multiple = nil
}
if interval == 12 {
timer.upstream.connect().cancel()
}
}
}
}
Result: