iMac freezes after while loop - swift

Question

I'm creating a game in xcode. The winner will have a negative score or 0. Everything went well but now I want those negative points to be added to his/hers opponent. I used this code:
while (activePlayer.score < 0) {
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
self.activePlayer.score += 1
self.activePlayer.scoreLabel.text = String (self.activePlayer.score)
self.notActivePlayer.score += 1
self.notActivePlayer.scoreLabel.text = String (self.notActivePlayer.score)
}
}
When I now run the Simulator it freezes when it comes to this part. The worst thing is my whole iMac freezes. It's becoming so extremely slow I have to wait like 10 minutes to close the simulator and getting some speed back.
My simple conclusion is this code is wrong. But why?
I want to player to see the score change that's why the label text will be updated after every point added to the score.

Answer 1

Your while loop is a very bad idea there. What do you expect it to do? On first iteration you schedule an asnyc task, then the iteration is complete and the next task is scheduled, etc.
You will have a couple of thousand async task scheduled in the first split second the loop is running.
If you want to animate the change you should do it by scheduling the next task after the first finished. The following is a general way of doing that, I have not run it in Playground:
func schedule() {
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
self.activePlayer.score += 1
self.activePlayer.scoreLabel.text = String (self.activePlayer.score)
self.notActivePlayer.score += 1
self.notActivePlayer.scoreLabel.text = String (self.notActivePlayer.score)
if (activePlayer.score < 0) {
self.schedule()
}
}
}
As Whirlwind correctly pointed out using dispatch in sprite-kit makes you break out of the present game-loop. You can do the same thing via SKActions and repeatedly create new actions after one completed.