All I'm wanting is an update method with a time delta from the previous frame, but every example I'm finding is either for Swift on iOS, or with Objective-C for OSX, or uses NSTimer which is not recommended because it doesn't sync with the display refresh.
Does SpriteKit on OSX provide a simple way to just get an update method once per frame in pure swift code? A way to do it without SpriteKit would be even better.