How to detect swipe direction?

[Roger Eller]

I want a different action to occur based on the direction the user swipes a
control.  For example:

   on swipeLeft
        set the backgroundColor of me to red
   end swipeLeft

   on swipeRight
        set the backgroundColor of me to green
   end swipeRight

Is there a one liner on mobile that can give me the direction, or
true/false, or l/r/u/d?

~Roger