Hammerspoon - undo/redo on mouse left/right on keypress

init.lua

hs.hotkey.bind({"cmd", "ctrl", "alt", "shift"}, "f1",
  -- next function is called on hotkey press
  function()
    startPoint = hs.mouse.absolutePosition()
  end,
  -- this is called on hotkey release
  function() end,
  -- this is called while the key remains pressed 
  function()
    local point = hs.mouse.absolutePosition()
    if (startPoint.x ~= point.x) then
      if (startPoint.x > point.x) then
        -- moving left / undo
        hs.eventtap.keyStroke({"cmd"}, "z", true)
      else
        print("r")
        -- moving right / redo
        hs.eventtap.keyStroke({"cmd", "shift"}, "z", true)
      end
      startPoint = point
    end
  end
)