JavaScriptで横揺れ

yokoyure.coffee

count = 0
degree = 0
radian = 0
speed = 25
radius = 5
beforeLeft = @targetEnemy.css('left')
# centerX = parseInt(@targetEnemy.css('left'), 10) /2
x = (if beforeLeft is 'auto' then 0 else parseInt(beforeLeft, 10)) 
timer = setInterval(=>
  if count <= 100
		degree += speed
		# degreeは0～360
		degree = (degree % 360 + 360) % 360
		radian = degree * Math.PI / 180

		@targetEnemy.css
			left: x + (Math.cos(radian) * radius) + 'px'

		count += 1
	else
		clearInterval timer if count > 100
, 1)