I fount this solution but I can't make it into swift code
This what I try
var pattern[2]:CGFloat; this
var dashed: CGPathRef = CGPathCreateCopyByDashingPath(CGPathCreateCopyByDashingPath(path, transform, phase, lengths, count);
var myShapeNode: SKShapeNode!;
var CGPathCreateCopyByDashingPath:CGPathRef;
This is how you can draw a dashed line in swift. You can change the parameters as you want.
let bezierPath = UIBezierPath()
let startPoint = CGPointMake(0, 250)
let endPoint = CGPointMake(450, 250)
bezierPath.moveToPoint(startPoint)
bezierPath.addLineToPoint(endPoint)
var pattern : [CGFloat] = [10.0, 10.0]
let dashed = CGPathCreateCopyByDashingPath (bezierPath.CGPath, nil, 0, pattern, 2)
var shapeNode = SKShapeNode(path: dashed)
shapeNode.position = CGPointMake(100, 100)
self.addChild(shapeNode)