Wait until function is completed - swift

Question

I have to function for adding two sprites and moving, called Space1 and Space2. I need to make Space1 move Right to Left, after Space 1 is finished the moving. Then, Space2 will move Left to Right.
I can make them move by 2 functions Move1() and Move2(); but they started the same time.
How can I make the Space2 wait until the function Move1 of Space1 is completed and then Space2 start moving?
This is my code
// Create sprite
let space1 = SKSpriteNode(imageNamed: "Spaceship")
space1.position = CGPoint(x: 0, y: frame.height/2)
space1.xScale = 0.3;
space1.yScale = 0.3;
space1.name = "space1";
self.addChild(space1);
let space2 = SKSpriteNode(imageNamed: "Spaceship")
space2.position = CGPoint(x: frame.width, y:0)
space2.xScale = 0.3;
space2.yScale = 0.3;
space2.name = "space2";
self.addChild(space2);
let actualDuration = random(min: CGFloat(1), max: CGFloat(3))
// Create the actions
let actionMove1 = SKAction.moveTo(CGPoint(x: frame.width, y: frame.height/2), duration: NSTimeInterval(actualDuration))
let actionMove2 = SKAction.moveTo(CGPoint(x: 0, y: 0), duration: NSTimeInterval(actualDuration))
self.runAction(SKAction.sequence([SKAction.runAction(actionMove1, onChildWithName: "space1"),SKAction.runAction(actionMove2, onChildWithName: "space2")]))

Answer 1

You can use the completion handler of runAction function to get what you need. Start the next SKAction inside the completion handler of the first runAction function.
space1.runAction(actionMove1, completion: { () -> Void in
space2.runAction(actionMove2)
})

Answer 2

SpriteKit provides something called SKAction.sequence. You can give it an array of actions which will be started after the one before has finished:
func startAction(){
var space1 = SKSpriteNode()
var space2 = SKSpriteNode()
var move1 = SKAction()
var move2 = SKAction()
space1.name = "space1"
space2.name = "space2"
self.runAction(SKAction.sequence([SKAction.runAction(move1, onChildWithName: "space1"), SKAction.runAction(move2, onChildWithName: "space2")]))
}
As you see here, I add names to the SKSpriteNodes. That's important because as you can see in the sequence, you have to specify, on which node the action is getting called.
Also important to say is, that if you use sub-sequences, you need to work with SKAction.waitForDuration(sec: NSTimeInterval). For example:
self.runAction(SKAction.sequence([SKAction.runAction(move1, onChildWithName: "space1"), SKAction.waitForDuration(move1.duration), SKAction.runAction(move2, onChildWithName: "space2")]))}