(Xcode Swift SpriteKit) How do I move a sprite in the direction it is facing - sprite-kit

Question

I have a sprite in the centre of the screen which can be rotated left or right which is determined by touching the left or right part of the screen.
What I would like to do is have the sprite continuously moving forwards but always in the direction it is facing. I know how to do basic movement with SKActions etc... but have no idea how I calculate the movement to be continuously in the direction that the sprite has rotated to?
Maths has never been my strong point so would very much appreciate some sample code to help me along.
var player = SKSpriteNode()
override func didMove(to view: SKView) {
player = SKSpriteNode(imageNamed: "4B.png")
player.setScale(0.3)
player.zPosition = 100
self.addChild(player)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first {
let position = touch.location(in: self)
if position.x < 0 {
let rotate = SKAction.repeatForever(SKAction.rotate(byAngle: CGFloat(M_PI), duration: 2))
player.run(rotate, withKey: "rotating")
} else {
let rotate = SKAction.repeatForever(SKAction.rotate(byAngle: CGFloat(-M_PI), duration: 2))
player.run(rotate, withKey: "rotating")
}
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
player.removeAction(forKey: "rotating")
}
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
}
}

Answer 1

You will need to use sin and cos. An SKAction may not be the best thing for you, so I would just do this in the update method for now till you find a better spot:
sprite.position = CGPoint(x:sprite.position.x + cos(sprite.zRotation) * 10,y:sprite.position.y + sin(sprite.zRotation) * 10)
Where 10 is the magnitude that you want the sprite to move (aka move 10 pixels)
This assumes that angle 0 means the sprite is looking right, angle 90 (PI/2) is looking up, angle 180 (PI) is looking left, and angle 270 (3PI/2) is looking down.