how to move an object in 2D sense its position?

Hello, I'm creating a game with a two-dimensional craft similar to the arcade classic Asteroids mechanism. I was searching some forums, but found nothing on forward shift in position towards the front of the ship.

could someone help me? I need the script to be in javascript.

I already created the rotation of the sprite:

 var speed = 100.0;
  
 function Update ()
 {   
     if(Input.GetKey("left"))
     {
     transform.RotateAround(transform.forward,0.01);
     }
  
     if(Input.GetKey("right"))
     {
     transform.RotateAround(transform.forward,-0.01);
     }
  
     var z = Input.GetAxis("Vertical") * Time.deltaTime * speed; transform.Translate(0, 0, z);
 }