How to flip 2D character to face direction of movement

 using System.Collections;
 using UnityEngine;
 
 public class PlayerController : MonoBehaviour
 {
     public bool dead = false;
     public float speed;
     private Rigidbody2D rb2d;
     public GameObject[] health;
     public GameObject Hazard;
     public GameObject HealthPickup;
     private bool facingRight;
     private void Start()
     {
         facingRight = true;
         rb2d = GetComponent<Rigidbody2D>();
     }
     void FixedUpdate()
     {
         if (Input.GetKey("w") || Input.GetKey("a") || Input.GetKey("s") || Input.GetKey("d"))
         {//find controller inputs
             float moveHorizontal = Input.GetAxisRaw("Horizontal");
             float moveVertical = Input.GetAxisRaw("Vertical");
 
             transform.Translate(moveHorizontal * speed * Time.deltaTime, moveVertical * speed * Time.deltaTime, 0);
 
         }
         else
         {
             float moveHorizontal = Input.GetAxisRaw("JoystickHorizontal");
             float moveVertical = Input.GetAxisRaw("JoystickVertical");
 
             transform.Translate(moveHorizontal * speed * Time.deltaTime, moveVertical * speed * Time.deltaTime, 0);
             //wowie here im trying
         }
 
     }
     private void Flip(float moveHorizontal)
     {
         if (moveHorizontal > 0 && !facingRight || moveHorizontal < 0 && facingRight)
         {
             facingRight = !facingRight;
             Vector3 theScale = transform.localScale;
             theScale.x *= -1;
             transform.localScale = theScale;
         }
     }
 
 
 
     public void OnTriggerEnter(Collider other)
     {
         if (other.CompareTag("Hazard"))
         {
             SendMessage("TakeDamage", 1);
             Destroy(other.gameObject);
         }
 
         if (other.CompareTag("HealthPickup"))
         {
             SendMessage("Heal");
             Destroy(other.gameObject);
         }
     }
 }
 
 I'm sorry if I'm making a stupid mistake somewhere, I am very new to this. Any help would be appreciated. I'm trying to make my 2D character flip by making the x Scale -1 when the character switches direction.