Simple double jump code for Unity Engine

DoubleJump.cs

//FROM PROJECT ROROPE || REAL GAMES STUDIO
//************************************************
//realgamesss.weebly.com
//gamejolt.com/@Real_Game
//realgamesss.newgrounds.com/
//real-games.itch.io/
//youtube.com/channel/UC_Adg-mo-IPg6uLacuQCZCQ
//************************************************

using UnityEngine;

public class DoubleJump : MonoBehaviour
{
    Rigidbody2D rb;

    public float speed = 50;
    public float jumpForce = 20;

    public bool isGrounded;
    public bool isJumping;
    
    void Start()
    {
        rb = GetComponent<Rigidbody2D>();
    }

    
    void Update()
    {
        if (Input.GetKey(KeyCode.D))
        {
            rb.velocity = new Vector2(speed, rb.velocity.y);
        }
        else if (Input.GetKey(KeyCode.A))
        {
            rb.velocity = new Vector2(-speed, rb.velocity.y);
        }
        else
        {
            rb.velocity = new Vector2(0, rb.velocity.y);
        }

        if (Input.GetKeyDown(KeyCode.Space) && isGrounded == true)
        {
            rb.velocity = new Vector2(rb.velocity.x, jumpForce);
            isJumping = true;
        }
        else if (Input.GetKeyDown(KeyCode.Space) && isJumping == true)
        {
            rb.velocity = new Vector2(rb.velocity.x, jumpForce);
            isJumping = false;
        }
    }

    void OnCollisionEnter2D(Collision2D collision)
    {
        if (collision.gameObject.CompareTag("Ground"))
        {
            isGrounded = true;
        }
    }

    void OnCollisionExit2D(Collision2D collision)
    {
        isGrounded = false;
    }
}

It's worked, thanks!