[Gsap.to() equals in pure js/css]

Thank you for the welcome and the reply @OSUblake

It's a bit disappointing though, no js/ css alternative for the gsap.to, but at least I got some valuable sources to learn. Thank you

[Gsap.to() equals in pure js/css]

Hello, I'm a new user in the world of GSAP. For one reason, I'd like to know for the gsap.to() equals in pure css/ javascript. I's rather to learn the basic properties that gsap.to() uses to animate it. This is an example from Chris Course in Youtube:

 

class Enemy {
    constructor(x,y,rad,color,velocity){
        this.x = x;
        this.y = y;
        this.rad =rad;
        this.color = color;
        this.velocity = velocity;
    }

    create() {
        c.beginPath();
        c.arc(this.x, this.y, this.rad, 0, Math.PI *2, false);
        c.fillStyle = this.color;
        c.fill();
    }

    update() {
        this.create();
        this.x += this.velocity.x;
        this.y += this.velocity.y;
    }
}

//When a bullet reach a big enemy 
gsap.to(Enemy, { rad: Enemy.rad -11 });
//...

Is there any pure css or javascript equal for the gsap.to() in the example? Thank you in advance