gsap slerpquaternion

[Dave-Patsy]

Hi, I am following this video https://www.youtube.com/watch?v=GeNjyb8UBKM&t=612s Teleportation with three.js transition #15 by Yuri Artiukh. He is coding in vanilla JS and is using gsap to do a transition. My code works, but I am not sure on why it is working.

I don't really understand this declaration let l = {p:0}.
I am not sure why it is working in gsap.to(l,{.....}
could someone explane?

this Yuri's code that turns a globe when a link element is clicked

points.forEach(p=>{
        let animatedQuaternion = new Quaternion()

        listEle.addEventListener('click',()=>{
            let o = {p:0} // I haven't seen this before. seems to declare an object
            let currentQuaternion = new Quaternion()
            currentQuaternion.copy(this.group.quaternion)
            gsap.to(o,{
                p:1,
                duration:1
                onUpdate: () =>{
                    animatedQuaternion.slerpQuaternions(currentQuaternion, calculatedCoords, o.p)
                    this.group.quaternion.copy(animatedQuaternion)
                }
           })  
}

This is my code. I am not using a listener right now. I am just changing the quaternion every 4 seconds.

    useFrame(({clock})=>{
        const a = clock.getElapsedTime()
        // const b = clock.getDelta()
        let temptime = Math.floor((a/4)% coordinates.length)

        let animatedQuaternion = new Quaternion()
        let currectQuaternion = new Quaternion()
        
        let l = {p:0}

        switch (temptime) {
            case 0:
                
                currectQuaternion.copy(groupRef.current.quaternion)
                gsap.to(l,{
                    p:1,
                    duration: 1,
                    onUpdate:()=>{
                        animatedQuaternion.slerpQuaternions(currectQuaternion,quaternion[0],l.p)
                        groupRef.current.quaternion.copy(animatedQuaternion)
                    }
                })
               
                break;
            case 1:
                
                currectQuaternion.copy(groupRef.current.quaternion)
                gsap.to(l,{
                    p:1,
                    duration: 1,
                    onUpdate:()=>{
                        animatedQuaternion.slerpQuaternions(currectQuaternion,quaternion[1],l.p)
                        groupRef.current.quaternion.copy(animatedQuaternion)
                    }
                })
                break;
            default:
                break;
        }

    })```