[html] Scrolling to an Anchor using Transition/CSS3

I implemented the answer suggested by @user18490 but ran into two problems:

• First bouncing when user clicks on several tabs/links multiple times in short succession
• Second, the undefined error mentioned by @krivar

I developed the following class to get around the mentioned problems, and it works fine:

export class SScroll{
    constructor(){
        this.delay=501      //ms
        this.duration=500   //ms
        this.lastClick=0
    }

    lastClick
    delay
    duration

    scrollTo=(destID)=>{
        /* To prevent "bounce" */
        /* https://stackoverflow.com/a/28610565/3405291 */
        if(this.lastClick>=(Date.now()-this.delay)){return}
        this.lastClick=Date.now()

        const dest=document.getElementById(destID)
        const to=dest.offsetTop
        if(document.body.scrollTop==to){return}
        const diff=to-document.body.scrollTop
        const scrollStep=Math.PI / (this.duration/10)
        let count=0
        let currPos
        const start=window.pageYOffset
        const scrollInterval=setInterval(()=>{
            if(document.body.scrollTop!=to){
                count++
                currPos=start+diff*(.5-.5*Math.cos(count*scrollStep))
                document.body.scrollTop=currPos
            }else{clearInterval(scrollInterval)}
        },10)
    }
}

UPDATE

There is a problem with Firefox as mentioned here. Therefore, to make it work on Firefox, I implemented the following code. It works fine on Chromium-based browsers and also Firefox.

export class SScroll{
    constructor(){
        this.delay=501      //ms
        this.duration=500   //ms
        this.lastClick=0
    }
    lastClick
    delay
    duration
    scrollTo=(destID)=>{
        /* To prevent "bounce" */
        /* https://stackoverflow.com/a/28610565/3405291 */
        if(this.lastClick>=(Date.now()-this.delay)){return}

        this.lastClick=Date.now()
        const dest=document.getElementById(destID)
        const to=dest.offsetTop
        if((document.body.scrollTop || document.documentElement.scrollTop || 0)==to){return}

        const diff=to-(document.body.scrollTop || document.documentElement.scrollTop || 0)
        const scrollStep=Math.PI / (this.duration/10)
        let count=0
        let currPos
        const start=window.pageYOffset
        const scrollInterval=setInterval(()=>{
            if((document.body.scrollTop || document.documentElement.scrollTop || 0)!=to){
                count++
                currPos=start+diff*(.5-.5*Math.cos(count*scrollStep))
                /* https://stackoverflow.com/q/28633221/3405291 */
                /* To support both Chromium-based and Firefox */
                document.body.scrollTop=currPos
                document.documentElement.scrollTop=currPos
            }else{clearInterval(scrollInterval)}
        },10)
    }
}