Scroll to index video on youtube playlist page

Youtube Watch Later Scroller.js

function scrollTillIndexNumber (indexToScroll) {

    window.scrollTo(0,document.querySelector("div.style-scope ytd-section-list-renderer").scrollHeight);

    var lastElementIndex = document.getElementsByTagName("yt-formatted-string").length;

    var currentLastIndex = (lastElementIndex - 8)/2;

    if (currentLastIndex < indexToScroll) {

           setTimeout(function () { scrollTillIndexNumber(indexToScroll)}
                     ,400);
           return;
   };
};

var videosElement = document.getElementsByClassName('ytd-playlist-sidebar-primary-info-renderer')[4].textContent.replace(' videos','');
var amountOfVideos = parseInt(videosElement)

scrollTillIndexNumber(amountOfVideos);