Expand titles and show playlist popup if video is on some playlist

Youtube Tampermonkey.js

// ==UserScript==
// @name         Youtube script
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        https://www.youtube.com/*
// @run-at       document-end
// @grant        none
// ==/UserScript==

(async function() {
    expandTitles();

    //wait till
    var buttonIndex = await waitTillSaveOrZapiszAppearAndReturnButtonIndex()

    click('style-scope ytd-button-renderer', buttonIndex)

    //wait till:
    await waitTillPopupAppear()

    var checkedAmount = document.getElementsByClassName('checked').length
    console.log("Checked amount:" + checkedAmount);

    if (checkedAmount == 0) {
        click('style-scope ytd-add-to-playlist-renderer', 3)
    }
})();

function expandTitles() {
    var elements = document.querySelectorAll('#video-title.yt-simple-endpoint.style-scope.ytd-grid-video-renderer');

    elements.forEach(element => {
        element.style.maxHeight = '7em';
        element.style.webkitLineClamp = '7'
    })
}

async function waitTillSaveOrZapiszAppearAndReturnButtonIndex() {
    var wasExceptionThrown;
    do {
        console.log("12346")
        wasExceptionThrown = false;
        try {
            var saveButton = document.getElementsByClassName('style-scope ytd-button-renderer')

            if (saveButton[8].innerText === 'ZAPISZ') {
                return 8;
            } else if (saveButton[10].innerText === 'SAVE') {
                return 10;
            }
        } catch (e) {
            wasExceptionThrown = true
            await sleep(100);
        }
    } while (wasExceptionThrown);
}

function click(className, elementIndex) {
    console.log("123")
    var evt = document.createEvent("MouseEvents");
    evt.initMouseEvent("click", true, true, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
    document.getElementsByClassName(className)[elementIndex].dispatchEvent(evt);
    console.log("234")
}


function waitTillPopupAppear() {
    var wasExceptionThrown;
    
    console.log("1234")
    wasExceptionThrown = false;
    try {
        var hasPopupAppeared = document.getElementsByClassName('checkbox-height style-scope ytd-playlist-add-to-option-renderer')[0].innerText === 'Watch later'
    } catch (e) {
        wasExceptionThrown = true
        setTimeout(function () { waitTillPopupAppear()}
                 ,100);
        sleep(100)
    }
}

function sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}