Autotrader.co.uk userscript hiding certain cars

autotrader-userscript.js

// ==UserScript==
// @name         New Userscript
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        https://www.autotrader.co.uk/car-search*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=autotrader.co.uk
// @grant        none
// ==/UserScript==

const storage = getStorage();
(function() {
    'use strict';

    console.log("storage contents", storage);


    const mainDiv = document.getElementById("root");

    let observer = new MutationObserver(callback);
    observer.observe(mainDiv, {
        childList: true,
        attributes: false,
        characterData: true,
        subtree: true
    });
})();

function getStorage(){
    const item = localStorage.getItem("hidden-adverts");
    if (!item) {
        return {};
    }
    return JSON.parse(item)
}
function callback(xx){
    //console.log("callback")
    //delete ads
    const nodes = getElementsByXpath("//li[./section/span[text()='Ad']]");
    for (let i=0; i<nodes.snapshotLength; i++) {
        let section = nodes.snapshotItem(i);
        section.style.display = "none";
    }
    appendDelete();
}
function appendDelete(){
    let nodes = getElementsByXpath("//li/section");

    for (let i=0; i<nodes.snapshotLength; i++) {
        let section = nodes.snapshotItem(i);
        const sectionID = section.getAttribute("id");
        //console.log(storage);

        //debugger;
       if (storage[sectionID]){
            setElementAsHidden(section);
            continue;
        }
        if (section.querySelector("img.delete")){
            console.log("got image already");
            continue;
        }
        section.style.color = "#f1c40f";
        //        console.log(section);

        const deleteButton = document.createElement("img");
        deleteButton.classList.add("delete");
        deleteButton.setAttribute("src", "https://cdn-icons-png.flaticon.com/24/1828/1828851.png");
        deleteButton.style.position = "absolute";
        deleteButton.style.top = "5px";
        deleteButton.style.right = "5px";
        deleteButton.style.zIndex = 1000;
        deleteButton.setAttribute("data-id",sectionID);
        deleteButton.addEventListener("click", hideAdvert);


        section.appendChild(deleteButton);
        //console.log("Added image", deleteButton);
    }

    /*

    while (section){
        const script = document.createElement("img");
        script.setAttribute("src", "https://cdn-icons-png.flaticon.com/24/1828/1828851.png");
        section.appendChild(script);
        console.log(section);
        section = nodes.iterateNext();
    }*/
    console.log(nodes);
}
function hideAdvert(obj){
    const target = obj.target;
    const id = obj.target.getAttribute("data-id");
    var section = document.getElementById(id);
    setElementAsHidden(section);
    storage[id] = true;
    localStorage.setItem("hidden-adverts", JSON.stringify(storage));
    console.log(storage);
}
function setElementAsHidden(el){
    el.classList.add("hidden-advert");
    el.style.display = "none";
}
function getElementByXpath(path) {
    return document.evaluate(path, document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;
}
function getElementsByXpath(path) {
    return document.evaluate(path, document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
}