Adds puzz.link buttons to the database

puzzlink.js

// ==UserScript==
// @name         puzz.link Add link
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Adds puzz.link buttons to the database
// @author       RSP
// @match        https://puzz.link/db*
// @icon         https://puzz.link/favicon-32x32.png
// @grant        none
// @run-at       document-idle
// ==/UserScript==

/* script adapted from Lavaloid's modification of Eric Fox's original script */

(function() {
    'use strict';

    let lk = [];
    let last = '';

    setInterval(function() {
        let now = document.getElementsByTagName('img')[0] ?? {};
        if (now.src !== last) lk = add_puzzlinks();
        last = now;
    }, 1000);

    //create openall button
    let openall = document.createElement('button');
    openall.addEventListener('click', () => {
        lk = add_puzzlinks();
        lk.forEach((l) => window.open(l));
    });
    openall.innerText = 'open all';
    document.getElementsByClassName('paging')[0].appendChild(openall);
})();

function add_puzzlinks() {
    let links = [];
    [...document.getElementsByClassName('pzvpuzzle')].forEach((pz) => {
        let link = pz.getElementsByTagName("img")[0].src.replace("v?thumb&","?");
        if (!pz.getElementsByClassName('plink').length) {
                pz.insertAdjacentHTML('beforeend', '<div class="plink"><a target="_blank" href="' + link + '">[puzz.link]</a></div>');
                pz.getElementsByTagName('a')[0].href = link;
            }
        links.push(link);
    });
    return links;
}