Facebook Group Scraper with Tampermonkey and JavaScript

script.js

// ==UserScript==
// @name         Facebook Group Scraper
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       James Jeffery <[email protected]>
// @match        https://www.facebook.com/search/str/*/keywords_groups
// @grant        GM_setClipboard
// ==/UserScript==

let urls = null;

function MutationObserverCallback(mutations) {
    for(let mutation of mutations) {
        const groups = [].slice.call(mutation.target.querySelectorAll('a.lfloat[href*=groups]'));
        urls = groups.map(function(group) {
            return 'https://facebook.com' + group.getAttribute('href');
        });
    }
}

function injectButton() {
    const filterContainer = document.querySelector('div[data-testid=filters_container]');

    const button = document.createElement('button');
    button.innerText = 'Copy Groups';
    button.addEventListener('click', function(e) {
        GM_setClipboard(urls.join('\n'));
    });

    const filterSection = document.createElement('div');
    filterSection.setAttribute('data-testid', 'filters_section');

    const filterHeader = document.createElement('h4');
    filterHeader.innerText = 'COPY TO CLIPBOARD';

    filterSection.appendChild(filterHeader);
    filterSection.appendChild(button);
    filterContainer.appendChild(filterSection);

}

window.addEventListener('load', function() {
    injectButton();
    const targetNode = document.querySelector('#pagelet_loader_initial_browse_result > div > div');
    const config = { childList: true };
    const observer = new MutationObserver(MutationObserverCallback);
    observer.observe(targetNode, config);
});