Delete all members from a Facebook group

delete-all-members.js

(async function (...protectedMembers) {
  const currentUserID = new URL('file://' + JSON.parse(document.getElementById("__eqmc").innerHTML).u).searchParams.get('__user');
  if (!protectedMembers || !Array.isArray(protectedMembers) || protectedMembers.length <= 0 || !protectedMembers.includes(currentUserID)) throw Error(`Add your ID (${currentUserID}) to protected members or you will delete yourself`)
  async function navigateAndRun() {
    try {
      const [, name, rest] = /^\/groups\/([\w\d.]+)(\/.+)?$/.exec(document.location.pathname);
      if (rest !== "/people/members") {
        alert("Navigating to correct page, rerun the script there");
        document.location.pathname = `/groups/${name}/people/members`;
      }
    }
    catch {
      alert("Please navigate to a group page");
    }
    await main();
  }
  const sleep = (ms, arg) => new Promise(res => setTimeout(res, ms, arg));
  /**
   * @param {DocumentFragment} element
   * @param {string} selector
   * @returns {Element}
   */
  function getExactlyOne(element, selector) {
    const result = getUpToOne(element, selector);
    if (!result) throw new Error(`Facebook has changed, there are no ${selector} on the ${element}, the script is outdated`);
    return result;
  }
  /**
   * @param {DocumentFragment} element
   * @param {string} selector
   * @returns {Element | undefined}
   */
  function getUpToOne(element, selector) {
    const result = element.querySelectorAll(selector);
    if (result.length > 1) {
      console.error("selector", selector, "on element", element, "resulted in multiple matches", ...result, result);
      throw new Error(`Facebook has changed, there is more than one ${selector} on the ${element}, the script is outdated`);
    };
    return result[0];
  }
  class TimeoutError extends Error { }
  /**
   * @param {DocumentFragment} element
   * @param {string} selector
   * @returns {Promise<Element>}
   */
  const waitFor = (element, selector, timeout = 8192) =>
    new Promise((resolve, reject) => {
      const start = Date.now();
      const attempt = () => {
        try {
          const elm = getUpToOne(element, selector);
          if (elm) resolve(elm)
          else if (Date.now() - start > timeout) {
            console.error("timed out waiting for", selector, "on", element);
            reject(new TimeoutError(`timed out waiting for ${selector} on ${element}`));
          }
          else requestIdleCallback(attempt);
        } catch (err) { reject(new Error(err)); }
      }
      attempt()
    })
  const USER_REGEX = /^\/groups\/(\d+)\/user\/(\d+)\//;
  const HELP_REGEX = /^\/help\//;
  const STORIES_REGEX = /^\/stories\//;
  async function main() {
    while (true) {
      const list = getExactlyOne(document, '[role=list]');
      const children = list.children;
      for (const item of children) {
        const [avatar, nameLink] = item.querySelectorAll('a[href]');
        const hrefs = [avatar, nameLink].map(x => new URL(x.href));
        const userIDs = hrefs.map(x => USER_REGEX.exec(x.pathname)?.[2]);
        const userID = userIDs[0] ?? userIDs[1];
        let fullName
        let button
        if (
          (userIDs[0] && userID === userIDs[1])
          || (!userIDs[0] && userIDs[1] && STORIES_REGEX.test(hrefs[0].pathname))
        ) {
          fullName = nameLink.textContent;
          button = getExactlyOne(item, '[role=button]');
        }
        else if (userID && HELP_REGEX.test(hrefs[1].pathname)) {
          // This is probably an "Unavailable" member. Attempting to ban them often fails.
          const buttons = item.querySelectorAll('[role=button]');
          if (buttons.length !== 2) throw new Error(`Facebook has changed, there is not exactly two [role=button]s on a unavailable member, the script is outdated`);
          fullName = buttons[0].textContent;
          button = buttons[1];
        } else {
          item.style.backgroundColor = 'red';
          console.error("Unknown type of member", item, "skipping");
          continue;
        }
        if (protectedMembers.includes(userID)) {
          continue;
        }
        console.info("Banning user", userID, fullName);
        const clickable = getExactlyOne(button, '[role=none]');
        clickable.click();
        const menu = await waitFor(document, '[class=""]>[role=menu]');
        const items = menu.querySelectorAll('[role=menuitem]');
        [...items].find(x => x.textContent.contains("Ban from group")).click();
        for (const dialog of document.querySelectorAll('[role=dialog]:not([aria-label]):has([role=button][aria-label="OK"])')) getExactlyOne(dialog, '[role=button][aria-label="OK"]').click()
        const dialog = await waitFor(document, '[role=dialog]:not([aria-label]):has([aria-checked]):has([aria-label="Confirm"]),[role=dialog]:not([aria-label]):has([aria-checked]):has([aria-label="Next"])');
        (await waitFor(dialog, '[aria-checked=false][aria-label="Delete recent activity"]')).click();
        const futureAccountsCheckbox = getUpToOne(dialog, '[aria-checked=false][aria-label^="Ban "][aria-label$="\'s future accounts"]');
        futureAccountsCheckbox?.click();
        await waitFor(dialog, '[aria-checked=true][aria-label="Delete recent activity"]');
        futureAccountsCheckbox && await waitFor(dialog, '[aria-checked=true][aria-label^="Ban "][aria-label$="\'s future accounts"]');
        getUpToOne(dialog, '[role=button][aria-label="Next"]:not([aria-disabled=true])')?.click(); // when this is a member of other groups you manage
        (await waitFor(dialog, '[role=button][aria-label="Confirm"]:not([aria-disabled=true])')).click();
        (async () => {
          const now = Date.now();
          while (!item.textContent.contains("Banned") && Date.now() - now < 2048) await sleep(256);
          item.remove();
          for (const dialog of document.querySelectorAll('[role=dialog]:not([aria-label]):has([role=button][aria-label="OK"])')) getExactlyOne(dialog, '[role=button][aria-label="OK"]').click()
        })()
      }
      await sleep(32);
    }
  }
  await navigateAndRun()
})('657792817', 'Your ID Here').catch(console.error)