Delete everyone from your Facebook group! Thanks for the dark UX, FB

FBGroupMemberRemover.js

class FBGroupMemberRemover {
  constructor() {
    this.adminText = 'Admin';
    this.removeMemberModalHeadingText = 'Remove Member';

    this.memberElementSelector = '[data-name="GroupProfileGridItem"]';
    this.memberContextMenuSelector = 'button[aria-label="Member Settings"]';
    this.removeMemberButtonSelector = 'a[data-testid="leave_group"]'

    this.removalOptions = {
      delete_posts: true,
      delete_comments: true,
      delete_invites: true,
      ban_user: true
    }
  }

  *visibleMembers() {
    for (let el of Array.from(
      document.querySelectorAll(this.memberElementSelector)
    ).filter(el => !el.textContent.includes(this.adminText))) {
      yield el;
    }
  }

  openContextMenuForMember(memberEl) {
    if (memberEl.querySelector(this.memberContextMenuSelector) !== null) {
        memberEl.querySelector(this.memberContextMenuSelector).click();
    }
  }

  openRemoveMemberDialog() {
    const el = document.querySelector(this.removeMemberButtonSelector)
    
    if (el === null) {
        return false;
    }

    el.click();
    el.remove(); // clean up old element since querySelector picks the first one
  }

  setRemovalOptions() {
    for (let key in this.removalOptions) {
      const value = this.removalOptions[key];
      if (value === false) { return; }
      this.removeMemberModalEl
        .querySelector(`input[type="checkbox"][name="${key}"]`).click();
    }
  }

  confirmRemoveMember() {
    if (this.removeMemberModalEl) {
        this.removeMemberModalEl.querySelector('button').click();
    }
  }

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

  get removeMemberModalEl() {
    return Array.from(document.querySelectorAll('form'))
      .find(el => el.textContent.includes(this.removeMemberModalHeadingText))
  }

  async start() {
    for (let memberEl of this.visibleMembers()) {
      this.openContextMenuForMember(memberEl);
      await this.wait(100);
      this.openRemoveMemberDialog();
      await this.wait(1000);
      // this.setRemovalOptions(); // if you care about deleting posts etc
      // await this.wait(100);
      this.confirmRemoveMember();
    }
  }
}

const fbgmr = new FBGroupMemberRemover();
fbgmr.start();