Unlike All Facebook Pages

fb_unlike_all.js

// Run it at your own risk!!
// If you have been on Facebook since 2004 and happened to like ton of pages and wanna get rid of them all at once...
// Navigate to https://www.facebook.com/pages/?category=liked and run the the following snippet in the developer console...
var fb_unlike_all = () => {
  [].slice
    .call(document.querySelectorAll("button"))
    .filter((x) => x.innerText.indexOf("Liked") != -1)
    .map((x) => {
      x.click();
    });
  window.scrollTo(0, document.body.scrollHeight);
  window.setTimeout(fb_unlike_all, 3 * 1000);
};
fb_unlike_all();

Nice one. In case this doesn't work for others, I had to add 2 things:

1. Selectors for FB's classnames (which will change every release so you will need to update the querySelectorAll unfortunately)
2. "Unlike" AND "Unfollow" pages, depending on which verb the button uses

Updated version:

// If you have been on Facebook since 2004 and happened to like ton of pages and wanna get rid of them all at once...
// Navigate to https://www.facebook.com/pages/?category=liked and run the the following snippet in the developer console...
var fb_unlike_all = () => {
  [].slice
    .call(
      document.querySelectorAll(
        // You'll probably have to dig into inspector to update this for yourself unfortunately, it will change on every FB release
        ".om3e55n1.g4tp4svg.alzwoclg.jez8cy9q.jcxyg2ei.i85zmo3j.sr926ui1.jl2a5g8c.k7n6ui8p.b41d885q.hmqrhxox.got7tec9.frfouenu.bonavkto.djs4p424.r7bn319e.bdao358l.aesu6q9g.e4ay1f3w.dqxcxcok.ed17d2qt"
      )
    )
    .filter((x) => x.innerText === "Liked" || x.innerText === "Following")
    .map((x) => {
      x.click();
    });
  window.scrollTo(0, document.body.scrollHeight);
  window.setTimeout(fb_unlike_all, 3 * 1000);
};
fb_unlike_all();