Bulk remove liked pages from facebook with JavaScript. (last rev. 2019, may not work anymore)

facebook_unliker.js

// first select all liked buttons
var buttons = document.getElementsByClassName('PageLikedButton');

// launch pop for liked button
for(let button of buttons){
    button.click();
};

// select unlike button parent to prevent timeline button clicks
var unlikes = document.getElementsByClassName('InterestListMenuDisconnect');

// get unlike button and launch click action
for(let unlike of unlikes){
    var pages = unlike.getElementsByClassName('itemLabel')[0];
    pages.click();
}