Hide posts from those I'm not following in Facebook.

Get rid of those annoying posts from those i'm not following

// ==UserScript==
// @namespace    https://greasyfork.org/en/users/1291782-tran-huu-phu-cuong
// @name         Hide posts from those I'm not following in Facebook.
// @version      1.1
// @description  Get rid of those annoying posts from those i'm not following
// @match        https://www.facebook.com/*
// @grant        none
// @Author       Cuong Tran
// @license MIT
// ==/UserScript==

//Whenever the page changes
(function() {
    function onElementInserted(containerSelector, elementSelector, callback) {
        var onMutationsObserved = function(mutations) {
            mutations.forEach(function(mutation) {
                if (mutation.addedNodes && mutation.addedNodes.length) {
                    [].map.call(mutation.addedNodes, function(el) {
                        if (!el || !el.querySelector) return;
                        // console.log('New inserted element', el)

                        if (el.attributes['data-pagelet'] && el.attributes['data-pagelet'].value === 'FeedUnit_{n}') {
                          callback(el)
                        } else {
                          var elements = el.querySelectorAll(elementSelector);
                          for (var i = 0, len = elements.length; i < len; i++) {
                            callback(elements[i]);
                          }
                        }
                    });
                }
            });
        };

        var target = document.querySelector(containerSelector);
        var config = { childList: true, subtree: true };
        var MutationObserver = window.MutationObserver || window.WebKitMutationObserver;
        var observer = new MutationObserver(onMutationsObserved);
        observer.observe(target, config);
    }


    onElementInserted('body', 'div[data-pagelet="FeedUnit_{n}"]', function(element) {
        if(element.querySelector('div[role="button"]').innerHTML.contains('Follow')){
            element.firstChild.style.display = 'none';
            const newdiv = document.createElement('div');
            newdiv.innerHTML = `<div cmftsb="0"><div class="wbtn"><button>___</button></div><div class="wtxt">1 post hidden. Rule: UNFOLLOWING AUTHOR</div></div>`
            element.appendChild(newdiv);
        }
        // if (element.innerText.substring(0,2) !== 'Ad') return;
        // console.log(element);
        //    element.style.display = "none";
    });

})();