Hide old news on HN

hn-hide-old-new.user.js

// ==UserScript==
// @name         Hide old news
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Hides old articles on Hacker News
// @author       Mike M
// @match        https://news.ycombinator.com/
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    function addGlobalStyle (css) {
        var head, style
        head = document.getElementsByTagName('head')[0]
        if (!head) { return }
        style = document.createElement('style')
        style.type = 'text/css'
        style.innerHTML = css
        head.appendChild(style)
    }

    addGlobalStyle('tr.old-news:not(:hover), tr.old-news:not(:hover) + tr, tr.old-news:not(:hover) + tr + tr { opacity: 0.1; }');

    document.querySelectorAll('.storylink').forEach(node => {
        if (/\(\d+\)/.test(node.textContent)) {
            const tr = node.closest('tr');
            tr.classList.add('old-news');
        }
    });
})();