Highlight unread messages in Outlook Web Access (Tampermonkey script)

owa-tampermonkey.js

// ==UserScript==
// @name         OWA improver
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        https://correoweb.mapama.es/*
// @grant        GM_addStyle
// ==/UserScript==

(function () {
    'use strict';

    GM_addStyle(`
        div.has-unread-message {
            font-weight: bold;
            background-color: #d0c7ff;
        }
    ` );

    let observer = new MutationObserver(mutationChecker);
    observer.observe(document.body, { attributes: true, childList: true });


    function mutationChecker(mutationList) {
        for (const mutation of mutationList) {
            removeUnreadTags();
            addUnreadTags();
        }
    }

    function addUnreadTags() {
        const unreadMessagesSelector = '[tempid^="id=emailslistviewpanel"] .ms-font-weight-semibold.ms-font-color-themePrimary';
        const unreadNodes = document.querySelectorAll(unreadMessagesSelector);
        Array.from(unreadNodes).forEach(el => el.parentElement.parentElement.classList.add('has-unread-message'));
    }

    function removeUnreadTags() {
        Array.from(document.getElementsByClassName('has-unread-message')).forEach(el => el.classList.remove('has-unread-message'));
    }


})();