Ring Central Google Calendar add dashes to ID (Tampermonkey)

userscript_gcal_rc_dashes.js

// ==UserScript==
// @name         Ring Central ID dashes
// @namespace    http://tampermonkey.net/
// @version      0.6
// @description  Add dashes to Ring Central meeting IDs in the "ID:" display
// @author       Jay Otterbein
// @match        https://calendar.google.com/calendar*
// @grant        none
// @updateURL    https://gist.githubusercontent.com/jayotterbein/9bc44309c15c48cbd4ac5147445ae1fa/raw/userscript_gcal_rc_dashes.js
// @homepageURL  https://gist.github.com/jayotterbein/9bc44309c15c48cbd4ac5147445ae1fa/userscript_gcal_rc_dashes.js
// ==/UserScript==

(function() {
    'use strict';

    const observer = new MutationObserver(mutationsList => {
        mutationsList.forEach(mutation => {
            mutation.addedNodes &&
                mutation.addedNodes.forEach(n => {
                n.querySelectorAll &&
                    n.querySelectorAll('div').forEach(el => {
                    const m = el.firstChild && el.firstChild.data && el.firstChild.data.match(/(ID|PIN|Passcode):\s+([0-9]{3})([0-9]{3})([0-9]{4})\s*/);
                    if (m) {
                        const u = `${m[1]}: ${m[2]}-${m[3]}-${m[4]}`;
                        el.innerText = u;
                    }
                });
            });
        });
    });
    observer.observe(document.body, { childList: true, subtree: true });
})();