adds a nice title to Mozilla Try pages with an overview of the running revision

Mozilla Try Enhancer

// ==UserScript==
// @name        Mozilla Try Enhancer
// @namespace   http://code4fun.de
// @description adds a nice title to Mozilla Try pages with an overview of the running revision
// @include     https://tbpl.mozilla.org/*
// @grant       GM_addStyle
// @version     1
// ==/UserScript==

// normal chars: ✗ ↻ ✓ †
let classes = {
    'busted': '✗',
    'testfailed': '✗',
    'running': '↻',
    'pending': '↻',
    'retry': '↻',
    'success': '✓',
    'usercancel': '†',
/*    'busted': '💊',
    'testfailed': '💊',
    'running': '🏃',
    'pending': '🏃',
    'retry': '🏃',
    'success': '🏆',
    'usercancel': '🌑',
*/};

setInterval(function update_title () {
    let pushes = document.querySelectorAll('#pushes > li.push');
    pushes = Array.prototype.slice.call(pushes);
    
    // only take first one
    pushes = pushes.slice(0, 1);
    
    let count = {};
    
    for (let push of pushes) {
        for (let cls in classes) {
            let elems = push.querySelectorAll('.machineResult.'+cls);
            let abbrev = classes[cls];
            count[abbrev] = (count[abbrev] ? count[abbrev] : 0) + elems.length;
        }
    }
    
    let str = [];
    for (let abbrev in count) {
        str.push(abbrev+':'+count[abbrev]);
    }
    str = str.join(' | ');
    document.title = document.title.slice(0, document.title.indexOf('-') + 1) + ' ' + str;
}, 1000);