Hide gmail inbox when empty, v0.1

hide_or_display_index.js

// ==UserScript==
// @name         Gmail Inbox Empty Reward
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  Hides much of the Gmail UI when your inbox is empty, to give you a little reward for reaching Inbox Zero!
// @author       Nate Berkopec
// @include       http://mail.google.com/*
// @include       https://mail.google.com/*
// @include       http://*.mail.google.com/*
// @include       https://*.mail.google.com/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
    function hideOrDisplayInbox() {
        var inbox = document.querySelector('.nH.bkK.nn');
        if (inbox && inInboxView() && isInboxEmpty()) {
            hideInbox(inbox);
        } else {
            showInbox(inbox);
        };
    };

    function hideInbox(inbox) {
        inbox.style.transition = 'opacity 2s';
        inbox.style.opacity = '0';
    };

    function showInbox(inbox) {
        inbox.style.opacity = '1';
    };

    function inInboxView() {
        return !!document.querySelector(".aim.ain [data-tooltip~='Inbox']"); // this is the inbox icon, we're asking if its highlighted or not
    };

    function isInboxEmpty() {
        return !document.querySelector(".aE3 .Cp tbody tr"); // rows inside your inbox
    };

    window.onload = function () { window.setInterval(hideOrDisplayInbox, 500) };
})();