YouTube Subscription Sorter

yt-sub-sorter.user.js

// ==UserScript==
// @name         YouTube Subscription Sorter
// @version      0.3
// @author       Patrick Roberts
// @match        https://www.youtube.com/*
// @grant        none
// ==/UserScript==

(function() {
  'use strict';

  var masthead = document.querySelector('#masthead');
  var guide = document.querySelector('#guide-inner-content');

  if (masthead && masthead.onGuideToggleHover_ && !main()) {
    var observer = new MutationObserver(main);

    observer.observe(guide, { childList: true, subtree: true });
    masthead.onGuideToggleHover_();
  }

  function main() {
    var section = document.querySelectorAll('#items')[1];
    if (!section) return false;

    var showMore = section.querySelector('ytd-guide-collapsible-entry-renderer');
    if (!showMore || !showMore.fillRemainingListItems) return false;

    showMore.fillRemainingListItems();

    if (observer && observer.disconnect) observer.disconnect();

    var subscriptions = Array.from(section.querySelectorAll('ytd-guide-entry-renderer:not([id])'));
    subscriptions.pop(); // Browse channels

    var parents = subscriptions.map(function(subscription) {
      return subscription.parentElement;
    });

    sort(subscriptions, function(subscription) {
      return subscription.querySelector('a').title;
    }, new Intl.Collator().compare).forEach(function(subscription, index, array) {
      if (index === 0 || parents[index - 1] !== parents[index]) {
        parents[index].insertBefore(subscription, parents[index].firstElementChild);
      } else {
        parents[index].insertBefore(subscription, array[index - 1].nextElementSibling);
      }
    });

    return true;

    function sort(array, key, compare) {
      array.map(function(value) {
        return { key: key(value), value: value };
      }).sort(function(a, b) {
        return compare(a.key, b.key);
      }).forEach(function(entry, index) {
        array[index] = entry.value;
      });

      return array;
    }
  }
})();