yt-sb-playlist-sort.js

// ==UserScript==
// @name		YouTube Sidebar Playlist Sorter (A-Z)
// @version		1.0.0
// @author		Tyler Sedlar
// @description	Sorts the YouTube sidebar playlists alphabetically
// @match		http://*.youtube.com/
// @match		https://*.youtube.com/
// @match		http://*.youtube.com/*
// @match		https://*.youtube.com/*
// ==/UserScript==
function ytText(element) {
  return element.getElementsByTagName('a')[0].title
}

function sortChildren(parent, comparator) {
  if (parent) {
    Array.prototype.slice.call(parent.children)
      .map(function(x) {
        return parent.removeChild(x)
      })
      .sort(function(x, y) {
        return comparator(x, y)
      })
      .forEach(function(x) {
        parent.appendChild(x)
      })
  }
}

var menu = document.querySelector("button[aria-label=Guide]")

if (menu) {
  menu.onclick = function() {
    setTimeout(function() {
      var btn = document.querySelector('a[title="Show more"]')
      if (btn) {
        btn.click()
        sortChildren(document.querySelector('#expandable-items'), function(x, y) {
          return ytText(x).localeCompare(ytText(y))
        })
      }
    }, 1500)
  }
}