This script helps watching playlists. It tracks the last video from a playlist that you've watched on this computer.
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// ==UserScript==
// @name YouTube: playlists playback tracker
// @namespace http://tampermonkey.net/
// @version 4
// @description This script helps watching playlists. It tracks the last video from a playlist that you've watched on this computer.
// @author Andrei Rybak
// @license MIT
// @match https://www.youtube.com/playlist?list=*
// @match https://www.youtube.com/watch?*&list=*
// @icon https://www.google.com/s2/favicons?sz=64&domain=youtube.com
// @grant GM.setValue
// @grant GM.getValue
// @grant GM.listValues
// @grant GM.deleteValue
// ==/UserScript==
/*
* Copyright (c) 2023 Andrei Rybak
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
(async function() {
'use strict';
const urlParams = new URLSearchParams(document.location.search);
// never change -- used as part of IDs in storage in user's browser
const STORAGE_KEY_PREFIX = "YT_PL_TRACKER_";
const STORAGE_KEY_VIDEO_SUFFIX = "_VIDEO";
const STORAGE_KEY_DATE_SUFFIX = "_DATE";
// number of milliseconds to wait, until a video is considered "watched"
const SAVE_DELAY = 60000;
// hack to wait for necessary parts of the UI to load, in milliseconds
const YOUTUBE_UI_LOAD_DELAY = 6000;
function warn(...toLog) {
console.warn("[playlist tracker]", ...toLog);
}
function log(...toLog) {
console.log("[playlist tracker]", ...toLog);
}
function videoStorageKey(id) {
return STORAGE_KEY_PREFIX + id + STORAGE_KEY_VIDEO_SUFFIX;
}
function dateStorageKey(id) {
return STORAGE_KEY_PREFIX + id + STORAGE_KEY_DATE_SUFFIX;
}
function dateToString(d) {
return d.toISOString().slice(0, "YYYY-MM-DD".length);
}
function videoInPlaylistUrl(videoId, listId) {
return `https://www.youtube.com/watch?v=${videoId}&list=${listId}`;
}
function createVideoTitle(videoId) {
let links = document.querySelectorAll("#contents.ytd-playlist-video-list-renderer h3 a");
for (let i = 0; i < links.length; i++) {
const link = links[i];
if (link.href.includes(videoId)) {
return link.title;
}
}
// fallback is needed, because as of 2023-02-04 YouTube only loads 100 videos
// into the playlist controls, unless the user scrolls through it
return videoId;
}
function createLink(videoId, listId, date) {
const newLink = document.createElement("a");
newLink.id = 'YT_PL_TRACKER_LINK';
newLink.href = videoInPlaylistUrl(videoId, listId);
const videoTitle = createVideoTitle(videoId);
newLink.innerText = `Continue watching "${videoTitle}" from ${date}.`;
newLink.style = `color: white;`;
return newLink;
}
async function displaySavedVideoIndex(listId) {
log("Displaying saved video index...");
if (!listId) {
warn("Can't find parameter 'list' in the URL. Aborting.");
return;
}
const maybeVideoId = await GM.getValue(videoStorageKey(listId));
if (!maybeVideoId) {
log(`No video stored for list ${listId} yet.`);
return;
}
const date = await GM.getValue(dateStorageKey(listId));
log(`Showing stored video ${maybeVideoId} from date ${date}. Waiting for ${YOUTUBE_UI_LOAD_DELAY} ms...`);
setTimeout(() => { // stupid way of waiting until YouTube UI loads
log("Starting actual HTML edit...");
const header = document.querySelector(".metadata-buttons-wrapper");
const newLink = createLink(maybeVideoId, listId, date);
log("newLink =", newLink);
header.appendChild(newLink);
log("HTML edit finished.");
}, YOUTUBE_UI_LOAD_DELAY);
}
async function storeVideo(listId, videoId) {
log(`Storing ${videoId} as video for list ${listId}.`);
await GM.setValue(videoStorageKey(listId), videoId);
await storeDate(listId);
}
async function storeDate(listId) {
const dateStr = dateToString(new Date());
await GM.setValue(dateStorageKey(listId), dateStr);
}
function removePrefixSuffix(s, pref, suf) {
return s.slice(pref.length, -suf.length);
}
async function clearOldVideos() {
const keys = await GM.listValues();
log("Clearing old videos...");
const currentYear = new Date().getFullYear();
for (const key of keys) {
if (!key.endsWith(STORAGE_KEY_DATE_SUFFIX)) {
continue;
}
const dateKey = key;
const dateStr = await GM.getValue(dateKey);
const listId = removePrefixSuffix(dateKey, STORAGE_KEY_PREFIX, STORAGE_KEY_DATE_SUFFIX);
const videoKey = videoStorageKey(listId);
if (!dateStr) {
// clean up corrupted data, etc
GM.deleteValue(dateKey);
GM.deleteValue(videoKey);
continue;
}
const year = parseInt(dateStr.slice(0, "YYYY".length));
log(`Checking ${dateKey} -> ${dateStr} -> ${year} -> ${listId}`);
if (year < currentYear - 3) {
const videoId = await GM.getValue(videoKey);
const url = videoInPlaylistUrl(videoId, listId);
log(`Deleting outdated list ${listId} -> ${url} on date ${dateStr}`);
GM.deleteValue(dateKey);
GM.deleteValue(videoKey);
}
}
}
log("document.location.pathname =", document.location.pathname);
const listId = urlParams.get('list');
if (document.location.pathname == "/playlist") {
displaySavedVideoIndex(listId);
setTimeout(clearOldVideos, SAVE_DELAY);
}
const videoId = urlParams.get('v');
if (document.location.pathname == "/watch" && videoId && listId) {
// only store a video after it was watched for a minute (for debugging only 2-5 seconds)
setTimeout(() => {
storeVideo(listId, videoId);
clearOldVideos();
}, SAVE_DELAY);
}
log("Done");
})();