A tampermonkey script to automatically set the playback on YouTube

playback-rate.js

// ==UserScript==
// @name         YouTube playback rate
// @namespace    https://lungers.com
// @version      0.1
// @description  Automatically set the playback on YouTube
// @author       Andrew Lane
// @match        https://www.youtube.com/watch?v=*
// @run-at       document-end
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    if (sessionStorage.hasOwnProperty('yt-player-playback-rate')) {
        console.log('Playback rate already set');
        return;
    }

    const channelSelector = '.ytd-video-owner-renderer';
    const artistSelector = '#upload-info .badge-style-type-verified-artist';
    const liveSelector = '#date .ytd-video-primary-info-renderer:not(#dot)';
    const ignoredChannels = [
        'UCa10nxShhzNrCE1o2ZOPztg', // Trap Nation
        'UCM9KEEuzacwVlkt9JfJad7g', // Chill Nation
        'UCj_Y-xJ2DRDGP4ilfzplCOQ', // House Nation
        'UC3ifTl5zKiCAhHIBQYcaTeg', // Proximity
        'UC_aEa8K-EOJ3D6gOs7HcyNg', // NCS
        'UCXO3dTkwiv6hDI5_MTZ8OuA', // Ma Fo
        'UCQtq9GX2WGDzvapvfIwkUyg', // Wandering Music
        'UCTOFODoILyXvkRdXtmepffA', // DEEPROT
    ];

    const observer = new MutationObserver((mutations, observer) => {
        mutations.forEach(mutation => {
            const channel = document.querySelector(channelSelector);
            const artistBadge = document.querySelector(artistSelector);
            const liveBadge = document.querySelector(liveSelector);
            if (!channel?.href) {
                return;
            }

            observer.disconnect();

            const channelID = new URL(channel.href).pathname.split('/').pop();
            if (ignoredChannels.includes(channelID)) {
                console.log('Not setting playback rate: ignored channel');
            } else if (artistBadge !== null) {
                console.log('Not setting playback rate: artist channel');
            } else if (liveBadge !== null && liveBadge.innerText.startsWith('Started streaming on ')) {
                console.log('Not setting playback rate: live stream');
            } else {
                sessionStorage.setItem('yt-player-playback-rate', `{"data":"1.25","creation":${Date.now()}}`);
                setTimeout(() => {
                    location.reload();
                }, 100);
            }
        });
    });

    observer.observe(document.body, {
        childList: true,
    });
})();