youtube channel play all videos as playlist

youtube-play-all-playlist.js

let cId = document.querySelector('[itemprop="identifier"]').content;

const getPlaylistId = () => {
    let cId = document.querySelector('[itemprop="identifier"]').content;
    if(cId?.startsWith('UC')) return 'UU' + cId.slice(2);
    else return null;
}

const getPlaylistUrl = () => {
    let channelId = getPlaylistId();
    if(!channelId) {
        console.error("ERROR getting playlist ID.")
        return null;
    }
    return 'https://www.youtube.com/playlist?list=' + channelId
}

const playlistUrl = getPlaylistUrl();

// open in new tab.
if(playlistUrl) {
    console.log(playlistUrl);
    window.open(playlistUrl, '_blank');
}