Youtube playlists - email notification when new videos are posted

check_youtube_playlist_videos.gs

// INSTRUCTIONS
// 1. Go to https://script.google.com/ and make a new project
// (optional: rename it too, so you remember what it is later...)
// 2. Paste in this script and add your email and playlist IDs below (see note [1])
// 3. Save the script and do a test run to set up the permissions
// 4. Set up a trigger to run the check_playlists_youtube function every day

function check_playlists_youtube() {
  // OPTIONS: specify playlists to check and email to notify
  const PLAYLISTS = {
    'Joanna Stern WSJ': "PLqQNt9DP_BNAU8c1KroIe-PAmrhu-7Xcn"
  }; // format: 'your title': 'playlist id'
  const EMAIL_ADDRESS = "[email protected]"; // put your email here
  const SAFETY_BUFFER = 1; // overlap between checks, in hours (see note [2])

  // check playlists
  const MAX_RESULTS = 50;
  let new_videos = [];
  
  for (let [playlist_name, playlist_id] of Object.entries(PLAYLISTS)) {
    // get recent playlist entries
    let playlist_items = YouTube.PlaylistItems.list("snippet", {
      playlistId: playlist_id,
      maxResults: MAX_RESULTS
    });

    // check if there are any new videos from the last 24h
    let newest_video_date = new Date(playlist_items.items[0].snippet.publishedAt);
    if ((new Date() - newest_video_date)/1000/60/60 < (24 + SAFETY_BUFFER)) {
      new_videos.push({
        'playlist_name': playlist_name,
        'video_title': playlist_items.items[0].snippet.title,
        'video_link': "https://www.youtube.com/watch?v=" + 
          playlist_items.items[0].snippet.resourceId.videoId
      });
    }
  }

  // send email alert if there are new videos
  const RE_HTML = /<\/?([bp]|br)>/gi

  if (new_videos.length > 0) {
    let video_noun = new_videos.length > 1 ? 'videos' : 'video';
    let email_subject = `${new_videos.length} new playlist ${video_noun}: ` + 
      Array.from(new Set(new_videos.map(x => x.playlist_name))).join(", ");
    let email_body_lines = [`<p><b>New playlist ${video_noun}:</b></p>`];
    for (let video of new_videos) {
      email_body_lines.push(`<p><b>${video.playlist_name}</b><br>\n` + 
        `Title: ${video.video_title}<br>\n` + `Link: ${video.video_link}`);
    }
    let email_body = email_body_lines.join(`\n\n`);
    GmailApp.sendEmail(EMAIL_ADDRESS, email_subject, 
      email_body.replace(RE_HTML, ''), { htmlBody: email_body });
  }  
}

/*
NOTES
-----
[1]: If you don't know how to get the id for your playlist, it's the 'list' parameter
in the URL of the playlist page. For example, the URL for "Tech Things with Joanna
Stern" is https://www.youtube.com/playlist?list=PLqQNt9DP_BNAU8c1KroIe-PAmrhu-7Xcn
and the playlist id is 'PLqQNt9DP_BNAU8c1KroIe-PAmrhu-7Xcn'.

You can check multiple playlists by setting up your list like this:
const PLAYLISTS = {
    'Your Title A': "long_id_A",
    'Your Title B': "long_id_B",
    ...
    'Your Title Z': "long_id_Z"
  };

[2]: Daily triggers run at some point within in a one-hour window each day,
so adding a safety buffer of one hour makes sure you don't miss any videos
if the trigger runs early one day and late the next. You may get two notifications
for the same video if that video was published during the hour your trigger runs,
but this shouldn't be too common.
*/