Google Apps Script function to change a YouTube video's privacy status

update-youtube-privacy.gs

// schedule this Google Apps Script function to run at a certain time to change a YouTube video's privacy status
function updateVideoPrivacy() { // enable the YouTube Data API under "Services"
  var channels = YouTube.Channels.list('contentDetails', {mine: true});
  for (var i=0; i<channels.items.length; i++) {
    var uploadsPlaylistId = channels.items[i].contentDetails.relatedPlaylists.uploads;
    var playlistResponse = YouTube.PlaylistItems.list('snippet', {playlistId: uploadsPlaylistId, maxResults: 1}); // or more than 1 if needed
    var video = playlistResponse.items[0]; // the first video in the list we retrieved
    var metadata = {
      status: {'privacyStatus': 'private'}, // public, unlisted, private 
      id: video.snippet.resourceId.videoId}; // we need to include the video ID from the playlist response
    YouTube.Videos.update(metadata, 'id,status') // update the video's privacy status
  }
}