function extractVideoIdFromUrl(url) {
  let videoId = url.split('v=')[1];
  let ampersandPosition = videoId.indexOf('&');
  if (ampersandPosition != -1) {
    videoId = videoId.substring(0, ampersandPosition);
  }   
 return videoId;
}
Extracts YouTube video ID from url.
(h/t https://stackoverflow.com/a/3452617)