A function that returns the duration of a YouTube video from the YouTube API V3.

fetchYTduration.js

function fetchDuration(videoId, apiKey) {
  const baseURL = 'https://www.googleapis.com/youtube/v3/videos?';
  const url = `${baseURL}id=${videoId}&key=${apiKey}&part=snippet,contentDetails`;
  $.ajax({
    async: false,
    type: 'GET',
    url: url,
    success: function(data) {
      const item = data.items[0];
      const result = item ? item.contentDetails.duration : null;
      return result;
    }
  });
}