http://esola.co/posts/2017/gas-youtube-stats/

youtube-stats.gs

var API_KEY = '';
var VIDEO_ID = '';

function trigger() {
  getStats();
}

function getStats() {
  url = 'https://www.googleapis.com/youtube/v3/videos?id=' + VIDEO_ID + '&key=' + API_KEY + '&fields=items(statistics)&part=statistics'

  var response = UrlFetchApp.fetch(url);
  if (response.getResponseCode() != 200) {
    Logger.log("Error %s:", response);
    return;
  }

  var json = JSON.parse(response.getContentText());
  var stats = json['items'][0]['statistics'];
  
  as = SpreadsheetApp.getActiveSheet();
  lastRow = as.getLastRow();
  
  cell = as.getRange('A1');  
  
  var d = new Date();
  now = Utilities.formatDate(d, 'JST', 'M/d HH:mm');
  
  cell.offset(lastRow, 0).setValue(now); 
  cell.offset(lastRow, 1).setValue(stats['viewCount']); 
  cell.offset(lastRow, 2).setValue(stats['likeCount']);
  cell.offset(lastRow, 3).setValue(stats['dislikeCount']);
  cell.offset(lastRow, 4).setValue(stats['favoriteCount']);
  cell.offset(lastRow, 5).setValue(stats['commentCount']);
}