code: function numberWithCommas(n) {
    const parts = n.toString().split('.');
    parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, ',');
    return parts.join('.');
  }
docs: Converts a number to include commas, if necessary.
  
  Source: http://stackoverflow.com/a/2901298
  
  @private
  @param  {number|string} n
  @return {string}