Get an RSS pubDate from a Javascript Date instance.

gistfile1.js

/**
 * Get an RSS pubDate from a Javascript Date instance.
 * @param Date - optional
 * @return String
 */
function pubDate(date) {

  if (typeof date === 'undefined') {
    date = new Date();
  }

  var pieces     = date.toString().split(' '),
      offsetTime = pieces[5].match(/[-+]\d{4}/),
      offset     = (offsetTime) ? offsetTime : pieces[5],
      parts      = [
        pieces[0] + ',',
        pieces[2],
        pieces[1],
        pieces[3],
        pieces[4],
        offset
      ];

  return parts.join(' ');
}