this.defaultTimeZone = (new Date).toString().split('(')[1].slice(0, -1);
this.timezone = options.timezone || this.defaultTimeZone;
// 2.4.4 改进版本
this.timezone = options.timezone || timeZoneAbbreviation();
function timeZoneAbbreviation() {
  var abbreviation, date, formattedStr, i, len, matchedStrings, ref, str;
  date = (new Date()).toString();
  formattedStr = ((ref = date.split('(')[1]) != null ? ref.slice(0, -1) : 0) || date.split(' ');
  if (formattedStr instanceof Array) {
    matchedStrings = [];
    for (var i = 0, len = formattedStr.length; i < len; i++) {
      str = formattedStr[i];
      if ((abbreviation = (ref = str.match(/\b[A-Z]+\b/)) !== null) ? ref[0] : 0) {
        matchedStrings.push(abbreviation);
      }
    }
    formattedStr = matchedStrings.pop();
  }
  return formattedStr;
}

((abbreviation = (ref = str.match(/\b[A-Z]+\b/)) !== null) ? ref[0] : 0)
(abbreviation = (ref = str.match(/\b[A-Z]+\b/)) !== null)
(abbreviation = (xxx) !== null)
(abbreviation = xxx !== null)
abbreviation 必然是布尔值，如果将 matchedStrings.push(abbreviation) 换成 matchedStrings.push(str) 更接近预期值。

// this.defaultTimeZone = (new Date).toString().split('(')[1].slice(0, -1);
this.defaultTimeZone = (new Date + '').split(' ').slice(-1)[0].replace(/\(|\)/g, '');
this.timezone = options.timezone || this.defaultTimeZone;