如何在Javascript中将带有3个字母的时区缩写的日期转换为UTC？

function convertToUTC(dateString) {
  var date = new Date(dateString);
  var parts = date.toLocaleString("en-US", { timeZoneName: "short" }).split(" ");
  var datePart = parts[0];
  var timePart = parts[1];
  
  var [year, month, day] = datePart.split("-");
  var [hour, minute, second] = timePart.split(":");
  
  var utcTimestamp = Date.UTC(year, month - 1, day, hour, minute, second);
  var utcDate = new Date(utcTimestamp);
  
  return utcDate.toISOString();
}

// 示例用法
var dateString = "2022-01-01T12:34:56.789Z";
var utcString = convertToUTC(dateString);
console.log(utcString);