在没有外部包的Javascript中将带有Timezone的时间戳字符串转换为UTC

function convertTimestampToUTC(timestamp) {
  // Step 1: Convert timestamp string to Date object
  var date = new Date(timestamp);

  // Step 2: Get timezone offset in minutes
  var timezoneOffset = date.getTimezoneOffset();

  // Step 3: Apply timezone offset to Date object
  date.setMinutes(date.getMinutes() - timezoneOffset);

  // Step 4: Convert Date object to UTC ISO string
  var utcString = date.toISOString();

  return utcString;
}

// Example usage
var timestampString = "2022-01-01T12:00:00+08:00";
var utcString = convertTimestampToUTC(timestampString);
console.log(utcString);