如何将字符串中的时间值从PT格式转换为秒？

function convertPTtoSeconds(timeString) {
  const regex = /P(\d+Y)?(\d+M)?(\d+D)?T?(\d+H)?(\d+M)?(\d+S)?/;
  const matches = timeString.match(regex);

  if (!matches) {
    return "Invalid PT format";
  }

  const [_, years, months, days, hours, minutes, seconds] = matches;

  let totalSeconds = 0;

  if (years) {
    totalSeconds += parseInt(years) * 365 * 24 * 60 * 60;
  }
  if (months) {
    totalSeconds += parseInt(months) * 30 * 24 * 60 * 60;
  }
  if (days) {
    totalSeconds += parseInt(days) * 24 * 60 * 60;
  }
  if (hours) {
    totalSeconds += parseInt(hours) * 60 * 60;
  }
  if (minutes) {
    totalSeconds += parseInt(minutes) * 60;
  }
  if (seconds) {
    totalSeconds += parseInt(seconds);
  }

  return totalSeconds;
}

const timeString = "P1Y2M3DT4H5M6S";
const totalSeconds = convertPTtoSeconds(timeString);
console.log(totalSeconds);