JavaScript에서 ISO 8601 형식의 문자열을 생성하는 방법은 무엇입니까?

const date = new Date();
const isoString = date.toISOString();

function isoDate(msSinceEpoch) {
  const d = new Date(msSinceEpoch);
  return (
    d.getUTCFullYear() +
    '-' +
    (d.getUTCMonth() + 1).toString().padStart(2, 0) +
    '-' +
    d.getUTCDate().toString().padStart(2, 0) +
    'T' +
    d.getUTCHours().toString().padStart(2, 0) +
    ':' +
    d.getUTCMinutes().toString().padStart(2, 0) +
    ':' +
    d.getUTCSeconds().toString().padStart(2, 0)
  );
}

console.log(isoDate(Date.now()));

if (!Date.prototype.toISOString) {
  (function() {
    function pad(number) {
      const r = String(number);
      if (r.length === 1) {
        r = '0' + r;
      }
      return r;
    }

    Date.prototype.toISOString = function() {
      return (
        this.getUTCFullYear() +
        '-' +
        pad(this.getUTCMonth() + 1) +
        '-' +
        pad(this.getUTCDate()) +
        'T' +
        pad(this.getUTCHours()) +
        ':' +
        pad(this.getUTCMinutes()) +
        ':' +
        pad(this.getUTCSeconds()) +
        '.' +
        String((this.getUTCMilliseconds() / 1000).toFixed(3)).slice(2, 5) +
        'Z'
      );
    };
  })();
}