实现日期格式化函数

Question

function formatDate(date, format) {
  let year = date.getFullYear();
  let month = date.getMonth() + 1;
  let day = date.getDate();
  let hour = date.getHours();
  let minute = date.getMinutes();
  let second = date.getSeconds();

  format = format.replace(/yyyy/g, year.toString());
  format = format.replace(/MM/g, (month < 10 ? '0' : '') + month.toString());
  format = format.replace(/dd/g, (day < 10 ? '0' : '') + day.toString());
  format = format.replace(/HH/g, (hour < 10 ? '0' : '') + hour.toString());
  format = format.replace(/mm/g, (minute < 10 ? '0' : '') + minute.toString());
  format = format.replace(/ss/g, (second < 10 ? '0' : '') + second.toString());

  return format;
}

1. 各个时间的获取函数，和处理方式