带你读《现代Javascript高级教程》二十三、Date类：日期和时间处理（2）

Date.prototype.toISODate = function() {
  const year = this.getFullYear();
  const month = String(this.getMonth() + 1).padStart(2, '0');
  const day = String(this.getDate()).padStart(2, '0');
  return `year−{year}-{month}-${day}`;};
// 使用示例const date = new Date();const isoDate = date.toISODate();
console.log(isoDate);

Date.prototype.getDaysDiff = function(otherDate) {
  const oneDay = 24 * 60 * 60 * 1000; // 一天的毫秒数
  const diffInTime = Math.abs(this - otherDate);
  const diffInDays = Math.round(diffInTime / oneDay);
  return diffInDays;};
// 使用示例const date1 = new Date('2022-01-01');const date2 = new Date('2022-01-10');const daysDiff = date1.getDaysDiff(date2);
console.log(daysDiff); // 输出 9

Date.prototype.getFirstDayOfMonth = function() {
  const year = this.getFullYear();
  const month = this.getMonth();
  return new Date(year, month, 1);};
Date.prototype.getLastDayOfMonth = function() {
  const year = this.getFullYear();
  const month = this.getMonth() + 1;
  return new Date(year, month, 0);};
// 使用示例const date = new Date();const firstDayOfMonth = date.getFirstDayOfMonth();const lastDayOfMonth = date.getLastDayOfMonth();
console.log(firstDayOfMonth);
console.log(lastDayOfMonth);