微信小程序实现日期格式化和倒计时

Date.prototype.Format = function (fmt) { //author: meizz 
 var o = {
  "M+": this.getMonth() + 1, //月份 
  "d+": this.getDate(), //日 
  "h+": this.getHours(), //小时 
  "m+": this.getMinutes(), //分 
  "s+": this.getSeconds(), //秒 
  "q+": Math.floor((this.getMonth() + 3) / 3), //季度 
  "S": this.getMilliseconds() //毫秒 
 };
 if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
 for (var k in o)
 if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
 return fmt;
 
}

formatDateTime:function(theDate) {
 var _hour = theDate.getHours();
 var _minute = theDate.getMinutes();
 var _second = theDate.getSeconds();
 var _year = theDate.getFullYear()
 var _month = theDate.getMonth();
 var _date = theDate.getDate();
 if (_hour < 10) { _hour ="0" + _hour }
 if (_minute < 10) { _minute = "0" + _minute }
 if (_second < 10) { _second = "0" + _second }
 _month = _month + 1
 if (_month < 10) { _month = "0" + _month; }
 if (_date < 10) { _date ="0" + _date }
 var time= _year + "-" + _month + "-" + _date + " " + _hour + ":" + _minute + ":" + 
 _second;
// var time = new Date();
// var formatTime = formatDateTime(time);
// 返回结果：
// Tue Jun 06 2017 15:31:09 GMT+ 0800(中国标准时间)
// 2017 - 06 - 06 15:31:09
//clock为在data中定义的空变量，存放转化好的日期
 this.setData({
 clock: time
 })
},

var formatTimeS = new Date('2017-06-06 15:31:09').getTime();

var formatTimeS = new Date(1496734269900);

//倒计时:其中time_canshu为传入的毫秒数
date_format: function (time_canshu) {
 // let formatTime1 = new Date().getTime();
 // let formatTime2 = new Date('2018-04-24 15:31:09').getTime();
 // let formatTimeS = new Date(formatTime2 - formatTime1);
 var none = '00:00:00';
 if (formatTimeS<=0){
 this.setData({
 clock: none
 })} else {
 // 秒数
 letsecond = Math.floor(time_canshu / 1000);
 // 小时位
 lethr = Math.floor(second / 3600);
 // 分钟位
 letmin = Math.floor((second - hr * 3600) /60);
 // 秒位
 letsec = second % 60;// equal to => var sec = second % 60;
 if (hr <= 9) hr ='0' + hr;
 if (min <= 9) min ='0' + min;
 if (sec <= 9) sec ='0' + sec;
 lettime = hr + ":" + min + ":" + sec + " ";
 this.setData({
 clock: time
 })
 }
},

//时间戳转化为日期格式
function timestampToTime(timestamp) {
  var date = new Date(timestamp * 1000);//时间戳为10位需*1000，时间戳为13位的话不需乘1000
  var Y = date.getFullYear() + '-';
  var M = (date.getMonth()+1 < 10 ? '0'+(date.getMonth()+1) : date.getMonth()+1) + '-';
  var D = date.getDate() + ' ';
  var h = date.getHours() + ':';
  var m = date.getMinutes() + ':';
  var s = date.getSeconds();
  return Y+M+D+h+m+s;
 }
 timestampToTime(1403058804);
 console.log(timestampToTime(1403058804));//2014-06-18 10:33:24
 
//日期格式转化为时间戳
var date = new Date('2014-04-23 18:55:49:123');
 // 有三种方式获取
 var time1 = date.getTime();
 var time2 = date.valueOf();
 var time3 = Date.parse(date);
 console.log(time1);//1398250549123
 console.log(time2);//1398250549123
 console.log(time3);//1398250549000
//以上三种获取方式的区别：第一、第二种：会精确到毫秒第三种：只能精确到秒，毫秒用000替代以上三个输出结果可观察其区别注意：获取到的时间戳除以1000就可获得Unix时间戳，就可传值给后台得到。

secondToDate (result) {
  if (result > 60) {
  let d = parseInt(Math.floor(result / 86400))
  let h = d > 0? Math.floor((result - d * 86400) / 3600): Math.floor(result / 3600);
  let m = h > 0? Math.floor((result - d * 86400 - h * 3600) / 60): Math.floor(result / 60);
  return d + '天:' + h + '时:' + m + '分'
  } else {
  return result + '秒'
  }
 }