javascript如何格式化时间戳函数（附代码）

 formatDate(v) {
 if (/^(-)?\d{1,10}$/.test(v))
 {
 v = v * 1000;
 } 
 else if (/^(-)?\d{1,13}$/.test(v))
 {
 v = v * 1;
 } 
 var dateObj = new Date(v); 
 var month = dateObj.getMonth() + 1; 
 var day = dateObj.getDate(); 
 var hours = dateObj.getHours(); 
 var minutes = dateObj.getMinutes(); 
 var seconds = dateObj.getSeconds(); 
 if(month<10){
 month = "0" + month;
 } 
 if(day<10){
 day = "0" + day;
 } 
 if(hours<10){
 hours = "0" + hours;
 } 
 if(minutes<10){
 minutes = "0" + minutes;
 } 
 if(seconds<10){
 seconds = "0" + seconds;
 } 
 var UnixTimeToDate = dateObj.getFullYear() + '-' + month + '-' +day + ' ' + hours + ':' + minutes + ':' + seconds; 
 return UnixTimeToDate;
 }