Convert time to datetime format

Recently I learned to convert two kinds of time into date and time formats, which are summarized as follows:
1.

Date.prototype.format = function(format)
{
var o = {
            "M+" : this.getMonth()+1, //month
            "d+" : this.getDate(), //day
            "h+" : this.getHours(), //hour
            "m+" : this.getMinutes(), //minute
            "s+" : this.getSeconds(), //second
            "q+" : Math.floor((this.getMonth()+3)/3), //quarter
            "S" : this.getMilliseconds() //millisecond
        }
    if(/(y+)/.test(format))
    format=format.replace(RegExp.$1,(this.getFullYear()+"").substr(4 - RegExp.$1.length));
    for(var k in o)
    if(new RegExp("("+ k +")").test(format))
    format = format.replace(RegExp.$1,RegExp.$1.length==1 ? o[k] : ("00"+ o[k]).substr((""+ o[k]).length));
    return format;
}

After that, you can use the format method to determine the date and time format you need, such as:

var mydate=new Date().format('yyyy year mm month dd day hh:mm:ss');

2.

dateDigitToString = function (num) {
            return num < 10 ? '0' + num : num;
 var currentDate = new Date(),
            year = dateDigitToString(currentDate.getFullYear()),
            month = dateDigitToString(currentDate.getMonth() + 1),
            date = dateDigitToString(currentDate.getDate()),
            hour = dateDigitToString(currentDate.getHours()),
            minute = dateDigitToString(currentDate.getMinutes()),
            second = dateDigitToString(currentDate.getSeconds()),
            formattedDateString = year + '年' + month + '月' + date + '日 ' + hour + ':' + minute + ':' + second;

This method can only define one time and date format, which is relatively less widely used than the first one.