javascript时间缀转时间字符串

/*
@desc：时间缀转时间字符串
@param time 时间缀，长度为10
@return 时间字符串 格式为：2018-06-10 22:00:00
*/
function timetostr(time){
this.time = time
/*
 @desc：内部方法，若数字小于10补0
 @param input 传入数值
 @return ret 格式化后的数值
 */
this.parsetime = function(input){
    var ret
    if(input >= 0 && input < 10){
        ret = ‘0‘+input
    }else{
        ret = input
    }
    return ret
}
/*
 @desc：主方法，获取转换后的时间
 @return ret 时间字符串，格式为：2018-06-10 22:00:00
 */
this.get = function(){
    var time = (this.time)?(this.time):(Math.round(new Date().getTime()/1000))
    var date = new Date(time*1000)
    var year = this.parsetime(date.getFullYear())
    var month = this.parsetime(date.getMonth())
    var day = this.parsetime(date.getDate())
    var hour = this.parsetime(date.getHours())
    var minute = this.parsetime(date.getMinutes())
    var second = this.parsetime(date.getSeconds())
    var ret = year+‘-‘+month+‘-‘+day+‘ ‘+hour+‘:‘+minute+‘:‘+second
    return ret
}
}

var timetostr = new timetostr(1528593779)
var ret = timetostr.get()
console.log(ret)

2018-05-10 09:22:59