javascript 날짜 함수 정리

1. 8자리 날짜 string to date type

function str_to_date(str)
{
    var date_str = String(str);
    var year = date_str.substring(0,4);
    var month = date_str.substring(4,6);
    var date = date_str.substring(6,8);

    return new Date(Number(year), Number(month)-1, Number(date));
}

 

2-1. date type to string

function date_to_str(date)
{
    var year = date.getFullYear();
    var month = date.getMonth() + 1;
    var date = date.getDate();

    month = month > 9 ? month : "0" + month;
    date  = date > 9 ? date : "0" + date;
    return year + month + date;
}

2-2. date type to string, 구분점

function date_to_str(date, div)
{
    var year = date.getFullYear();
    var month = date.getMonth() + 1;
    var date = date.getDate();

    month = month > 9 ? month : "0" + month;
    date  = date > 9 ? date : "0" + date;
    return year + div + month + div + date;
}

 

3. 오늘 날짜

function get_today()
{
    return date_to_str(new Date());
}

 

4. 날짜 간 차이

function date_term(date_str1, date_str2)
{   
    time1 = str_to_date(date_str1).getTime() ;
    time2 = str_to_date(date_str2).getTime() ;

    var one_day = 1000 * 60 * 60 * 24;              // 1일 밀리초

    return Math.floor((time2-time1)/one_day);
}

 

5. 몇일 전, 몇달 전, 몇년 전

function before_date(str, b_y=0, b_m=0, b_d=0)
{
    var date_str = String(str);
    var year = date_str.substring(0,4);
    var month = date_str.substring(4,6);
    var date = date_str.substring(6,8);

    return new Date(Number(year)-b_y, Number(month)-1-b_m, Number(date)-b_d);
}

 

 

Date 객체는 시간까지 확장가능~!!