두 날짜 일수 계산 & 주말 제외 일수 계산

// 두개의 날짜를 비교하여 차이를 알려준다.
function dateDiff(_date1, _date2) {
    var diffDate_1 = _date1 instanceof Date ? _date1 : new Date(_date1);
    var diffDate_2 = _date2 instanceof Date ? _date2 : new Date(_date2);
 
    diffDate_1 =new Date(diffDate_1.getFullYear(), diffDate_1.getMonth()+1, diffDate_1.getDate());
    diffDate_2 =new Date(diffDate_2.getFullYear(), diffDate_2.getMonth()+1, diffDate_2.getDate());
 
    var diff = Math.abs(diffDate_2.getTime() - diffDate_1.getTime());
    diff = Math.ceil(diff / (1000 * 3600 * 24));
 
    return diff;
}

// 두개의 날짜를 비교하여 차이를 알려준다.
function dateDiff(_date1, _date2) {
    let diffDate_1 = _date1 instanceof Date ? _date1 : new Date(_date1);
    let diffDate_2 = _date2 instanceof Date ? _date2 : new Date(_date2);
 
    diffDate_1 =new Date(diffDate_1.getFullYear(), diffDate_1.getMonth()+1, diffDate_1.getDate());
    diffDate_2 =new Date(diffDate_2.getFullYear(), diffDate_2.getMonth()+1, diffDate_2.getDate());

    let count = 0;

    while(true) {  


        let temp_date = diffDate_1;
        if(temp_date.getTime() > diffDate_2.getTime()) {
            console.log("count : " + count);
            break;
        } else {
            let tmp = temp_date.getDay();
            if(tmp == 0 || tmp == 6) {
                // 주말
                // console.log("주말");
            } else {
                // 평일
                // console.log("평일");
                count++;         
            }
            temp_date.setDate(diffDate_1.getDate() + 1); 
        }
    }

    let diff = Math.abs(diffDate_2.getTime() - diffDate_1.getTime());
    diff = Math.ceil(diff / (1000 * 3600 * 24));
 
    return diff;
}