JavaScript关于操作时间段代码

/* 获取时间段内属于星期一(*)的日期们
     * begin: 开始时间
     * end：结束时间
     * weekNum：星期几 {number}
     */
    function getWeek (begin, end, weekNum){
        var dateArr = new Array();
        var stimeArr = begin.split("-");//=>["2018", "01", "01"]
        var etimeArr = end.split("-");//=>["2018", "01", "30"]

        var stoday = new Date();
        stoday.setUTCFullYear(stimeArr[0], stimeArr[1]-1, stimeArr[2]);
        var etoday = new Date();
        etoday.setUTCFullYear(etimeArr[0], etimeArr[1]-1, etimeArr[2]);

        var unixDb = stoday.getTime();//开始时间的毫秒数
        var unixDe = etoday.getTime();//结束时间的毫秒数

        for (var k = unixDb; k <= unixDe;) {
            let needJudgeDate = msToDate(parseInt(k)).withoutTime;
            //不加这个if判断直接push的话就是已知时间段内的所有日期
            if (new Date(needJudgeDate).getDay() === weekNum) {
                dateArr.push(needJudgeDate);
            }
            k = k + 24*60*60*1000;
        }
        return dateArr;
    }

    //根据毫秒数获取日期
    function msToDate (msec) {
        let datetime = new Date(msec);
        let year = datetime.getFullYear();
        let month = datetime.getMonth();
        let date = datetime.getDate();
        let hour = datetime.getHours();
        let minute = datetime.getMinutes();
        let second = datetime.getSeconds();

        let result1 = year +
            '-' +
            ((month + 1) >= 10 ? (month + 1) : '0' + (month + 1)) +
            '-' +
            ((date + 1) < 10 ? '0' + date : date) +
            ' ' +
            ((hour + 1) < 10 ? '0' + hour : hour) +
            ':' +
            ((minute + 1) < 10 ? '0' + minute : minute) +
            ':' +
            ((second + 1) < 10 ? '0' + second : second);

        let result2 = year +
            '-' +
            ((month + 1) >= 10 ? (month + 1) : '0' + (month + 1)) +
            '-' +
            ((date + 1) < 11 ? '0' + date : date);

        let result = {
            hasTime: result1,
            withoutTime: result2
        };

        return result;
    }

    function getDayByWeekDay(day) {
        if (day == '星期日') {
            return 0;
        } else if (day == '星期一') {
            return 1;
        } else if (day == '星期二') {
            return 2;
        } else if (day == '星期三') {
            return 3;
        } else if (day == '星期四') {
            return 4;
        } else if (day == '星期五') {
            return 5;
        } else if (day == '星期六') {
            return 6;
        }
    }

    /**
     * 获取两个日期之间所有的日期
     * @param start
     * @param end
     * @returns {[]}
     */
    function getBetweenDateStr(start,end){
        var result = [];
        var beginDay = start.split("-");
        var endDay = end.split("-");
        var diffDay = new Date();
        var dateList = new Array;
        var i = 0;
        diffDay.setDate(beginDay[2]);
        diffDay.setMonth(beginDay[1]-1);
        diffDay.setFullYear(beginDay[0]);
        result.push(start);
        while(i == 0){
            var countDay = diffDay.getTime() + 24 * 60 * 60 * 1000;
            diffDay.setTime(countDay);
            dateList[2] = diffDay.getDate();
            dateList[1] = diffDay.getMonth() + 1;
            dateList[0] = diffDay.getFullYear();
            if(String(dateList[1]).length == 1){dateList[1] = "0"+dateList[1]};
            if(String(dateList[2]).length == 1){dateList[2] = "0"+dateList[2]};
            result.push(dateList[0]+"-"+dateList[1]+"-"+dateList[2]);
            if(dateList[0] == endDay[0] && dateList[1] == endDay[1] && dateList[2] == endDay[2]){ i = 1;
            }
        };
        return result;
    }