JSは、指定された日付に基づいて、その日付がある月曜日と日曜日を取得します.

/**
 * @param   （yyyy-mm-dd）
 * @author QC
 * @date 2018-03-15
 * */
getMonDayAndSunDay(datevalue) {
    let dateValue = datevalue;
    let arr = dateValue.split("-");
    //  -1      0       Date  
    let date = new Date(arr[0], arr[1] - 1, arr[2]);
    let dateOfWeek = date.getDay();//               （0～6--     ）
    let dateOfWeekInt = parseInt(dateOfWeek, 10);//     
    if (dateOfWeekInt == 0) {//     
        dateOfWeekInt = 7;
    }
    let aa = 7 - dateOfWeekInt;//          
    let temp2 = parseInt(arr[2], 10);// 10    ，    08 09      0
    let sunDay = temp2 + aa;//          
    let monDay = sunDay - 6;//          
    let startDate = new Date(arr[0], arr[1] - 1, monDay);
    let endDate = new Date(arr[0], arr[1] - 1, sunDay);
    let sm = parseInt(startDate.getMonth()) + 1;//  +1      0  
    let em = parseInt(endDate.getMonth()) + 1;
    //  alert("      ："+startDate.getFullYear()+"-"+sm+"-"+startDate.getDate());
    //  alert("      ："+endDate.getFullYear()+"-"+em+"-"+endDate.getDate());
    let start = startDate.getFullYear() + "-" + sm + "-" + startDate.getDate();
    let end = endDate.getFullYear() + "-" + em + "-" + endDate.getDate();
    let result = [];
    result.push(start);
    result.push(end);

    return result;
},
getDate() {
    let dt = new Date()
    let start = new Date(dt.getFullYear(), dt.getMonth(), 1)
    let start_ = new Date(this.getMonDayAndSunDay(start.Format('yyyy-MM-dd'))[0])
    let end = new Date(dt.getFullYear(), dt.getMonth() + 1, 5)
    let end_ = new Date(this.getMonDayAndSunDay(end.Format('yyyy-MM-dd'))[1])
    this.changeMonth(start_, end_);
},