js 获取本周开始结束时间，本月开始结束时间等....

var now = new Date(); // 当前日期
var nowDayOfWeek = now.getDay(); // 今天本周的第几天
var nowDay = now.getDate(); // 当前日
var nowMonth = now.getMonth(); // 当前月
var nowYear = now.getYear(); // 当前年
nowYear += (nowYear < 2000) ? 1900 : 0;
 
var DateUtil = {
    /**
     * 获得当前日期
     * 
     * @returns
     */
    getNowDay() {
        return this.formatDate(new Date());
    },
    /**
     * 获得本周的开始时间
     * 
     * @returns
     */
    getStartDayOfWeek() {
        var day = nowDayOfWeek || 7;
        return this.formatDate(new Date(now.getFullYear(), nowMonth, nowDay + 1 - day));
    },
    /**
     * 获得本周的结束时间
     * 
     * @returns
     */
    getEndDayOfWeek() {
        var day = nowDayOfWeek || 7;
        return this.formatDate(new Date(now.getFullYear(), nowMonth, nowDay + 7 - day));
    },
    /**
     * 获得本月的开始时间
     * 
     * @returns
     */
    getStartDayOfMonth() {
        var monthStartDate = new Date(nowYear, nowMonth, 1);
        return this.formatDate(monthStartDate);
    },
    /**
     * 获得本月的结束时间
     * 
     * @returns
     */
    getEndDayOfMonth() {
        var monthEndDate = new Date(nowYear, nowMonth, this.getMonthDays());
        return this.formatDate(monthEndDate);
    },
    /**
     * 获得本月天数
     * 
     * @returns
     */
    getMonthDays() {
        var monthStartDate = new Date(nowYear, nowMonth, 1);
        var monthEndDate = new Date(nowYear, nowMonth + 1, 1);
        var days = (monthEndDate - monthStartDate) / (1000 * 60 * 60 * 24);
        return days;
    },
    /**
     * @param 日期格式化
     * @returns {String}
     */
    formatDate(date) {
        var myyear = date.getFullYear();
        var mymonth = date.getMonth() + 1;
        var myweekday = date.getDate();
 
        if (mymonth < 10) {
            mymonth = "0" + mymonth;
        }
        if (myweekday < 10) {
            myweekday = "0" + myweekday;
        }
        return (myyear + "-" + mymonth + "-" + myweekday);
    }
};

export default{
    DateUtil
}