JS获取当月windows显示的日历(简易版本)

JS代码：

/**
 * 要求格式yyyy-MM
 * @param {Object} currentMonth 当前月份
 */
function getCalendar(currentMonth) {
	if(currentMonth.indexOf("-") < 0) {
		return;
	}
	var calendar = [];
	var myDate = currentMonth.split("-")[1] * 1;
	computeDate(currentMonth).forEach((item, index) => {
		var iscurrentmonth = false;
		if(myDate == item.split("-")[1] * 1) {
			iscurrentmonth = true;
		}
		calendar.push({
			"week": new Date(item).getDay() == 0 ? 7 : new Date(item).getDay(),
			"date": item,
			"iscurrentmonth": iscurrentmonth
		});
	});
	return calendar;
}

/**
 * 要求格式yyyy-MM
 * @param {Object} currentMonth 当前月份
 */
function computeDate(currentMonth) {
	if(currentMonth.indexOf("-") < 0) {
		return;
	}
	var myDate = currentMonth.split("-");
	// 上个月的需要显示的天数
	var preMonthDate = [];
	// 当月需要显示的天数
	var currentMonthDate = [];
	// 下个月需要显示的天数
	var nextMonthDate = [];
	// 显示的总格数
	var total = 6 * 7;
	var currentMonthDays = getMonthDays(myDate[0], myDate[1]);

	// 当前月1号是周几
	var week = (new Date(currentMonth + '-01').getDay() == 0 ? 7 : new Date(currentMonth + '-01').getDay()) - 1;
	// 存储上月要显示的日期
	if(week > 0) {
		var dateTime = new Date(currentMonth + "-01");
		for(var i = 0; i < week; i++) {
			dateTime = dateTime.setDate(dateTime.getDate() - 1);
			dateTime = new Date(dateTime);
			preMonthDate.push(getNowFormatDate(dateTime));
		}
		preMonthDate.reverse();
	}
	//console.info(preMonthDate);

	// 存储当月要显示的日期
	var currentTime = new Date(currentMonth + "-01");
	currentMonthDate.push(getNowFormatDate(currentTime));
	for(var i = 0; i < currentMonthDays - 1; i++) {
		currentTime = currentTime.setDate(currentTime.getDate() + 1);
		currentTime = new Date(currentTime);
		currentMonthDate.push(getNowFormatDate(currentTime));
	}
	//console.info(currentMonthDate);

	// 存储下个月的日期
	var nextDays = (total - currentMonthDays - week);
	if(nextDays > 0) {
		var nextYear = myDate[0];
		var nextMonth = myDate[1];
		if(myDate[1] >= 12) {
			nextMonth = 1;
			nextYear++;
		} else {
			nextMonth++;
		}
		var nextTime = new Date(nextYear + "-" + nextMonth + "-01");

		nextMonthDate.push(getNowFormatDate(nextTime));
		for(var i = 0; i < nextDays - 1; i++) {
			nextTime = nextTime.setDate(nextTime.getDate() + 1);
			nextTime = new Date(nextTime);
			nextMonthDate.push(getNowFormatDate(nextTime));
		}
	}
	//console.info(nextMonthDate);

	// 合并数据
	return preMonthDate.concat(currentMonthDate, nextMonthDate);
}

/**
 * 获取当月天数
 * @param {Object} year 年份
 * @param {Object} month 月份
 */
function getMonthDays(year, month) {
	return new Date(year, month, 0).getDate();
}

/**
 * 返回格式 yyyy-MM-dd
 * @param {Object} date
 */
function getNowFormatDate(date) {
	var seperator1 = "-";
	var year = date.getFullYear();
	var month = date.getMonth() + 1;
	var strDate = date.getDate();
	if(month >= 1 && month <= 9) {
		month = "0" + month;
	}
	if(strDate >= 0 && strDate <= 9) {
		strDate = "0" + strDate;
	}
	var currentdate = year + seperator1 + month + seperator1 + strDate;
	return currentdate;
}

使用方式：

例子：
getCalendar("2021-01")

结果如下：