计算指定年的某月有多少天

function getDays(year,month){

    var month = Number(month) - 1;

    let days = [31,28,31,30,31,30,31,31,30,31,30,31];//把12个月的天数固定成数组

    if((year % 4 ===0) && (year %100 !==0 || year & 400 ===0)){//计算闰年将2月改成29天

        days[1] = 29

    }

        return days[month]

}

console.log(getDays(2022,2));