Day to Date calculator

const dayCalculator = (addDay) => {

    if(addDay){
        let [currMonth, currDay, currYear] = new Date().toLocaleDateString("en-US").split("/");
        console.log({currDay})
        const day31 = /1|3|5|7|8|10|12/;
        const day30 = /4|6|9|11/;

        for (let i = 0; i < addDay; i++) {
            if (day31.test(currMonth.toString())) {
                if (currDay === 31) {
                    currDay = 1;
                    if (currMonth === 12) {
                        currMonth = 1;
                        currYear++;
                    } else {
                        currMonth++;
                    }
                } else {
                    currDay++;
                }
            } else if (day30.test(currMonth.toString())) {
                if (currDay === 30) {
                    currDay = 1;
                    if (currMonth === 12) {
                        currMonth = 1;
                        currYear++;
                    } else {
                        currMonth++;
                    }
                } else {
                    currDay++;
                }
            } else {
                if (currDay === 28) {
                    currDay = 1;
                    if (currMonth === 12) {
                        currMonth = 1;
                        currYear++;
                    } else {
                        currMonth++;
                    }
                } else {
                    currDay++;
                }
            }
        }
        return `${currDay}/ ${currMonth} / ${currYear}`;
    } else {
        return "please provide a number"
    }

};

console.log(dayCalculator(730));