Factorial Division JS

function factorialDivision(num1, num2) {
    let firstNum = calcFactorial(num1);
    let secondNum = calcFactorial(num2);

    console.log((firstNum / secondNum).toFixed(2));

    function calcFactorial(n) {
        let res = 1;
        for (let i = n; i >1; i -= 2) {
            res *= i * (i - 1);
        }
        return res;
    }
}