how to calculate mortgage in javascript

Question

I have formula for finding monthly payment with four fields

1. Loan Amount
2. Interest Rate
3. Terms of loan
4. Monthly Payment

Answer 1

This is the exact same answer as @shay gave but with the variable names spelled out to make it easier for me to understand:

// totalPayments should be the total number of payments expected to be made for the life of the loan: years * 12
// interestRate: eg. 6.2% should be passed as 0.062
function getMortgagePayment(startingLoanAmount, totalPayments, interestRate)
{
    let interestRatePerMonth = interestRate / 12;
    return startingLoanAmount * interestRatePerMonth * (Math.pow(1 + interestRatePerMonth, totalPayments)) / (Math.pow(1 + interestRatePerMonth, totalPayments) - 1);
}