Present Value formula matching Excel and Google Sheets written in Javascript

present_value.js

/**
 * Present Value formula as detailed in Google Sheets/Excel
 * @param {Number} rate - as a decimal not as a percentage per period
 * @param {Number} nper - total number of periods remaining, needs to be the same period as rate
 * @param {Number} pmt - amount paid per period
 * @param {Number} [fv=0] - future value of the annuity (default 0)
 * @param {Number} [type=0] - is payment in arrears, paid at the end of each period, (0) or in advance, paid at the start of each period (1) (default is 0 = arrears)
 * @returns {Number}
 */
function pv(rate, nper, pmt, fv = 0, type = 0) {
    if (rate === 0) return -((pmt * nper) + fv);
    if (type !== 0 && type !== 1) return null;

    // Calculate the present value of the annuity (payments).
    const pvAnnuity = pmt * (1 + rate * type) * (1 - Math.pow(1 + rate, -nper)) / rate;
    
    // Calculate the present value of the future value.
    const pvFV = fv * Math.pow(1 + rate, -nper);
    
    // The total present value is the sum of the PV of the annuity and the PV of the future value.
    // The result is negated to indicate cash outflow.
    return -(pvAnnuity + pvFV);
}