fv.js

import { ERRORTYPES as error } from "./error";
import isblank from "./isblank";

export default function fv(rate, periods, payment, value = 0, type = 0) {

  if (isblank(rate)) return error.na;
  if (isblank(periods)) return error.na;
  if (isblank(payment)) return error.na;

  var fv;
  if (rate === 0) {
    fv = value + payment * periods;
  } else {
    var term = Math.pow(1 + rate, periods);
    if (type === 1) {
      fv = value * term + payment * (1 + rate) * (term - 1) / rate;
    } else {
      fv = value * term + payment * (term - 1) / rate;
    }
  }
  return -fv;
}