Function cumprinc

cumprinc(
    rate: number,
    nper: number,
    pv: number,
    startPeriod: number,
    endPeriod: number,
    type: 0 | 1,
): number
Calculates the cumulative principal paid on a loan between a start period and an end period.

Remarks:
- Make sure that you are consistent about the units you use for specifying rate and nper. If you make monthly payments on a four-year loan at an annual interest rate of 12 percent, use 0.12 / 12 for rate and 4 * 12 for nper. If you make annual payments on the same loan, use 0.12 for rate and 4 for nper.
- If rate <= 0, nper <= 0, or pv <= 0, this function throws a RangeError.
- If startPeriod < 1, endPeriod < 1, or startPeriod > endPeriod, this function throws a RangeError.
Parameters
- rate: number
  The interest rate.
- nper: number
  The total number of payment periods.
- pv: number
  The present value.
- startPeriod: number
  The first period in the calculation. Payment periods are numbered beginning with 1.
- endPeriod: number
  The last period in the calculation.
- type: 0 | 1
  The timing of the payment. 0 (zero) = payment at the end of the period. 1 = payment at the beginning of the period.
Returns number
The cumulative interest paid
Example
```
cumprinc(0.09 / 12, 30 * 12, 125000, 13, 24, 0); // -934.10712342
```
- Defined in cumprinc.js:32