## Introduction

Finance.js makes it easy to incorporate common financial calculations into your application. The library is built on pure JavaScript without any dependencies.

This project is hosted on GitHub. You can report bugs and discuss features on the GitHub issues page. Finance.js is available for use under the MIT software license.

## Getting Started

`npm install financejs --save`

**or**

```
<li>Download or fork the repository from GitHub.</li>
<li>Extract the file finance.js from the project and include it in your application on the client side.</li>
```

## Example Usage

var Finance = require('financejs'); var finance = new Finance(); // To calculate Amortization finance.AM(20000, 7.5, 5, 0); // => 400.76

### Typescript

```
import { Finance } from 'financejs'
let finance = new Finance();
// To calculate Amortization
finance.AM(20000, 7.5, 5, 0);
// => 400.76
```

## Tests

`npm test`

## Available Methods

### Amortization

`finance.AM(principal, rate, total number of payments, type);`

Amortization is the paying off of debt with a fixed repayment schedule in regular installments over a period of time.^{1}

For total number of payments which are entered as years, `type`

takes a `0`

, whereas for months `type`

takes a `1`

.

```
#Total Number of Payments Type = Years
// e.g., If principal is $20,000, rate is 7.5%, total number of payments is 5, and payment type is 0 (years), monthly payment is $400.76.
```

finance.AM(20000, 7.5, 5, 0);
=> 400.76

#Total Number of Payments Type = Months
// e.g.,If principal is $20,000, rate is 7.5%, total number of payments is 60, and payment type is 1 (months), monthly payment is $400.76.

finance.AM(20000, 7.5, 60, 1);
=> 400.76

### Compound Annual Growth Rate (CAGR)

`finance.CAGR(beginning value, ending value, number of periods);`

Compound Annual Growth Rate (CAGR) is the year-over-year growth rate of an investment over a specified period of time.^{2}

`// e.g., If the beginning value is $10,000, the ending value is $19,500, and the number of periods is 3, the CAGR is 24.93%.`

finance.CAGR(10000, 19500, 3);
=> 24.93

### Compound Interest (CI)

`finance.CI(rate, compoundings per period, principal, number of periods);`

Compound Interest is the interest calculated on the initial principal and also on the accumulated interest of previous periods of a deposit or loan.^{3}

`// e.g., If rate is 4.3%, the compoundings per period is 4, the principal is $1,500, and the number of periods is 6, the compound interest is $1,938.84.`

finance.CI(4.3, 4, 1500, 6 );
=> 1938.84

### Discount Factor (DF)

`finance.DF(rate, number of periods);`

The Discount Factor (DF) is the factor by which a future cash flow must be multiplied in order to obtain the present value.^{4}

`// e.g., If rate is 10% and the number of periods is 6, the result is an array of discount factors: 1, 0.91, 0.827, 0.752, 0.684.`

finance.DF(10, 6);
=> 1, 0.91, 0.827, 0.752, 0.684

### Future Value (FV)

`finance.FV(rate, cash flow, number of periods);`

Future Value (FV) is the value of an asset or cash at a specified date in the future that is equivalent in value to a specified sum today^{5}

`// e.g., If rate is 0.5%, cash flow is $1,000, and the number of periods is 12, the FV is $1,061.68.`

finance.FV(0.5, 1000, 12);
=> 1061.68

### Internal Rate of Return (IRR)

`finance.IRR(initial investment, cash flows);`

Internal Rate of Return (IRR) is the discount rate often used in capital budgeting that makes the net present value of all cash flows from a particular project equal to zero.^{6}

`// e.g., If initial investment is -$500,000 and the cash flows are $200,000, $300,000, and $200,000, IRR is 18.82%.`

finance.IRR(-500000, 200000, 300000, 200000);
=> 18.82

### XIRR

`finance.XIRR(cash flows, dates, guess);`

XIRR is used to determine the Internal Rate of Return when the cash flows are at Irregular intervals.^{15}

`// e.g., If the cash flows are -$1,000 on 1st Nov 2015, -$100 on 01 Jul 2016 and $1,200 on 19 Jul 2016, the XIRR is 14.11%.`

finance.XIRR(-1000, -100, 1200,new Date(2015, 11, 1 ), new Date(2016, 7, 1 ), new Date(2016, 7, 19 ),0 );
=> 14.11

### Leverage Ratio (LR)

`finance.LR(total liabilities, total debts, total income);`

Leverage Ratio (LR) is used to calculate the financial leverage of a company or individual to get an idea of the methods of financing or to measure ability to meet financial obligations.^{7}

`// e.g., If total liabilities are $25, total debts are $10, and total income is $20, the leverage ratio is 1.75.`

finance.LR(25, 10, 20);
=> 1.75

### Net Present Value (NPV)

`finance.NPV(rate, initial investment, cash flows);`

Net Present Value (NPV) compares the money received in the future to an amount of money received today, while accounting for time and interest through the discount rate. It's based on the principal of time value of money (TVM), which explains how time affects monetary value.^{8}

`cash flows`

takes any number of projected cash flows.

`// e.g., If discount rate is 10%, initial investment is -$1,000, cash flow in year 1 is $200,000, year 2 is $300,000, and year 3 is $200,000, the NPV is $80,015.03.`

finance.NPV(10, -500000, 200000, 300000, 200000);
=> 80015.03

### Payback Period (PP)

`finance.PP(number of periods, cash flows);`

Payback Period (PP) is the length of time required to recover the cost of an investment.^{9}

`number of periods`

takes a `0`

value for even cash flows;

for uneven cash flows, `number of periods`

takes any number of projected periods.

`cash flows`

takes any number of projected cash flows.

```
#Even Cash Flows
// e.g., Because even cash flows have the same inflow during each period, we set 'number of periods' to '0.' If initial investment is -$105 and the annual cash flow is $25, the payback period is 4.2 years.
```

finance.PP(0, -105, 25);
=> 4.2

#Uneven Cash Flows
// e.g., If number of periods is 5, initial investment is -$50, and the cash flows are $10, $13, $16, $19, and $22 for each year, the payback period is 3.42 years.

finance.PP(5, -50, 10, 13, 16, 19, 22);
=> 3.42

### Present Value (PV)

`finance.PV(rate, cash flow, number of periods);`

Present Value (PV) is the current worth of a future sum of money or stream of cash flows given a specified rate of return.^{10}

`number of periods`

is optional and defaults to `1`

.

`// e.g., If rate is 5% and cash flow is $100, the PV is $95.24.`

finance.PV(5, 100);
=> 95.24

// e.g., If rate is 5%, cash flow is $100, and number of periods is 5, the PV is $78.35.

finance.PV(5, 100);
=> 95.24

### Profitability Index (PI)

`finance.PI(rate, initial investment, cash flows);`

Profitability Index (PI) is an index that attempts to identify the relationship between the costs and benefits of a proposed project through the use of a ratio calculated.^{11}

`cash flows`

takes any number of projected cash flows.

`// e.g., If rate is 10%, initial investment is -$40,000, cash flows are $18,000, $12,000, $10,000, $9,000, and $6,000, PI is 1.09.`

finance.PI(10, -40000, 18000, 12000, 10000, 9000, 6000);
=> 1.09

### Return on Investment (ROI)

`finance.ROI(initial investment, earnings);`

Return on Investment (ROI) is a simple calculation that tells you the bottom line return of any investment.^{12}

`// e.g., If initial investment is -$55,000 and the earnings are $60,000, the return on investment is 9.09%.`

finance.ROI(-55000, 60000);
=> 9.09

### Rule of 72 (R72)

`finance.R72(rate);`

Rule of 72 (R72) is a rule stating that in order to find the number of years required to double your money at a given interest rate, you divide the compound return into 72.^{13}

`// e.g., If annual rate is 10%, rule of 72 is 7.2 years.`

finance.R72(10);
=> 7.2

### Weighted Average Cost of Capital (WACC)

`finance.WACC(market value of equity, market value of debt, cost of equity, cost of debt, tax rate);`

Weighted Average Cost of Capital (WACC) is the rate that a company is expected to pay on average to all its security holders to finance its assets.^{14}

`// e.g., If market value of equity is $600,000, market value of debt is $400,000, cost of equity is 6%, cost of debt is 5%, and tax rate is 35%, WACC is 4.9%.`

finance.WACC(600000, 400000, 6, 5, 35);
=> 4.9

### Loan Payment Per Period (PMT)

`finance.PMT(fractional interest rate, number of payments, principal);`

Payment for a loan based on constant payments and a constant interest rate

`finance.PMT(0.02,36,-1000000);`

=> 39232.8526

### Inflation-adjusted Return

`finance.IAR(investment Return, inflation Rate);`

Measure the return taking into account the time period's inflation rate

`finance.IAR(0.08, 0.03)`

=> 4.85

### Contributing

Contributions are welcome to aid in the expansion of the library. In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality, and please lint and test your code.### To Do

- Expand library with more financial calculations
- Include edge cases in testing, if any

### Contributing

Contributions are welcome to aid in the expansion of the library. In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality, and please lint and test your code.### To Do

- Expand library with more financial calculations
- Include edge cases in testing, if any