amortizejs v1.0.3

AmortizeJS

Loan calculation and amortization schedule utility with support for custom amortization methods, available for node and browser.

AmortizeJS.calculate({
    method:   'mortgage', 
    apr:      3.5, 
    balance:  280350, 
    loanTerm: 60,
    startDate: new Date('December 24 2017')
});

Table of Contents

1. Features
2. Installation
3. Quickstart
4. API Docs
   • AmortizeJS
   • CalculatorConfig
   • AmortizationMethod
   • Payment
5. Formatting of results in examples
6. Contributing

Features

• Periodic payment calculation
• Total interest calculation
• Total payment calculation
• Calculate a payment's interest amount, principal amount and remaining balance
• Amortization schedule creation with optional payment date support
• Easily customize and create new amortization methods

Supported amortization methods

• Mortgage-Style/Constant-Payment method

Installation

Using Bower:

$ bower install amortizejs

<script src="./bower_components/AmortizeJS/dist/web/bundle.js"></script>

Using npm:

$ npm install amortizejs

Usage

In Browser: AmortizeJS class is available on the window object.

In Node.js

var AmortizeJS = require('amortizejs').Calculator;

Quickstart

To calculate a mortgage amortization schedule including payment dates:

var mortgage = AmortizeJS.calculate({
    method:   'mortgage',
    apr:      3.5, 
    balance:  280350,    
    loanTerm: 60,         
    startDate: new Date('December 24 2017')
});

console.log( mortgage.periodicPayment );    // 5100.06
console.log( mortgage.periodicInterest );   // 0.00292
console.log( mortgage.totalInterest );      // 25653.34
console.log( mortgage.totalPayment );       // 306003.34
console.log( mortgage.endDate );            // Sat Dec 24 2022 00:00:00 GMT-0500 (EST)
console.log( mortgage.schedule );           // [{"interest": 817.69, "principal": 4282.37, "remainingBalance": 276067.63, "date":"2017-12-24T05:00:00.000Z"} ...]

To retrieve list of available amortization methods:

AmortizeJS.availableMethods(); // ['mortgage']

API Docs

AmortizeJS

CalculatorConfig

An object conforming to the CalculatorConfig Interface is required when calling AmortizeJS.calculate(config), the following options are available:

AmortizationMethod

An object conforming to the AmortizationMethod Interface is returned when calling AmortizeJS.calculate(config), the following attributes are available on it:

Payment

A payment for the loan, will include the following:

Formatting of results in examples

Results are not truncated or formatted in any way, the results in the examples are truncated for clarity.

Contributing

It is easy to extend AmortizeJS with custom amortization methods, all you need to do is create a javascript class or function that can be initiated via the new operator. This constructor will be supplied the following arguments in order:

The constructor should return an object that conforms to the AmortizationMethod interface.

Using a custom method

function customFunction(balance, periodicInterest, loanTerm, startDate){
    //Your custom amortization algorithm here
    return arguments;
}

var mortgage = Calculator.calculate({
    method:   customFunction,
    apr:      3.5, 
    balance:  280350, 
    loanTerm: 60,
    startDate: new Date('December 24 2017')
});

console.log(mortgage); //{"0": 280350, "1": 0.00292, "2": 60, "3": "2017-12-24T05:00:00.000Z"}

Using a custom class

class CustomMethod{
    constructor(balance, periodicInterest, loanTerm, startDate){
        //Your custom amortization algorithm here
        return arguments;
    }
}

var mortgage = Calculator.calculate({
    method:   CustomMethod,
    apr:      3.5, 
    balance:  280350, 
    loanTerm: 60,
    startDate: new Date('December 24 2017')
});

console.log(mortgage); //{"0": 280350, "1": 0.00292, "2": 60, "3": "2017-12-24T05:00:00.000Z"}