mortgage-js/README.md

Javascript Mortgage Calculator

# mortgage-js
Simple mortgage calculator written in Javascript. Determine total monthly payment. Calculate entire payment schedule with principal and interest. See how additional principal payments could affect the pay down schedule. Also accounts for property tax, homeowner insurance and private mortgage insurance.

## Install with NPM
    npm install --save mortgage-js

## Usage
    mortgageJs = require("mortgage-js")
    
    let mortgageCalculator = mortgageJs.createMortgageCalculator();
    mortgageCalculator.totalPrice = 800000;
    mortgageCalculator.downPayment = 160000;
    mortgageCalculator.interestRate = 0.045;
    mortgageCalculator.months = 360;
    mortgageCalculator.taxRate = 0.012;
    mortgageCalculator.insuranceRate = 0.0013;
    mortgageCalculator.mortgageInsuranceRate = 0.010;
    mortgageCalculator.mortgageInsuranceEnabled = true;
    mortgageCalculator.mortgageInsuranceThreshold = 0.2;
    mortgageCalculator.additionalPrincipalPayment = 100;
    let payment = mortgageCalculator.calculatePayment();

## Alternate Usage
    mortgageJs = require("mortgage-js")
    
    let payment = mortgageJs.calculatePayment(800000,
            160000,
            0.045,
            360,
            0.012,
            0.0013,
            0.010,
            true,
            0.2,
            100);

## Payment Model
    {
        loanAmount: number, // Total loan amount. Price - Down Payment
        principalAndInterest: number, // Portion of payment that goes towards principal & interest.
        tax: number, // Property tax
        insurance: number, // Homeowner insurance
        total: number, // Total monthly payment
        termMonths: number, // Number of monthly payments
        mortgageInsurance: number, // Private mortgage insurance. Only relevant with lower down payments.
        paymentSchedule: [
            {
                count: number, // The payment number starting with 1
                interestPayment: number, // The portion of payment that is an interest charge
                totalInterest: number, // The total interest that has been paid thus far
                principalPayment: number, // The portion of payment that goes towards the principal balance
                totalPayment: number, // The total payment amount
                totalPayments: number, // The total of payments that have been made thus far
                balance: number // The remaining balance after payment has been applied
            }
        ]
    }

## Running Tests

    npm test

## Release

1. Commit changes
2. Increment version with: npm version major|minor|patch
3. Push changes to origin master
4. npm publish