BC Mortgage Calculator API

author: Karl Bonnici (@kbonnici)

Overview

A mortgage calculator API which takes in the following inputs:

• Property price
• Down payment
• Annual interest rate
• Amortization period (5 year increments between 5 and 30 years)
• Payment schedule (accelerated bi-weekly, bi-weekly, monthly)

and produces the following outputs:

• Payment per payment schedule
• An error if the inputs are not valid

This API can be interacted with using the accompanying frontend application

Mortgage Payment Formula

M = P * (r * (1+r)^n)/((1 + r)^n - 1)

• M = Payment per payment schedule
• P = Principle
• r = per payment schedule interest rate. Calculated by dividing the annual interest rate by the number of payments per annum
• n = Total number of payments over the amortization period

How to Run

• First, run npm install
• To run the server, run npm start
• To watch for changes to code, run npm run dev
• To only build the project, run npm run build

Testing

• Unit tests: npm run test
• Integration tests: npm run integration
• Both: npm run test integration
• Coverage report: npx jest --coverage