Mortgage details are hard-coded into index.js.
The following is an example of what the console output is like.
> npm install
> npm start
Fixed monthly payments: 575.44
Remaining balance after 6 months: 94394.46
Amortization table:
+-------+---------+----------------+---------------+----------------+----------+
| Month | Payment | Principal Paid | Interest Paid | Total Interest | Balance |
+-------+---------+----------------+---------------+----------------+----------+
| 0 | 575.44 | 265.44 | 310 | 310 | 95734.56 |
| 1 | 575.44 | 266.3 | 309.14 | 619.14 | 95468.26 |
| 2 | 575.44 | 267.16 | 308.28 | 927.42 | 95201.1 |
| 3 | 575.44 | 268.02 | 307.42 | 1234.84 | 94933.08 |
etc.
The tests check the logic of functions in mortgage.js. In particular, mathematical consistency of mortgage.amortizationTable() is ensured, in which rounding errors are a common issue.
Run npm test. Requires mocha.