Construct Test Cases
Construct 2+ test cases for each classification you created in the last step. Try to choose extreme cases. Finding the tricky cases is not easy and it will take practice. But spending the time to do this will help you understand the problem, find solution strategies, write robust code, and structure your development process.
After you have constructed your test cases, write them into "/tests/test-cases.js" in your repo. These are the tests your complete solution will have to pass.