This chapter showed you how to change the in-memory strategy to a document-based database called MongoDB. We were able to see that we could still follow the testing strategy using the integration tests we have been evolving throughout this book, and getting fast feedback as well as writing better code.
We learned also the basics of Docker, so that we could use MongoDB through Docker rather than locally. The order-api is becoming more interesting and more complex. So, you are now able to create complex APIs using TypeScript and store the information on databases, such as MongoDB on Docker.
In the next chapter, we will improve our application even more by adding security to it.