Modern applications increasingly interface with lots of external systems — third-party APIs, databases, message queues, etc. In some cases, we may have control over the shape of the data being transmitted, but in other cases we may be at the mercy of something else. If we're not careful, implementation details like the shape of the data and the naming of the fields can permeate throughout our code.

Fully utilizing static types, with all the safety they provide, can be a bit tricky when dealing with dynamic data — like JSON from an API call. Let's look at how to do this in TypeScript.