Decomposing components

Component composition is an activity that creates order; larger behavior out of smaller parts. We often need to move in the opposite direction during development. Even after development, we can learn how a component works by tearing the code apart and watching it run in different contexts. Component decomposition means that we're able to take the system apart and examine individual parts in a somewhat structured approach.

Maintaining and debugging components

Over the course of application development, our components accumulate abstractions. We do this to support a feature's requirement better, while simultaneously supporting some architectural property that helps us scale. The problem is that as the abstractions accumulate, we lose transparency into the functioning of our components. This is not only essential for diagnosing and fixing issues, but also in terms of how easy the code is to learn.

For example, if there's a lot of indirection, it takes longer...