Inside an application, there are multiple components. Their code is divided into other subcomponents, such as modules or packages, and the modules into classes or functions, and the classes into methods. Throughout the book, the emphasis has been on keeping these components as small as possible, particularly in the case of functions—functions should do one thing, and be small.
Several reasons were presented to justify this rationale. Small functions are easier to understand, follow, and debug. They are also easier to test. The smaller the pieces in our code, the easier it will be to write unit tests for it.
For the components of each application, we wanted different traits, mainly high cohesion, and low coupling. By ...
