structural-design-principles

Reduce coupling by applying composition over inheritance, the Law of Demeter to minimize chaining, and encapsulation to push logic to owning modules. These structural design principles clarify boundaries and enforce minimal dependencies across Elixir, TypeScript, React, and multi-paradigm codebases.

Composition builds behavior by combining smaller, independent modules rather than inheriting from parent classes. This approach avoids tight hierarchies, improves testability, and lets you compose behaviors dynamically—critical for refactoring and dependency management in large systems.

Tell, Don't Ask: push decision logic into the module that owns the data, and expose only what's necessary through its API. Pair this with the Law of Demeter to avoid deep chaining. This protects internals, clarifies responsibilities, and improves interface clarity.

Yes. Composition, encapsulation, and the Law of Demeter are universal principles that work across paradigms. They apply to Elixir modules, TypeScript components, React services, and multi-paradigm teams implementing modules, components, and services together.

The Law of Demeter restricts how deeply you can chain object calls, forcing you to communicate only with immediate neighbors. This minimizes hidden dependencies, reduces coupling, and makes it easier to refactor or swap implementations without cascading breaks.

Clear boundaries and minimal coupling make testing simpler: each module owns its behavior, dependencies are explicit, and concerns are isolated. Composition and encapsulation let you mock or substitute components without restructuring test setup.