Angular Tutorial Chapter 6: Distinguishing Null, Reset, and Destroy in Feature Lifecycle

An Angular tutorial chapter explains that clearing data and ending a feature are fundamentally different operations, each requiring a distinct API call. The chapter introduces three operations — replaceState(null), reset(), and destroy() — to make lifecycle intent explicit rather than inferred from empty UI state. replaceState(null) commits an intentional null while keeping the feature active, reset() returns the runtime to a neutral reusable state, and destroy() permanently finalizes the feature instance. The tutorial enforces a strict ownership boundary where the service controls all lifecycle operations and the FeatureCell, while the component handles only temporary UI state. This design prevents ambiguity in scenarios like user sign-out, account switching, or screen teardown, which can all appear identical on screen but carry different lifecycle meanings.