Signals in React (III): Lifecycle Never Disappeared

The Lifecycle Never Went Away From the beginning of this series up to the current implementation, everything has revolved around the lifecycle of the data layer : How data is read, invalidated, recomputed, and when side effects are triggered. This does not conflict with the framework’s lifecycle. In fact, React never removed lifecycle — it restructured it into two distinct phases: Render : Purely computes UI. It may run multiple times, be interrupted, or discarded. Ideally, no side effects should occur here. Commit : Applies changes to the DOM in a single, synchronous step. useLayoutEffect / useEffect setup and cleanup run here. This is the only legitimate place for UI side effects. If you’re not familiar with useLayoutEffect and useEffect , review how React manages mount/unmount timing via these hooks. That understanding is foundational. React emphasizes that in typical usage, UI dependencies on state are not explicitly declared . When state updates, React re-runs the component render