angular-state-management

Use Signal services for small apps with simple shared state, ComponentStore for medium apps with component-level state, and NgRx Store for large apps with complex cross-feature dependencies. The decision depends on state scope, complexity, and whether you need devtools and action tracing.

Replace BehaviorSubject with a private writable signal and expose it publicly with asReadonly(). Change calls from subject.next(value) to signal.set(value) or signal.update(), and convert derived observables to computed() signals.

NgRx SignalStore is a signal-based state solution built with signalStore, withState, withComputed, and withMethods. Use it for feature-scoped state that needs computed values and methods without the boilerplate of full NgRx actions, reducers, and effects.

Yes, use toSignal() from @angular/core/rxjs-interop to convert observables like route params into signals, and toObservable() to convert signals back into observables for operators like debounceTime and switchMap.

Update the signal state immediately before the HTTP request, then roll back to the previous state in the catch block if the request fails. Store the prior data snapshot before mutating so it can be restored on error.

Avoid NgRx Store for small apps or simple shared UI state like theme and preferences, where a lightweight Signal service is sufficient. NgRx adds boilerplate that only pays off with complex cross-feature state flows.