RainerHahnekamp Game Changer: NgRx Signal Store Rainer Hahnekamp - 29. February 2024 - ngOslo

RainerHahnekamp About Me... Professional NgRx https://www.youtube.com/ @RainerHahnekamp https://www.ng-news.com https://github.com/softarc-consulting/sheriff ● Rainer Hahnekamp ANGULARarchitects.io ● Developer / Trainer / Speaker Modern Spring for Angular @RainerHahnekamp

RainerHahnekamp signalStore withState withMethods withComputed Signal withHooks Slices aka. DeepSignal patchState rxMethod

RainerHahnekamp In a Nutshell ● Light-weight state management on top of Signals ● Logic and State in one Place

RainerHahnekamp withState({someState}) ● Contains the State internally as a Signal ● Exposes Signal Slices ● Allows easy updates via patchState

RainerHahnekamp signalStore & withState({someState}) export const QuizStore = signalStore( withState({ title: '', questions: [] as Question[], timeInSeconds: 180 }) )

RainerHahnekamp withMethods(() => {methods}) ● Adds public methods to the Store ● Binds Data (State) and Logic (Methods) together ● Provides Access to DI

RainerHahnekamp withMethods(() => {methods}) withMethods((store) => { const quizService = inject(QuizService); return { answer(questionId: number, choiceId: number) { const question = store .questions() .find((question) => question.id === questionId); assertDefined(question); patchState(store, (quiz) => ({ // ... })); } })

RainerHahnekamp withComputed(() => {computeds}) ● Adds derived Signals ● Collection of multiple computed() in one place

RainerHahnekamp withComputed(() => {computeds}) withComputed((state) => { return { status: computed(() => { const status: Record = { unanswered: 0, correct: 0, incorrect: 0, }; for (const question of state.questions()) { status[question.status]++; } return status; }), }; })

RainerHahnekamp rxMethod: Integrating RxJs withMethods((store) => { const quizService = inject(QuizService); return { setId: rxMethod( pipe( switchMap((id) => quizService.findById(id)), tap((quiz) => patchState(store, quiz)), ), ), }))

RainerHahnekamp Architectural Consequences ● State Management becomes ○ Less boilerplate ○ Extends Signal ● More Local than Global State Management ● Data Module Type contains only API Services ○ fetch/HttpClient-based Services ○ OpenAPI

RainerHahnekamp Summary ● Embraces (builds upon) Angular's Signal ○ Reactivity ○ Computed ○ Immutability ● Extends the Signal ○ patchState ○ Slices ● Adds support for asynchronous + Signals ● Optionally integrates RxJs ● Brings Logic and Data in a structured way together ● Highly Extensible ● Provides Local and Global State

RainerHahnekamp Introducing NgRx Toolkit @angular-architects/ngrx-toolkit Redux DevTools Encapsulation Entities Extensions with API @ ngrx/data

RainerHahnekamp Further Reading and Watching https://youtu.be/TLq0OcSshYI https://youtu.be/V-D2sk_azcs

RainerHahnekamp Further Reading and Watching ● https://ngrx.io/guide/signals ● https://medium.com/ngconf/ngrx-signal-store-the-missing-piece-to-signal s-ac125d804026 ● https://www.angulararchitects.io/en/blog/the-new-ngrx-signal-store-for-a ngular-2-1-flavors ● https://www.youtube.com/watch?v=yaOLbKwVRtc