3 Effective Rules for Using Signals in Angular

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AngularArchitects.io | @ManfredSteyer | @RainerHahnekamp 3 Effective Rules for Using Signals in Angular

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Agenda • Austrian Desserts • Computed • Resource API • Effects • Stores

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Result 3 Rules (of thumb)

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About me… Manfred Steyer, ANGULARarchitects.io (Remote) Angular Workshops and Consulting Google Developer Expert for Angular Blog, Books, Articles, and Talks about Angular Manfred Steyer

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Austrian Desserts: Example App

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Demo

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Computed: Extremely Unterrated!

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Reactive Programming: Paradigm Shift!

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Marble Run

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Marble Run Data Binding

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Reactive Flow with Computed desserts = signal([]); ratings = signal({}); ratedDesserts = computed(() => this.toRated(this.desserts(), this.ratings()));

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Reactive Flow with Computed desserts = signal([]); ratings = signal({}); ratedDesserts = computed(() => this.toRated(this.desserts(), this.ratings()));

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Demo Branch: 02a-input-signals

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Reactive Flow with Computed desserts = signal([]); ratings = signal({}); ratedDesserts = computed(() => this.toRated(this.desserts(), this.ratings())); originalName = signal(''); englishName = signal(''); Load Desserts

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Resource API

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Resource API dessertsResource = resource({ request: this.dessertsCriteria, loader: (param) => { return this.#dessertService.findPromise(param.request); } }); Experimental in Angular 19

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Resource API dessertsResource = resource({ request: this.dessertsCriteria, loader: (param) => { return this.#dessertService.findPromise(param.request); } }); dessertsCriteria = computed(() => ({ originalName: this.originalName(), englishName: this.englishName(), })); desserts = this.dessertsResource.value; ratedDesserts = computed(() => this.toRated(this.desserts, …));

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Resource Prevents Race Conditions Pancakes Sacher Cake Ice Cream Pancakes

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Resource Prevents Race Conditions Pancakes Sacher Cake Ice Cream Pancakes „switchMap semantics“

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Demo Branch: 2c-resource

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Architecture Rule #1 Derive state where possible

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Effects

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Connecting Reactive and Imperative World

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Ideal-typical Tasks • Drawing on a canvas • Manual DOM manipulations • Logging • Synching with LocalStore Stuff, you cannot do with data binding Rendering (and similar tasks …)

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Demo Branch: 04c-effects

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Architecture Rule #2 Avoid effects triggering business logic

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Instead: Reactive Helpers like Resource API @ngrx/signals ngxtension Your Own …

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Reactive Helpers: Effects Under the Hood

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Demo Branch: 08b-details

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Stores

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Stores Streamline Reactive Flow Component Store "Intention" Signal sync/ async computed() computed()

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Demo Branch: 08b-details

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Architecture Rule #3 Stores make your reactive flow more manageable

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Free eBook (6th Edition) angularArchitects.io/ebook

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Conclusion Architecture Rule #1 Derive state where possible Architecture Rule #2 Avoid effects triggering business logic Architecture Rule #3 Stores make your reactive flow more manageable