Angular Best Practices V2

Angular Best Practices

Overview

This public intake copy packages plugins/antigravity-awesome-skills/skills/angular-best-practices from https://github.com/sickn33/antigravity-awesome-skills into the native Omni Skills editorial shape without hiding its origin.

Use it when the operator needs the upstream workflow, support files, and repository context to stay intact while the public validator and private enhancer continue their normal downstream flow.

This intake keeps the copied upstream files intact and uses the external_source block in metadata.json plus ORIGIN.md as the provenance anchor for review.

Angular Best Practices Comprehensive performance optimization guide for Angular applications. Contains prioritized rules for eliminating performance bottlenecks, optimizing bundles, and improving rendering.

Imported source sections that did not map cleanly to the public headings are still preserved below or in the support files. Notable imported sections: 1. Change Detection (CRITICAL), 2. Async Operations & Waterfalls (CRITICAL), 3. Bundle Optimization (CRITICAL), 4. Rendering Performance (HIGH), 5. Server-Side Rendering (HIGH), 6. Template Optimization (MEDIUM).

When to Use This Skill

Use this section as the trigger filter. It should make the activation boundary explicit before the operator loads files, runs commands, or opens a pull request.

• Writing new Angular components or pages
• Implementing data fetching patterns
• Reviewing code for performance issues
• Refactoring existing Angular code
• Optimizing bundle size or load times
• Configuring SSR/hydration

Operating Table

Workflow

This workflow is intentionally editorial and operational at the same time. It keeps the imported source useful to the operator while still satisfying the public intake standards that feed the downstream enhancer flow.

1. Confirm the user goal, the scope of the imported workflow, and whether this skill is still the right router for the task.
2. Read the overview and provenance files before loading any copied upstream support files.
3. Load only the references, examples, prompts, or scripts that materially change the outcome for the current request.
4. Execute the upstream workflow while keeping provenance and source boundaries explicit in the working notes.
5. Validate the result against the upstream expectations and the evidence you can point to in the copied files.
6. Escalate or hand off to a related skill when the work moves out of this imported workflow's center of gravity.
7. Before merge or closure, record what was used, what changed, and what the reviewer still needs to verify.

Imported Workflow Notes

Imported: 1. Change Detection (CRITICAL)

Use OnPush Change Detection

// CORRECT - OnPush with Signals
@Component({
  changeDetection: ChangeDetectionStrategy.OnPush,
  template: `<div>{{ count() }}</div>`,
})
export class CounterComponent {
  count = signal(0);
}

// WRONG - Default change detection
@Component({
  template: `<div>{{ count }}</div>`, // Checked every cycle
})
export class CounterComponent {
  count = 0;
}

Prefer Signals Over Mutable Properties

// CORRECT - Signals trigger precise updates
@Component({
  template: `
    <h1>{{ title() }}</h1>
    <p>Count: {{ count() }}</p>
  `,
})
export class DashboardComponent {
  title = signal("Dashboard");
  count = signal(0);
}

// WRONG - Mutable properties require zone.js checks
@Component({
  template: `
    <h1>{{ title }}</h1>
    <p>Count: {{ count }}</p>
  `,
})
export class DashboardComponent {
  title = "Dashboard";
  count = 0;
}

Enable Zoneless for New Projects

// main.ts - Zoneless Angular (v20+)
bootstrapApplication(AppComponent, {
  providers: [provideZonelessChangeDetection()],
});

Benefits:

• No zone.js patches on async APIs
• Smaller bundle (~15KB savings)
• Clean stack traces for debugging
• Better micro-frontend compatibility

Examples

Example 1: Ask for the upstream workflow directly

Use @angular-best-practices-v2 to handle <task>. Start from the copied upstream workflow, load only the files that change the outcome, and keep provenance visible in the answer.

Explanation: This is the safest starting point when the operator needs the imported workflow, but not the entire repository.

Example 2: Ask for a provenance-grounded review

Review @angular-best-practices-v2 against metadata.json and ORIGIN.md, then explain which copied upstream files you would load first and why.

Explanation: Use this before review or troubleshooting when you need a precise, auditable explanation of origin and file selection.

Example 3: Narrow the copied support files before execution

Use @angular-best-practices-v2 for <task>. Load only the copied references, examples, or scripts that change the outcome, and name the files explicitly before proceeding.

Explanation: This keeps the skill aligned with progressive disclosure instead of loading the whole copied package by default.

Example 4: Build a reviewer packet

Review @angular-best-practices-v2 using the copied upstream files plus provenance, then summarize any gaps before merge.

Explanation: This is useful when the PR is waiting for human review and you want a repeatable audit packet.

Best Practices

Treat the generated public skill as a reviewable packaging layer around the upstream repository. The goal is to keep provenance explicit and load only the copied source material that materially improves execution.

• Priority - Category - Impact - Focus
• 1 - Change Detection - CRITICAL - Signals, OnPush, Zoneless
• 2 - Async Waterfalls - CRITICAL - RxJS patterns, SSR preloading
• 3 - Bundle Optimization - CRITICAL - Lazy loading, tree shaking
• 4 - Rendering Performance - HIGH - @defer, trackBy, virtualization
• 5 - Server-Side Rendering - HIGH - Hydration, prerendering
• 6 - Template Optimization - MEDIUM - Control flow, pipes

Imported Operating Notes

Imported: Rule Categories by Priority

Troubleshooting

Problem: The operator skipped the imported context and answered too generically

Symptoms: The result ignores the upstream workflow in plugins/antigravity-awesome-skills/skills/angular-best-practices, fails to mention provenance, or does not use any copied source files at all. Solution: Re-open metadata.json, ORIGIN.md, and the most relevant copied upstream files. Check the external_source block first, then restate the provenance before continuing.

Problem: The imported workflow feels incomplete during review

Symptoms: Reviewers can see the generated SKILL.md, but they cannot quickly tell which references, examples, or scripts matter for the current task. Solution: Point at the exact copied references, examples, scripts, or assets that justify the path you took. If the gap is still real, record it in the PR instead of hiding it.

Problem: The task drifted into a different specialization

Symptoms: The imported skill starts in the right place, but the work turns into debugging, architecture, design, security, or release orchestration that a native skill handles better. Solution: Use the related skills section to hand off deliberately. Keep the imported provenance visible so the next skill inherits the right context instead of starting blind.

Related Skills

• @20-andruia-niche-intelligence-v2 - Use when the work is better handled by that native specialization after this imported skill establishes context.
• @advogado-criminal-v2 - Use when the work is better handled by that native specialization after this imported skill establishes context.
• @advogado-especialista-v2 - Use when the work is better handled by that native specialization after this imported skill establishes context.
• @agent-memory-systems-v2 - Use when the work is better handled by that native specialization after this imported skill establishes context.

Additional Resources

Use this support matrix and the linked files below as the operator packet for this imported skill. They should reflect real copied source material, not generic scaffolding.

• README.md

Imported Reference Notes

Imported: Quick Reference Checklist

New Component

• changeDetection: ChangeDetectionStrategy.OnPush
• standalone: true
• Signals for state (signal(), input(), output())
• inject() for dependencies
• @for with track expression

Performance Review

• No methods in templates (use pipes or computed)
• Large lists virtualized
• Heavy components deferred
• Routes lazy-loaded
• Third-party libs dynamically imported

SSR Check

• Hydration configured
• Critical content renders first
• Non-critical content uses @defer (hydrate on ...)
• TransferState for server-fetched data

Imported: Resources

• Angular Performance Guide
• Zoneless Angular
• Angular SSR Guide
• Change Detection Deep Dive

Imported: 2. Async Operations & Waterfalls (CRITICAL)

Eliminate Sequential Data Fetching

// WRONG - Nested subscriptions create waterfalls
this.route.params.subscribe((params) => {
  // 1. Wait for params
  this.userService.getUser(params.id).subscribe((user) => {
    // 2. Wait for user
    this.postsService.getPosts(user.id).subscribe((posts) => {
      // 3. Wait for posts
    });
  });
});

// CORRECT - Parallel execution with forkJoin
forkJoin({
  user: this.userService.getUser(id),
  posts: this.postsService.getPosts(id),
}).subscribe((data) => {
  // Fetched in parallel
});

// CORRECT - Flatten dependent calls with switchMap
this.route.params
  .pipe(
    map((p) => p.id),
    switchMap((id) => this.userService.getUser(id)),
  )
  .subscribe();

Avoid Client-Side Waterfalls in SSR

// CORRECT - Use resolvers or blocking hydration for critical data
export const route: Route = {
  path: "profile/:id",
  resolve: { data: profileResolver }, // Fetched on server before navigation
  component: ProfileComponent,
};

// WRONG - Component fetches data on init
class ProfileComponent implements OnInit {
  ngOnInit() {
    // Starts ONLY after JS loads and component renders
    this.http.get("/api/profile").subscribe();
  }
}

Imported: 3. Bundle Optimization (CRITICAL)

Lazy Load Routes

// CORRECT - Lazy load feature routes
export const routes: Routes = [
  {
    path: "admin",
    loadChildren: () =>
      import("./admin/admin.routes").then((m) => m.ADMIN_ROUTES),
  },
  {
    path: "dashboard",
    loadComponent: () =>
      import("./dashboard/dashboard.component").then(
        (m) => m.DashboardComponent,
      ),
  },
];

// WRONG - Eager loading everything
import { AdminModule } from "./admin/admin.module";
export const routes: Routes = [
  { path: "admin", component: AdminComponent }, // In main bundle
];

Use @defer for Heavy Components

<!-- CORRECT - Heavy component loads on demand -->
@defer (on viewport) {
<app-analytics-chart [data]="data()" />
} @placeholder {
<div class="chart-skeleton"></div>
}

<!-- WRONG - Heavy component in initial bundle -->
<app-analytics-chart [data]="data()" />

Avoid Barrel File Re-exports

// WRONG - Imports entire barrel, breaks tree-shaking
import { Button, Modal, Table } from "@shared/components";

// CORRECT - Direct imports
import { Button } from "@shared/components/button/button.component";
import { Modal } from "@shared/components/modal/modal.component";

Dynamic Import Third-Party Libraries

// CORRECT - Load heavy library on demand
async loadChart() {
  const { Chart } = await import('chart.js');
  this.chart = new Chart(this.canvas, config);
}

// WRONG - Bundle Chart.js in main chunk
import { Chart } from 'chart.js';

Imported: 4. Rendering Performance (HIGH)

Always Use trackBy with @for

<!-- CORRECT - Efficient DOM updates -->
@for (item of items(); track item.id) {
<app-item-card [item]="item" />
}

<!-- WRONG - Entire list re-renders on any change -->
@for (item of items(); track $index) {
<app-item-card [item]="item" />
}

Use Virtual Scrolling for Large Lists

import { CdkVirtualScrollViewport, CdkFixedSizeVirtualScroll } from '@angular/cdk/scrolling';

@Component({
  imports: [CdkVirtualScrollViewport, CdkFixedSizeVirtualScroll],
  template: `
    <cdk-virtual-scroll-viewport itemSize="50" class="viewport">
      <div *cdkVirtualFor="let item of items" class="item">
        {{ item.name }}
      </div>
    </cdk-virtual-scroll-viewport>
  `
})

Prefer Pure Pipes Over Methods

// CORRECT - Pure pipe, memoized
@Pipe({ name: 'filterActive', standalone: true, pure: true })
export class FilterActivePipe implements PipeTransform {
  transform(items: Item[]): Item[] {
    return items.filter(i => i.active);
  }
}

// Template
@for (item of items() | filterActive; track item.id) { ... }

// WRONG - Method called every change detection
@for (item of getActiveItems(); track item.id) { ... }

Use computed() for Derived Data

// CORRECT - Computed, cached until dependencies change
export class ProductStore {
  products = signal<Product[]>([]);
  filter = signal('');

  filteredProducts = computed(() => {
    const f = this.filter().toLowerCase();
    return this.products().filter(p =>
      p.name.toLowerCase().includes(f)
    );
  });
}

// WRONG - Recalculates every access
get filteredProducts() {
  return this.products.filter(p =>
    p.name.toLowerCase().includes(this.filter)
  );
}

Imported: 5. Server-Side Rendering (HIGH)

Configure Incremental Hydration

// app.config.ts
import {
  provideClientHydration,
  withIncrementalHydration,
} from "@angular/platform-browser";

export const appConfig: ApplicationConfig = {
  providers: [
    provideClientHydration(withIncrementalHydration(), withEventReplay()),
  ],
};

Defer Non-Critical Content

<!-- Critical above-the-fold content -->
<app-header />
<app-hero />

<!-- Below-fold deferred with hydration triggers -->
@defer (hydrate on viewport) {
<app-product-grid />
} @defer (hydrate on interaction) {
<app-chat-widget />
}

Use TransferState for SSR Data

@Injectable({ providedIn: "root" })
export class DataService {
  private http = inject(HttpClient);
  private transferState = inject(TransferState);
  private platformId = inject(PLATFORM_ID);

  getData(key: string): Observable<Data> {
    const stateKey = makeStateKey<Data>(key);

    if (isPlatformBrowser(this.platformId)) {
      const cached = this.transferState.get(stateKey, null);
      if (cached) {
        this.transferState.remove(stateKey);
        return of(cached);
      }
    }

    return this.http.get<Data>(`/api/${key}`).pipe(
      tap((data) => {
        if (isPlatformServer(this.platformId)) {
          this.transferState.set(stateKey, data);
        }
      }),
    );
  }
}

Imported: 6. Template Optimization (MEDIUM)

Use New Control Flow Syntax

<!-- CORRECT - New control flow (faster, smaller bundle) -->
@if (user()) {
<span>{{ user()!.name }}</span>
} @else {
<span>Guest</span>
} @for (item of items(); track item.id) {
<app-item [item]="item" />
} @empty {
<p>No items</p>
}

<!-- WRONG - Legacy structural directives -->
<span *ngIf="user; else guest">{{ user.name }}</span>
<ng-template #guest><span>Guest</span></ng-template>

Avoid Complex Template Expressions

// CORRECT - Precompute in component
class Component {
  items = signal<Item[]>([]);
  sortedItems = computed(() =>
    [...this.items()].sort((a, b) => a.name.localeCompare(b.name))
  );
}

// Template
@for (item of sortedItems(); track item.id) { ... }

// WRONG - Sorting in template every render
@for (item of items() | sort:'name'; track item.id) { ... }

Imported: 7. State Management (MEDIUM)

Use Selectors to Prevent Re-renders

// CORRECT - Selective subscription
@Component({
  template: `<span>{{ userName() }}</span>`,
})
class HeaderComponent {
  private store = inject(Store);
  // Only re-renders when userName changes
  userName = this.store.selectSignal(selectUserName);
}

// WRONG - Subscribing to entire state
@Component({
  template: `<span>{{ state().user.name }}</span>`,
})
class HeaderComponent {
  private store = inject(Store);
  // Re-renders on ANY state change
  state = toSignal(this.store);
}

Colocate State with Features

// CORRECT - Feature-scoped store
@Injectable() // NOT providedIn: 'root'
export class ProductStore { ... }

@Component({
  providers: [ProductStore], // Scoped to component tree
})
export class ProductPageComponent {
  store = inject(ProductStore);
}

// WRONG - Everything in global store
@Injectable({ providedIn: 'root' })
export class GlobalStore {
  // Contains ALL app state - hard to tree-shake
}

Imported: 8. Memory Management (LOW-MEDIUM)

Use takeUntilDestroyed for Subscriptions

import { takeUntilDestroyed } from '@angular/core/rxjs-interop';

@Component({...})
export class DataComponent {
  private destroyRef = inject(DestroyRef);

  constructor() {
    this.data$.pipe(
      takeUntilDestroyed(this.destroyRef)
    ).subscribe(data => this.process(data));
  }
}

// WRONG - Manual subscription management
export class DataComponent implements OnDestroy {
  private subscription!: Subscription;

  ngOnInit() {
    this.subscription = this.data$.subscribe(...);
  }

  ngOnDestroy() {
    this.subscription.unsubscribe(); // Easy to forget
  }
}

Prefer Signals Over Subscriptions

// CORRECT - No subscription needed
@Component({
  template: `<div>{{ data().name }}</div>`,
})
export class Component {
  data = toSignal(this.service.data$, { initialValue: null });
}

// WRONG - Manual subscription
@Component({
  template: `<div>{{ data?.name }}</div>`,
})
export class Component implements OnInit, OnDestroy {
  data: Data | null = null;
  private sub!: Subscription;

  ngOnInit() {
    this.sub = this.service.data$.subscribe((d) => (this.data = d));
  }

  ngOnDestroy() {
    this.sub.unsubscribe();
  }
}

Imported: Limitations

• Use this skill only when the task clearly matches the scope described above.
• Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
• Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.