Angular Best Practices | Skills Pool
Angular Best Practices Angular performance optimization and best practices guide. Use when writing, reviewing, or refactoring Angular code for optimal performance, bundle size, and rendering efficiency.
sickn33 33,802 星标 2026年4月13日 Comprehensive performance optimization guide for Angular applications. Contains prioritized rules for eliminating performance bottlenecks, optimizing bundles, and improving rendering.
When to Use
Reference these guidelines when:
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
Rule Categories by Priority
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
快速安装
Angular Best Practices npx skillvault add sickn33/sickn33-antigravity-awesome-skills-plugins-antigravity-awesome-skills-claude-skills-angular-best-practices-skill-md
星标 33,802
更新时间 2026年4月13日
职业 4 Rendering Performance HIGH @defer, trackBy, virtualization
5 Server-Side Rendering HIGH Hydration, prerendering
6 Template Optimization MEDIUM Control flow, pipes
7 State Management MEDIUM Signal patterns, selectors
8 Memory Management LOW-MEDIUM Cleanup, subscriptions
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()],
});
No zone.js patches on async APIs
Smaller bundle (~15KB savings)
Clean stack traces for debugging
Better micro-frontend compatibility
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();
}
}
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';
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" />
}
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)
);
}
5. Server-Side Rendering (HIGH)
// 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);
}
}),
);
}
}
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) { ... }
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
}
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();
}
}
Quick Reference Checklist
New Component
SSR Check
Resources
When to Use This skill is applicable to execute the workflow or actions described in the overview.
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.
02
Rule Categories by Priority
调试
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