Angular Core

Standalone Components (REQUIRED)

Components are standalone by default. Do NOT set standalone: true.

@Component({
  selector: 'app-user',
  imports: [CommonModule],
  changeDetection: ChangeDetectionStrategy.OnPush,
  template: `...`
})
export class UserComponent {}

---

Input/Output Functions (REQUIRED)

// ✅ ALWAYS: Function-based
readonly user = input.required<User>();
readonly disabled = input(false);
readonly selected = output<User>();
readonly checked = model(false);  // Two-way binding

// ❌ NEVER: Decorators
@Input() user: User;
@Output() selected = new EventEmitter<User>();

---

Signals for State (REQUIRED)

readonly count = signal(0);
readonly doubled = computed(() => this.count() * 2);

// Update
this.count.set(5);
this.count.update(prev => prev + 1);

// Side effects
effect(() => localStorage.setItem('count', this.count().toString()));

---

NO Lifecycle Hooks (REQUIRED)

Signals replace lifecycle hooks. Do NOT use ngOnInit, ngOnChanges, ngOnDestroy.

// ❌ NEVER: Lifecycle hooks
ngOnInit() {
  this.loadUser();
}