# Spot the bug: Angular

> One snippet. Find the bug, or prove there isn't one.

Daily challenge: 2026-08-19 (UTC) · Mid-Level

```typescript
import { Injectable, Component } from '@angular/core';
import { BehaviorSubject } from 'rxjs';

@Injectable({ providedIn: 'root' })
export class CartService {
  private itemsSubject = new BehaviorSubject<string[]>([]);
  items$ = this.itemsSubject.asObservable();

  add(item: string) {
    this.itemsSubject.next([...this.itemsSubject.value, item]);
  }
}

@Component({
  selector: 'app-cart-badge',
  template: `<span>{{ (items$ | async)?.length }}</span>`,
  providers: [CartService],
})
export class CartBadgeComponent {
  items$ = this.cart.items$;
  constructor(private cart: CartService) {}
}
```

## Your verdict

- Security flaw
- Logic bug
- Code style
- No issue

One attempt per day. The answer shows up right after.

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