Angular Typescript Interview Question Answers Part 3
Angular Interview Questions – Part 3 (Expert Level)
41. What are Standalone Components in Angular?
Answer: Standalone components do not require NgModules.
Why introduced:
- Less boilerplate
- Simpler architecture
- Faster development
Use case: Modern Angular apps (Angular 14+).
42. What is Server-Side Rendering (SSR) in Angular?
Answer: SSR renders Angular pages on the server instead of browser.
Angular tool: Angular Universal
Benefits:
- Faster first load
- Better SEO
- Improved performance
43. What is Hydration in Angular?
Answer: Hydration connects server-rendered HTML with Angular on the client.
Why important:
- Prevents re-rendering
- Improves performance
44. Template-Driven vs Reactive Forms
Answer:
| Template-Driven | Reactive |
|---|---|
| HTML based | Code based |
| Simple forms | Complex forms |
| Less control | Full control |
| Two-way binding | Immutable data |
Interview tip: Reactive forms are preferred in enterprise apps.
45. What is Form Validation in Angular?
Answer: Angular provides built-in and custom validation.
Examples:
- Required
- MinLength
- Pattern
- Custom validators
Used for: Login, signup, payment forms.
46. What is TrackBy in *ngFor?
Answer:
trackBy improves performance by tracking items by unique id.
Why needed:
- Prevents full DOM re-render
- Faster list updates
47. What is Zone.js?
Answer: Zone.js detects async operations and triggers change detection.
Without Zone.js: Angular wouldn’t know when to update UI.
48. How do you optimize Angular application performance?
Answer: Key techniques:
- Lazy loading
- OnPush change detection
- TrackBy
- AOT compilation
- SSR
- Unsubscribe observables
49. What is Micro Frontend Architecture?
Answer: Micro frontends split frontend into independent apps.
Benefits:
- Independent deployments
- Team scalability
Used in: Large enterprise systems.
50. How does Angular handle Security?
Answer: Angular protects against:
- XSS (automatic sanitization)
- CSRF (HTTP headers)
- Secure DOM handling
Best practices:
- Use HttpClient
- Avoid
innerHTML - Use sanitizers carefully
51. What is Dependency Injection Hierarchy?
Answer: Angular has hierarchical injectors:
- Root injector
- Module injector
- Component injector
Benefit: Efficient memory usage.
52. What is providedIn: 'root'?
Answer: Creates a singleton service available app-wide.
Benefits:
- Tree-shakable
- Cleaner code
53. What is Resolver in Angular?
Answer: Resolver fetches data before route loads.
Use case: Load user profile before opening dashboard.
54. Difference between Subject and BehaviorSubject
Answer:
| Subject | BehaviorSubject |
|---|---|
| No initial value | Requires initial value |
| Emits after subscribe | Emits last value immediately |
55. What is ChangeDetectorRef?
Answer: Allows manual control over change detection.
Used for:
- Performance optimization
- External libraries integration
56. What is Renderer2?
Answer: Safe way to manipulate DOM.
Why used:
- Platform independence
- Security
57. What is ng-template?
Answer: Defines a template that is not rendered immediately.
Used with:
*ngIf*ngFor- Dynamic views
58. What are Angular Schematics?
Answer: Schematics generate code automatically.
Examples:
- Components
- Services
- Modules
59. What is Monorepo in Angular?
Answer: Single repository containing multiple projects.
Tools:
- Nx
- Angular workspace
Benefits:
- Code sharing
- Consistency
60. Real Interview Scenario Question
Question: App is slow when displaying large lists. What will you do?
Answer:
- Use
trackBy - Enable OnPush
- Virtual scrolling
- Lazy loading
- Avoid heavy pipes