Angular Typescript Interview Question Answers Part 6
Angular Interview Questions – Part 6 (System Design, Performance & Decision-Making)
101. How do you design an Angular application from scratch?
Answer (structured approach):
- Identify features & domains
- Create feature-based folder structure
- Decide routing & lazy loading strategy
- Choose state management
- Define shared & core layers
- Set performance + security standards
Interview keyword: Scalability-first design
102. How do you decide between NgRx, Signals, or Services?
Answer:
| Scenario | Best Choice |
|---|---|
| Simple local state | Signals |
| Shared app-wide state | Services + RxJS |
| Large complex state | NgRx |
Strong answer: “Use the simplest solution that meets complexity.”
103. How do you debug performance issues in Angular?
Answer:
- Chrome DevTools (Performance tab)
- Angular DevTools
- Check change detection cycles
- Identify heavy components
- Analyze bundle size
104. What causes excessive change detection?
Answer:
- Default change detection everywhere
- Inline functions in templates
- Mutable objects
- Unnecessary subscriptions
Fix:
OnPush, immutability, signals.
105. How do you handle large tables (10k+ rows)?
Answer:
- Virtual scrolling
- Pagination
- TrackBy
- OnPush strategy
- Avoid heavy pipes
106. How do you design reusable Angular components?
Answer:
- Input/Output based API
- Content projection
- No business logic inside
- Config-driven behavior
Example: Button, modal, table, dropdown.
107. Smart vs Dumb Components
Answer:
| Smart | Dumb |
|---|---|
| Business logic | UI only |
| API calls | Inputs/Outputs |
| State handling | Stateless |
Why interviewers love this: Shows clean architecture thinking.
108. How do you manage cross-component communication?
Answer:
- Parent → Child:
@Input - Child → Parent:
@Output - Siblings: Shared service
- Global: State management
109. How do you prevent memory leaks in real projects?
Answer:
- Async pipe
- takeUntil pattern
- ngOnDestroy cleanup
- Avoid manual subscriptions
110. How do you handle real-time data in Angular?
Answer:
- WebSockets
- RxJS streams
- Signal-based state
- OnPush change detection
Use case: Chat apps, live dashboards.
111. How do you handle SSR caching?
Answer:
- Cache server-rendered pages
- Use CDN
- Avoid user-specific data on server
Result: Faster TTFB + SEO boost.
112. How do you design Angular apps for SEO?
Answer:
- SSR (Angular Universal)
- Meta service
- Pre-rendering
- Clean URLs
113. How do you handle breaking Angular upgrades?
Answer:
- Incremental upgrades
- Feature flags
- Strong test coverage
- Avoid deprecated APIs
114. How do you integrate Angular with legacy systems?
Answer:
- Micro frontends
- iFrame (last option)
- API contracts
- Gradual migration
115. How do you enforce coding standards?
Answer:
- ESLint
- Prettier
- Code reviews
- CI pipelines
116. How do you measure Angular app success?
Answer:
- Performance metrics
- Error rate
- User engagement
- Bundle size trends
117. How do you mentor junior Angular developers?
Answer:
- Enforce best practices
- Code reviews with explanations
- Encourage architectural thinking
- Avoid overengineering
(This question appears in lead roles a lot.)
118. Design Question (Very Common)
Question: Design a dashboard with 50 widgets.
Answer approach:
- Lazy load widgets
- Dynamic component loading
- Signals for local state
- Shared service for config
- Virtual scrolling
119. Architecture Red Flag Question
Question: When would you NOT use Angular?
Answer:
- Very small static sites
- Simple landing pages
- When bundle size is critical
(Honest answers score points.)
120. Ultimate Interview Question 🧠
Question: What makes a great Angular engineer?
Answer:
- Understands why, not just how
- Balances performance & simplicity
- Writes maintainable code
- Thinks in systems, not components