13 Angular Concepts You Must Master Before Your Next Interview (2026 Edition)

13 Angular Concepts You Must Master Before Your Next Interview (2026 Edition) TL;DR — If you can explain these 13 ideas from code , you won’t “pass the interview.” You’ll set the bar . This isn’t a “tips & tricks” post. It’s a code-first mental model for senior Angular interviews in 2026: short statements, sharp trade-offs, minimal but correct snippets, and measurable performance instincts. Quick roadmap (print this) 1) Change detection & OnPush 2) Observables: cancellation + core RxJS operators 3) DI hierarchies: provider scope + tree-shakable providers 4) Lazy loading + targeted preloading 5) Router guards, resolvers, and route composition 6) Reactive forms with performance in mind 7) NgZone + running work outside Angular 8) trackBy , pure pipes, and memoization for lists 9) Build targets: AOT, prod flags, bundle analysis 10) State patterns: local vs global + Signals (or stores) 11) Testing: TestBed, shallow tests, spies 12) Security: XSS, CSP, sanitizer usage 13) Performance profili