Angular Concepts (Basics to Advanced)

1. Angular Fundamentals

• TypeScript: Primary language for Angular apps, superset of JavaScript.
• Components: Building blocks of the UI, defined with @Component.
• Templates: HTML views linked to components with data binding.
• Modules (NgModule): Grouping of components, directives, pipes, and services.
• Directives: Instructions in the DOM.
  • Structural directives (e.g., *ngIf, *ngFor)
  • Attribute directives (e.g., ngClass, ngStyle)
• Pipes: Transform displayed values in templates (e.g., date, currency, custom pipes).
• Data Binding:
  • Interpolation ({{ value }})
  • Property binding ([ ] syntax)
  • Event binding (( ) syntax)
  • Two-way binding [(ngModel)]

2. Dependency Injection (DI)

• Services: Classes that provide shared functionality (e.g., data fetching, logging).
• Injectors: Responsible for creating and delivering service instances.
• Providers: Configuration that tells Angular how to create a service.
• Hierarchical DI: Services can be scoped at root, module, or component level.

3. Angular Forms

• Template-driven forms: Simple, uses directives like ngModel.
• Reactive forms: More powerful, uses FormControl, FormGroup, and FormBuilder.
• Validation: Built-in validators, custom validators, async validators.

4. Angular Routing

• RouterModule: Configures routes for navigation.
• Route Parameters: Pass dynamic values in URLs.
• Guards:
  • CanActivate, CanDeactivate, Resolve, CanLoad.
• Lazy Loading: Load feature modules on demand.

5. Angular State Management

• Component state: Local state within components.
• Service-based state: Shared state using services.
• NgRx: Redux-inspired state management library.
• Signals (Angular 16+): Fine-grained reactivity system replacing heavy change detection.

6. Change Detection

• Default Strategy: Angular checks the entire component tree.
• OnPush Strategy: Optimized, only re-checks when inputs change or signals emit.
• Zone.js: Tracks async tasks and triggers change detection (being phased out in favor of signals).

7. Advanced Angular Concepts

• Lifecycle Hooks: ngOnInit, ngOnChanges, ngAfterViewInit, etc.
• Standalone Components (Angular 15+): Components without NgModules.
• Control Flow Syntax (Angular 17+): @if, @for, @switch for templates.
• Deferrable Views: @defer syntax for lazy rendering in templates.
• SSR & Hydration: Server-side rendering with Angular Universal and hydration (v16+).
• Micro-frontends: Module federation for large apps.

8. Angular Build & Tooling

• Angular CLI: Scaffolding, building, serving, testing.
• Vite/esbuild (Angular 17): Faster build and dev server integration.
• AOT vs JIT: Compilation strategies (AOT is default for production).
• Tree Shaking: Remove unused code for smaller bundles.

9. Testing in Angular

• Unit Testing: Jasmine, Karma for components and services.
• Integration Testing: TestBed utility.
• End-to-End Testing: Protractor (deprecated), Cypress, Playwright.

10. Angular and Web APIs

• HTTPClientModule: REST API communication with Observables.
• Interceptors: Modify requests and responses (e.g., add auth headers).
• Web Components: Angular components as custom elements.
• PWA: Service workers, caching, offline support, push notifications.

11. Security

• Sanitization: Prevent XSS by cleaning untrusted HTML.
• Route Guards: Control access to routes.
• Authentication & Authorization: JWT, OAuth integration.
• Content Security Policy (CSP): Best practices for Angular apps.

12. Internationalization (i18n)

• i18n tools: Angular built-in localization features.
• ngx-translate: Popular third-party translation library.

13. Performance Optimization

• Lazy loading modules and components.
• Preloading strategies.
• Change detection optimizations (OnPush, signals).
• TrackBy in *ngFor to reduce re-renders.
• Async pipes for efficient Observables handling.

14. Future Directions

• Signals as the foundation of Angular reactivity.
• Zone.js optional (signal-first architecture).
• Better integration with Web APIs and modern JavaScript features.
• Improved developer tooling (Vite, esbuild, faster builds).

Summary

Angular is a complete framework covering everything from components, routing, and forms to advanced reactivity, SSR, state management, and build tooling. Modern Angular (16–17) introduces signals, declarative control flow, deferrable views, and Vite-based builds, pushing Angular toward a faster, more ergonomic, and future-ready ecosystem.