Angular is a full-featured frontend framework built by Google for creating large, maintainable, and high-performance web applications. Mastering Angular requires understanding both its architecture and core building blocks.
Learn how to build your own software
1. Angular Architecture Overview
Angular follows a component-based architecture and is built around:
- Components
- Modules
- Templates
- Services
- Dependency Injection
- RxJS & Observables
Angular applications are opinionated, meaning the framework enforces structure and best practices.
2. Angular Modules (NgModule)
Modules organize an Angular application into cohesive blocks of functionality.
Types of Modules
- Root Module (
AppModule) - Feature Modules
- Shared Modules
- Core Module
Example
@NgModule({
declarations: [AppComponent],
imports: [BrowserModule],
bootstrap: [AppComponent]
})
export class AppModule {}
Why it matters
- Improves maintainability
- Enables lazy loading
- Encourages separation of concerns
3. Components (The Heart of Angular)
Components control a part of the UI.
A Component Has:
- TypeScript class (logic)
- HTML template (view)
- CSS/SCSS (styling)
@Component({
selector: 'app-header',
templateUrl: './header.component.html'
})
export class HeaderComponent {}
Key ideas
- Reusable UI blocks
- Parent–child communication
- Lifecycle hooks
4. Templates & Data Binding
Angular templates extend HTML with Angular syntax.
Types of Data Binding
Interpolation
<h1>{{ title }}</h1>Property Binding
<img [src]="imageUrl">Event Binding
<button (click)="save()">Save</button>Two-Way Binding
<input [(ngModel)]="username">5. Directives
Directives manipulate the DOM.
Types of Directives
Structural Directives
Change the DOM structure:
*ngIf*ngFor*ngSwitch
<div *ngIf="isLoggedIn">Welcome</div>Attribute Directives
Change appearance or behavior:
ngClassngStyle
6. Services & Dependency Injection (DI)
Services handle business logic, API calls, and shared data.
@Injectable({
providedIn: 'root'
})
export class UserService {
getUsers() {}
}Dependency Injection
Angular automatically provides services to components:
constructor(private userService: UserService) {}Why DI is powerful
- Loose coupling
- Easier testing
- Centralized logic
7. Routing & Navigation
Angular Router enables Single Page Application (SPA) navigation.
Route Configuration
const routes: Routes = [
{ path: 'login', component: LoginComponent }
];Router Features
- Route parameters
- Guards
- Lazy loading
- Child routes
8. Angular Lifecycle Hooks
Lifecycle hooks allow you to run code at specific times.
Common Hooks
ngOnInit()– component initializationngOnChanges()– input changesngOnDestroy()– cleanup
ngOnInit() {
this.loadData();
}9. Forms (Template-Driven & Reactive)
Template-Driven Forms
- Simple
- Uses directives like
ngModel
Reactive Forms (Recommended)
- Scalable
- Explicit form control
this.form = new FormGroup({
email: new FormControl('', Validators.required)
});Reactive forms are best for complex validation and enterprise apps.
10. Observables & RxJS
Angular heavily relies on RxJS for async operations.
this.http.get('/api/users')
.subscribe(data => console.log(data));Key RxJS Concepts
- Observable
- Subscription
- Operators (
map,filter,switchMap) - Subjects
RxJS makes Angular reactive and efficient.
11. HTTP Client & APIs
Angular uses HttpClient for server communication.
this.http.get<User[]>('/api/users');Features
- Interceptors
- Error handling
- Typed responses
12. Change Detection
Angular keeps the UI in sync with data using change detection.
Strategies
- Default
OnPush(performance optimization)
changeDetection: ChangeDetectionStrategy.OnPush13. Pipes
Pipes transform data in templates.
{{ date | date:'short' }}Custom Pipe Example
@Pipe({ name: 'uppercaseText' })
export class UppercasePipe {}14. Guards & Security
Guards control route access.
Common Guards
CanActivateCanDeactivateCanLoad
canActivate(): boolean {
return this.authService.isLoggedIn();
}15. Lazy Loading
Lazy loading improves performance by loading modules only when needed.
{
path: 'admin',
loadChildren: () => import('./admin/admin.module')
.then(m => m.AdminModule)
}16. State Management (Advanced)
For large apps:
- NgRx
- Akita
- Signals (new Angular approach)
Helps manage global state predictably.
17. Angular CLI
The CLI boosts productivity.
ng generate component dashboard
ng build --prod
ng test18. Best Practices You Must Know
- Use feature modules
- Prefer Reactive Forms
- Use
OnPushchange detection - Unsubscribe from observables
- Follow Angular Style Guide
- Keep components “thin”, services “fat”
Final Summary
To truly master Angular, you must understand:
- Components & Modules
- Services & Dependency Injection
- Routing & Forms
- RxJS & Observables
- Performance & architecture best practices
Angular shines in large-scale, enterprise-grade applications where structure, scalability, and maintainability matter.
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