The All-in-One Angular Cheat Sheet for Interview 2025

Angular is a powerful and robust front-end framework developed and maintained by Google. Designed for building dynamic and scalable web applications, Angular offers a complete solution for client-side development with tools, libraries, and architecture that suit both small projects and enterprise-level applications. Whether you’re a beginner just getting started or a seasoned developer preparing for technical interviews, this Angular cheat sheet covers essential features, concepts, syntax, and commands you’ll need to boost your productivity and efficiency.

Introduction to Angular

Angular is a TypeScript-based open-source framework used to create single-page applications (SPAs). Its component-based architecture, reactive programming model, and use of RxJS make it ideal for modern web development. With two-way data binding, modularization, and dependency injection, Angular helps streamline the development of dynamic and complex UIs.

Developers frequently look for a consolidated reference to quickly recall commands and concepts — that's where an Angular cheat sheet becomes invaluable.

Angular Project Structure

When you create an Angular application using the CLI, the project structure looks like this:

my-app/
├── e2e/                // End-to-end testing
├── node_modules/
├── src/
│   ├── app/            // Application code
│   ├── assets/         // Static assets
│   ├── environments/   // Environment variables
│   ├── index.html      // Main HTML file
│   ├── main.ts         // Entry point
│   ├── styles.css      // Global styles
├── angular.json        // Angular CLI configuration
├── package.json        // Project dependencies

Understanding this structure is the first step in navigating an Angular project efficiently.

Angular CLI Essentials

The Angular Command Line Interface (CLI) simplifies development by automating repetitive tasks. This section of the Angular CLI commands cheat sheet provides the most commonly used commands:

Project Commands

ng new my-app             # Create a new Angular project
ng serve                  # Start development server
ng build                  # Build the project
ng test                   # Run unit tests
ng lint                   # Lint the project
ng e2e                    # Run end-to-end tests

Generate Commands

ng generate component my-component  # Generate new component
ng g directive my-directive         # Shortcut for directive
ng g service my-service             # Generate a service
ng g module my-module               # Generate a module
ng g pipe my-pipe                   # Generate a pipe
ng g guard my-guard                 # Generate a route guard

These commands are part of the Angular CLI cheat sheet and help you scaffold code efficiently.

Angular Core Concepts

Angular is built around key concepts such as components, templates, services, modules, directives, and pipes.

Components

A component is the building block of Angular applications.

import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'my-app';
}

Templates

Templates define the HTML view of a component. Angular provides built-in directives like *ngIf, *ngFor, and ngClass.

<p *ngIf="isLoggedIn">Welcome!</p>
<ul>
  <li *ngFor="let item of items">{{ item }}</li>
</ul>

Data Binding

Angular supports one-way and two-way data binding.

<!-- One-way binding -->
<h1>{{ title }}</h1>

<!-- Two-way binding -->
<input [(ngModel)]="username">

Understanding data binding is a key part of the Angular syntax cheat sheet.

Dependency Injection and Services

Angular’s built-in dependency injection system allows components to be decoupled from the services they use.

@Injectable({
  providedIn: 'root',
})
export class AuthService {
  isLoggedIn = false;
}

Injecting the service in a component:

constructor(private authService: AuthService) {}

This design principle supports modular, testable, and maintainable code.

Angular Routing and Navigation

Routing in Angular is managed via the @angular/router module. It enables navigation between different components.

Setting up Routes

const routes: Routes = [
  { path: '', component: HomeComponent },
  { path: 'about', component: AboutComponent },
];

Router Module

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }

Navigating Programmatically

this.router.navigate(['/about']);

Routing configuration and lazy loading are commonly asked topics in an Angular interview.

Angular Forms

Angular provides two approaches for handling forms:

Template-driven Forms

<form #form="ngForm" (ngSubmit)="onSubmit(form)">
  <input name="email" ngModel required>
  <button type="submit">Submit</button>
</form>

Reactive Forms

form = new FormGroup({
  email: new FormControl('', [Validators.required, Validators.email])
});

Reactive forms offer more control and are often used in larger applications.

Directives

Angular directives extend the HTML. There are three types:

Structural Directives: *ngIf, *ngFor

Attribute Directives: ngClass, ngStyle

Custom Directives

@Directive({
  selector: '[appHighlight]'
})
export class HighlightDirective {
  constructor(el: ElementRef) {
    el.nativeElement.style.backgroundColor = 'yellow';
  }
}

Pipes

Pipes transform data in templates.

<p>{{ birthday | date }}</p>
<p>{{ amount | currency:'USD' }}</p>

Custom Pipes

@Pipe({ name: 'capitalize' })
export class CapitalizePipe implements PipeTransform {
  transform(value: string): string {
    return value.charAt(0).toUpperCase() + value.slice(1);
  }
}

Lifecycle Hooks

Angular components go through several lifecycle events:

ngOnInit(): void {}
ngOnChanges(): void {}
ngOnDestroy(): void {}

HttpClient for API Requests

To interact with backend services, Angular provides HttpClient.

constructor(private http: HttpClient) {}

getUsers() {
  return this.http.get('https://api.example.com/users');
}

Make sure to import HttpClientModule in the root module.

Deployment

For production:

ng build --configuration=production

Deploy the output in the dist/ folder to hosting services like Firebase, Netlify, or custom servers.

Conclusion

Angular remains a top choice for developing dynamic, maintainable, and scalable web applications. This Angular cheat sheet provides a high-level yet comprehensive overview, serving as a quick reference for development, learning, and interview preparation.

For even deeper understanding, explore the official Angular documentation, contribute to community projects, and stay up to date with the latest updates in Angular’s ecosystem.

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