Angular Interview Questions

Posted on: January 19, 2025 Posted by: rahulgite Comments: 0

Below is a comprehensive list of 200 Angular interview questions categorized by topics to help you prepare for interviews. Each question is designed to test various aspects of Angular concepts and implementation.

1. Basic Angular Concepts

  1. What is Angular, and how is it different from AngularJS?
  2. Explain the architecture of Angular.
  3. What are the main features of Angular?
  4. What is a component in Angular?
  5. What is a module in Angular?
  6. How do you create a new Angular project?
  7. What is the role of the main.ts file in Angular?
  8. What is Angular CLI, and how do you use it?
  9. Explain the purpose of the @NgModule decorator.
  10. What are directives in Angular? Name the types of directives.

2. Angular Components and Templates

  1. How do you create a component in Angular?
  2. What is the purpose of the @Component decorator?
  3. What is data binding in Angular? Explain its types.
  4. What is interpolation, and how is it used?
  5. What is the difference between property binding and attribute binding?
  6. Explain two-way data binding in Angular.
  7. How do you define and use a template reference variable in Angular?
  8. What is the difference between inline and external templates?
  9. How do you use the ng-content directive?
  10. What is the role of lifecycle hooks in Angular?

3. Angular Services and Dependency Injection

  1. What is a service in Angular?
  2. How do you create and inject a service in a component?
  3. What is dependency injection, and how does Angular implement it?
  4. What is the role of the @Injectable decorator?
  5. What is the difference between providedIn: 'root' and adding a service in a module’s providers array?
  6. How do you use hierarchical injectors in Angular?
  7. What are tokens in Angular dependency injection?
  8. Explain the difference between a singleton service and a non-singleton service.
  9. How do you inject a service into another service?
  10. What are multi-providers in Angular?

4. Angular Directives

  1. What are structural directives in Angular?
  2. How do you use the *ngIf directive?
  3. What is the purpose of the *ngFor directive?
  4. How do you use the *ngSwitch directive in Angular?
  5. What are attribute directives?
  6. How do you create a custom directive in Angular?
  7. What is the difference between structural and attribute directives?
  8. How do you apply multiple directives to the same element?
  9. What is the role of the Renderer2 service in Angular directives?
  10. Explain how ElementRef is used in custom directives.

5. Angular Routing and Navigation

  1. What is routing in Angular?
  2. How do you configure routes in Angular?
  3. What is the purpose of the RouterModule?
  4. How do you navigate between routes programmatically?
  5. What is a route guard, and how do you implement it?
  6. Explain the difference between canActivate and canDeactivate guards.
  7. How do you pass parameters to routes in Angular?
  8. What is the difference between query parameters and route parameters?
  9. How do you use child routes in Angular?
  10. What is lazy loading, and how do you implement it?

6. Forms in Angular

  1. What is the difference between template-driven and reactive forms?
  2. How do you create a template-driven form in Angular?
  3. How do you use form validation in template-driven forms?
  4. What are reactive forms in Angular?
  5. How do you create a reactive form using FormBuilder?
  6. What is the purpose of FormGroup and FormControl?
  7. How do you validate reactive forms in Angular?
  8. What are custom validators in Angular forms?
  9. How do you handle dynamic forms in Angular?
  10. Explain the role of ngModel in template-driven forms.

7. Angular Pipes

  1. What are pipes in Angular?
  2. How do you use a built-in pipe in Angular?
  3. What is the difference between pure and impure pipes?
  4. How do you create a custom pipe in Angular?
  5. What is the async pipe, and how is it used?
  6. Explain how chaining multiple pipes works.
  7. How do you use parameters in custom pipes?
  8. What are the limitations of Angular pipes?
  9. How do pipes work with observables?
  10. Explain the role of pipes in internationalization.

8. Angular Observables and RxJS

  1. What are observables in Angular?
  2. How do you create and subscribe to an observable?
  3. What is the difference between observables and promises?
  4. What is RxJS, and why is it used in Angular?
  5. What are operators in RxJS?
  6. Explain the difference between map, mergeMap, switchMap, and concatMap.
  7. What is the role of subjects in RxJS?
  8. How do you handle errors in observables?
  9. What is the purpose of take and takeUntil operators?
  10. How do you unsubscribe from observables?

9. Testing in Angular

  1. What is unit testing in Angular?
  2. How do you write a unit test for a component?
  3. What is the purpose of TestBed in Angular testing?
  4. How do you mock dependencies in Angular tests?
  5. What is end-to-end (E2E) testing in Angular?
  6. What is Protractor, and how is it used in Angular testing?
  7. How do you test services in Angular?
  8. How do you test HTTP calls in Angular?
  9. What is Jasmine, and how is it used in Angular?
  10. How do you write a test case for a directive?

10. Performance Optimization

  1. What are some ways to optimize Angular applications?
  2. How does change detection work in Angular?
  3. What is the OnPush change detection strategy?
  4. How do you lazy load components?
  5. What is preloading in Angular, and how is it used?
  6. How do you optimize Angular templates?
  7. How do you use the Angular Universal for server-side rendering?
  8. What are Angular zones, and how do they work?
  9. How do you reduce bundle size in Angular?
  10. How do you debug performance issues in Angular?

11. Security in Angular

  1. How do you protect against XSS (Cross-Site Scripting) in Angular?
  2. What is DOM sanitization in Angular?
  3. How do you secure Angular applications against CSRF attacks?
  4. What are security risks with Angular templates?
  5. How do you manage authentication in Angular?
  6. What is route guarding in Angular?
  7. How do you implement JWT authentication in Angular?
  8. How do you handle user roles and permissions?
  9. What is content security policy (CSP), and how does it relate to Angular?
  10. How do you secure API calls in Angular?

12. Angular Universal (SSR)

  1. What is Angular Universal?
  2. How does server-side rendering improve performance?
  3. How do you set up Angular Universal?
  4. What is the role of @nguniversal/express-engine?
  5. How do you pre-render Angular pages?
  6. What are the benefits of server-side rendering for SEO?
  7. How does Angular Universal handle dynamic data?
  8. What is the difference between SSR and client-side rendering?
  9. How do you cache server-rendered pages?
  10. What are the challenges of using Angular Universal?

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