100+ Angular Interview questions and answers for Junior and Senior level developers
”
StoryLine:
“Each interview will give different experience. Whenever we prepare for any technical interviews, we will cover various topics from basic concepts to tricky questions. Enrichvia will share the experience from many developers who faced technical interview in Angular.”
Content:
Top 100+ Angular Interview Questions and Answers for experienced in all levels
#basics
* What is the latest version of Angular?
* What are the latest features of recent version of Angular?
* When you will use ngOnDestroy and ngAfterViewInit?
* Difference between contentChild and viewChild?
* Difference between templateRef and elementRef?
* What are the different type of Decorators in Angular?
* What are pipes in Angular and how do we create custom Pipe?
* Explain Dependencies injection? Give example to implement the feature.
* Brief different types of change detection methods?
* How angular differ from other frameworks?
* Difference between ng-template and ng-container?
* How to check html version in angular application?
* Explain Data binding in angular?
* Explain the types of decorators in Angular?
* Explain in detail about Angular project that how you will create create, build, deploy app?
* What is difference between ng-template and ng-content?
* What happens when we use the script tag within a template?
* What is transpiling?
* What is the use of polyfills?
* What is ngZone in Angular?
#components
* How will you create dyanamic components?
* How so we communicate between components explain with example.
* Explain Directive and their types?
* How will you create custom directive and use in Template?
#dependency_Injection
* Difference between ProvideIn(“Root”) and ProvideIn(“any”)
#lifecycle_hooks
* What are Life cycle hooks in Angular?
* Explain ngAfterViewInit hook with example?
#routing
* What are interceptors and how to implement it?
* Difference between forRoot and forChild in Routing?
* How to implement authentication and authorization. If we have a role of admin and user then how to handle it?
* Explain about Route guard and different types of it?
#performance
* What are the different ways to improve app performance?
* What is the difference betweekn AOT && JIT? Which one is better?
* How to implement Lazy loading feature?
* How to implement eager loading feature?
* Difference between Eager loading and Lazy loading?
#configuration
* What is the use of angular.json?
* What is the use of tsconfig.json?
* What is the use of package.json?
* What is the use of tslint.json?
* What is the use of karma.conf.js?
* How will you set different enrvironment for testing?
* How will you generate component in terminal?
* How will you generate service in terminal?
* How will you generate pipe in terminal?
#data-sharing
* What are the ways you can share data in Angular?
#forms
* Reactive forms and Template forms?
* Custom validator in reactive forms?
* Types of form in angular and its use case what is DOM?
* Difference between form builder and form group?
#reactiveProgramming
* What is Observables and Promises?
* How many types of observable in Angular?
* What is the difference between Share and ShareReplay?
* What is the difference between AsyncSubject and Subject?
* How to handle multiple HTTP calls parallely?
* Diferrence between switchMap and mergeMap?
* Diferrence between exhaustMap and concatMap?
* What is the use of operators in rxjs?
* What is subject and behavior subject? Use case of these two.
* What are cold observables in rxjs?
* What are RxJS operators have you used?
* What is the use of debouncetime operator?
* What do you meant by forkJoin Operator?
* Have you worked with RxJS operators, explain, while explaining they asked in which scenarios we use concatmap, switchmap, forkjoin, mergemap?
* How do you deal with errors in observables?
* What is reduce operator in RxJS?
* How to combine HTTP calls response?
* Tell us the difference between switchMap, mergeMap, exhaustMap and concatMap.
#ngrx
* What is ngRx? Advantages and Disadvantages of it?
* What is difference between Action and Reducers?
#unit-testing
* Unit test cases methods in angular?
* How to add test case for a service?
* How will you test an Angular Service?
* How does spyOn work in Angular?
#upgrade
* How will you upgrade Angular 15 to Latest? Explain the steps involved in it?
* Is it possible to upgrade Angular JS to Angular? If yes, explain the steps?
#generic
Angular Coding level questions to practice for interviews:
1. Custom Pipe Question: Uppercase First Letter
Question: Write a custom pipe in Angular called CapitalizePipe that takes a string as input and returns the string with the first letter of each word capitalized. For example, if the input is “hello world”, the output should be “Hello World”.
2. Implement a Simple Custom Directive
Question: Write a custom directive called highlightOnHover that changes the background color of an element when hovered.
3. Set Up Reactive Form with Validation
Question: Create a simple reactive form for a login page with fields for email and password. Add validation to require both fields, and validate that the email field has a valid email format.
4. Create a Simple HTTP Service
Question: Create a service that makes an HTTP GET request to fetch a list of users from a URL. Write the service and demonstrate its usage in a component.
5. Create a Simple Component with Input and Output
Question: Create a component called CounterComponent that has an input to set an initial count and an output event to emit the updated count each time a button is clicked to increment the count.
What is the main purpose of Angular?
2. What are directives in Angular and how many types of directives exist?
3. Explain data bindings and the different types.
4. What are the basic components involved in Angular?
5. What’s the difference between AngularJS and Angular?
6. What are components and modules in Angular?
7. What are decorators in Angular?
8. What is metadata or annotations in Angular?
9. What are templates in Angular?
10. What is SPA and how do you implement it in Angular?
11. Explain the importance of routing in Angular & how to implement it.
12. What is lazy loading in Angular?
13. How do you implement lazy loading in Angular?
14. What is Node.js?
15. What is NPM?
16. Why is the node_modules folder important?
17. What is package.json?
18. What is TypeScript?
19. What is the need for Angular CLI?
20. What are services in Angular?
21. When would you use content projection?
22. Explain content projection slots in Angular.
23. Why do we need ViewChild and ViewChildren in Angular?
24. What is a template reference variable?
25. Explain ContentChild and ContentChildren.
26. Differentiate between ViewChild, ViewChildren, ContentChild, and ContentChildren.
27. What is { static: true } in ViewChild?
28. What is the importance of Angular component hooks/life cycles?
29. Explain Angular life cycle hooks in detail.
30. Differentiate between constructor and ngOnInit().
31. How do you implement lazy loading in Angular?
32. How do you implement HTTP in Angular?
33. How do you pass data between components?
34. What are pipes in Angular?
35. Can you give examples of inbuilt Angular pipes?
36. How do you write a custom pipe?
37. What is RxJs and why is it needed?
38. What are observables and observers?
39. What is a stream in RxJs?
40. What is the use of subscribe in RxJs?
41. How do you unsubscribe from a stream?
42. What are operators in RxJs?
43. Where have you used RxJs in Angular?
44. Differentiate between RxJs and Promises.
45. How do you install RxJs?
46. Why is RxJs called push/reactive and not pull/imperative?
47. Name some RxJs operators.
48. What are interceptors in Angular?
49. How do you implement interceptors?
50. What are some uses of interceptors, and can we provide multi-interceptors?
Conclusion:
Angular developers have huge market all over world. They can enrich web with UI web development for all sectors based on client needs. Becoming NodeJS should have good knowledge in HTML, CSS, JavaScript.
