Top 90+ Angular Interview Questions And Answers

1. What is Angular and what are its key features ?
2. What is a Single page application ?
3. What is a component in Angular ?
4. What are the lifecycle hooks in an Angular component ?
5. How to implement routing in Angular web components ?
6. What is lazy loading in Angular ?
7. What are the ways to share data between 2 components ?
8. What are custom directives in Angular and how to create them ?
9. What is the difference between ng serve and npm start ?
10. What is the difference between ng add and npm install ?
11. Can we use jQuery in Angular 2/4/5 ?
12. How to call an API in Angular ?
13. What is the difference between 'dependencies' and 'dev-dependencies' properties in package.json ?
14. What is replay subject in angular ?
15. What is the difference between adding styles and scripts in angular.json and adding styles and scripts in index.html ?
16. What is the difference between cold observables and hot observables ?
17. What are the properties inside @ngModule decorator ?
18. How to generate a component using cli command without creating its spec file ?
19. What is RxJS ?
20. HttpClientModule was introduced in which version of Angular ?
21. Is it necessary to define a constructor in a component ?
22. What are the security features in angular ?
23. What is testbed in Jasmine ?
24. What is the difference between Subject and Behaviour Subject ?
25. What are the advantage of using observable instead of promise for http request ?
26. Difference between authorization and authentication. Explain the basic difference and also in the context of an angular application ?
27. What is AOT in Angular ?
28. How to create custom pipe in Angular ?
29. What are inbuilt Angular pipes ?
30. Explain Software version nomenclature (semantic versioning) ?
31. What is storybook in Angular ?
32. What are the design patterns in Angular ?
33. What are the disadvantages of AOT ?
34. What is the use of tilde(~) and caret(^) sign in package.json ?
35. What are interceptors in Angular ?
36. Can we rename dist folder in Angular Project ?
37. How would the browser Know that your app is an Angular based app ?
38. How to create a custom decorator in Angular ?
39. How to make multiple http calls in parallel in Angular ?
40. What is a module in TypeScript, and how can you use it ?
41. How to hit an API before the loading of the appComponent ?
42. If there is a package(or say library) that is not available through NPM , then how would you use it in your angular application ?
43. How to implement treeshaking in Angular ?
44. What can be the values of 'providedIn' property of @injectable decorator ?
45. How to optimize Angular application using OnPush change detection strategy ?
46. What is the latest Angular version and what are the new features added in it ?
47. What are the types of forms available in Angular ? Explain with syntax.
48. What are dynamic forms and how to create them in Angular ?
49. How to show error messages on form controls ?
50. How to use a service only for a specific component instead of the whole module ?
51. Can you put ngIf and ngFor on same element ?
52. What's the difference between Observable and Subject ?
53. How does ng serve work ?
54. How to improve Angular app performance ?
55. What is AuthGuard in Angular ?
56. Explain the canActivateChild route guard ?
57. What is the difference between Canload and canActivate route guards ?
58. Explain switch map , mergemap , forkjoin, combineLatest, concatMap, exhaustMap . what would happen if any of the requests fails in switch map , merge map or forkjoin ?
59. What is dependency injection ?
60. What's the difference between debounce and setTimeout ?
61. What are RxJS key features ?
62. How do you handle errors in RxJS observables ?
63. How do you implement backpressure in RxJS ?
64. What is the purpose of operators in RxJS, and can you give an example of a common operator ?
65. Can you explain what is the purpose of using schedulers in RxJS, and give an example of a common scheduler ?
66. What is the difference between a pipeable operator and a patch operator in RxJS ?
67. What are services in Angular ?
68. What is the difference between AOT and JIT ?
69. What are the different building blocks of Angular ?
70. How do you use the retry() operator in RxJS, and what is its purpose ?
71. What is Angular change detection and how does it work ?
72. What is zone js in Angular ?
73. How to dynamically create form fields with FormArray in Angular ?
74. What is ngZone in Angular ?
75. Can event triggered in parent cause change detection in child with OnPush strategy in Angular ?
76. Can event triggered in child cause change detection in parent with OnPush strategy in Angular ?
77. How to optimize an Angular application ?
78. Explain pure and impure pipe in Angular ?
79. Explain unit testing in Angular ?
80. How to test an Angular Service ?
81. Explain ngAfterContentInit hooks ?
82. Explain ngAfterViewInit hook with example ?
83. Difference between ngAfterContentInit and ngAfterViewInit ?
84. What is View Encapsulation in Angular ?
85. What is the use of polyfills ?
86. What is scan operator in RxJS ?
87. How does spyOn work in Angular ?
88. How to mock http request in Angular ?
89. What is the difference between 'from' and 'of' operator in RxJS ?
90. What is reduce operator in RxJS ?
91. What is the use of trackBy in Angular ?
    
    
    For more questions and answers visit our website at Frontend Interview Questions