Angular

Question 1

✅ Explain Hot and cold observables

Answer 1

N/A

Question 2

✅ 8 building blocks

Answer 2

Module, Components, Templates, Directives, Data-binding, Decorators, Services, Routing

Question 3

✅ What is ChangeDetection?

Answer 3

Default, onPush, ChangeDetectionRef

Question 4

✅ Observable Callback methods (3)

Answer 4

next, error, complete

Question 5

✅ Important things the router does? (4)

Answer 5

URL Structure Lazy loading Guards Redirects / Navigates

Question 6

✅ Event binding vs Property Binding vs Interpolation

Answer 6

N/A

Question 7

✅ What is ngZone?

Answer 7

runOutsideAngular run

Question 8

✅ What is an interceptor?

Answer 8

next.handle()

Question 9

✅ JIT vs AOT

Answer 9

N/A

Question 10

✅ Types of directives (2)

Answer 10

Structural and Directives

Question 11

✅ Component LifeCycle hook

Answer 11

ngOnChanges ngOnInit ngDoCheck ngAfterContentInit ngAfterContentChecked ngAfterViewInit ngAfterViewChecked ngOnDestroy

Question 12

✅ Explain @ViewChild

Answer 12

to find first HTML element matching the selector

Question 13

✅ Differences: Observables vs Promises (4)

Answer 13

Multiple values - Single value Lazy - Not Lazy Cancellable vs Not cancellable Observable has rxjs operators.

Question 14

✅ Custom Two-way binding VS ngModel

Answer 14

ngModel for native elements. custom two-way binding: eg. Input - size Output - sizeChanged

Question 15

✅ Types of subjects

Answer 15

Subject BehaviorSubject ReplaySubject AsyncSubject

Question 16

✅ Constructor (1) vs (2) ngOnInit

Answer 16

Constructor - Inject services ngOnInit - Initialize values - service calls

Question 17

✅ 6 ways to debug

Answer 17

1 - F12 > source > breakpoint on files 2 - debugger; statement 3 - tap on rxjs 4 - redux devtools for ngrx 5 - custom logger 6 - visual studio code extensions

Question 18

✅ ViewEncapsulation

Answer 18

N/A

Question 19

✅ ng-content

Answer 19

N/A

Question 20

⚠️Reactive Forms vs TemplateDriven

Answer 20

⚠️

Question 21

✅ How to prevent memory leaks? (2)

Answer 21

Use Async pipe and kill every subscription

Question 22

✅ Angular Tree Shaking

Answer 22

N/A

Question 23

✅ How to improve the performance of an Angular App? (8)

Answer 23

1- Cache
2 - memoization
3- Use onPush and detach Change detection
4- Lazy loading
5- Update your angular App and CLI
6 - AOT
7. Compress images
8 - Reduce amount of round-trips to the server (http calls)

Question 24

✅ What is Memoization?

Answer 24

if the function is called with the same inputs,
we directly return the result in the cache

Question 25

✅ What is Angular Universal?

Answer 25

Server-Side Rendering (SSR) with Angular

Question 26

✅ How many rxjs operators?

Answer 26

More than 100