RxJs - Interview Questions and Answers for 'RxJs' | Search Interview Question

RxJs - Interview Questions and Answers for 'RxJs' - 13 question(s) found - Order By Newest

Q1. What is the difference between subject and observable ?

Ans. Subject has state, it keeps a list of observers. On the other hand, an Observable is really just a function that sets up observation. While Subjects are Observables, Subjects also implement an Observer interface.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve RxJava Design Design Pattern}

Q2. What is the difference between Observer and Observable ?

RxJava

Ans. Observable is emiting data and Observer is subscribing to catch the data

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve RxJava Design Deaign Pattern}

Q3. What is the difference between subscribe and blockingSubscribe method ?

RxJava

Ans. blockingSubscribe will block the current thread and wait till the chain completes

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q4. Difference between concatMap and flatMap ?

RxJava

Ans. Flatmap converts stream(s) into a single streams without maintaining a order where as concatmap does the same along with maintaining the order

flatmap example -[[1,2,3],[4,5,6],[7,8,9]] -> [1,4,7,2,5,8,3,6,9]

concatmap example -[[1,2,3],[4,5,6],[7,8,9]] -> [1,2,3,4,5,6,7,8,9]

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q5. What are the drawbacks of Reactive extensions ?

ReactiveX

Ans. Reactive extensions have a steep learning curve which makes it confusing for beginner and intermediate developers.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve RxJava ReactiveX Reactive Programming}

Q6. What is the difference between subscribe and unsubscribe ?

Angular

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve RxJs subscribe vs unsubscribe}

Q7. What does pipe does on an observable ?

RxJs

Ans. With pipe we specify the operator function to which this observable is passed for transforming the observable.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Angular Observable}

Q8. What do we specify within the pipe method ?

RxJs

Ans. Operator function to which an observable is passed for transformation.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Angular}

Q9. Why do we do transformation on the observable itself rather than doing it in the subscriber ?

RxJs

Ans. Because that way we just need to do that transformation at one place and not within each subscriber. Single source of truth.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Angular Observable Suscriber}

Q10. Can we specify multiple functions in the pipe ? What happens if we do it ?

RxJs

Ans. Yes, We can specify multiple functions within pipe method. In that case first function get's called with the observable , the response if then passed to the second method and so on.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Angular}

Q11. Can we specify multiple maps within pipe ?

RxJs

Ans. Yes, it's same as passing multiple methods within pipe. Output of one map is passed to second and so on.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Angular}

Q12. How can we sort an observable of a user array on user name ( name being one of the field of user ) ?

RxJs

Ans. userArrayObservable.pipe(
map(userArray => {
return userArray.sort(comparator);
});
)

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Angular}

Q13. What does the pipe method return in Rxjs ?

RxJs

Ans. Pipe method is performed on an observable with the argument as a function. It returns the transformed observable with transformation being done by the specified method.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Search Interview Questions

Help us and Others Improve. Please let us know the questions asked in any of your previous interview.