RxJS MCQs with answers Page - 2

Here, you will find a collection of MCQ questions on RxJS. Go through these questions to enhance your preparation for upcoming examinations and interviews.

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F

Fox Root • 490 Points
Goal Maker

Q. Which operator merges emissions from multiple Observables?

  • (A) merge()
  • (B) map()
  • (C) take()
  • (D) pluck()

F

Fox Root • 490 Points
Goal Maker

Q. Which operator limits the number of emissions?

  • (A) take()
  • (B) skip()
  • (C) tap()
  • (D) finalize()

F

Fox Root • 490 Points
Goal Maker

Q. What happens when unsubscribe() is called?

  • (A) Observable restarts
  • (B) Subscription is cancelled and resources are released
  • (C) Error occurs
  • (D) Data is cached

F

Fox Root • 490 Points
Goal Maker

Q. Which creation function emits values at regular intervals?

  • (A) timer()
  • (B) interval()
  • (C) range()
  • (D) of()

F

Fox Root • 490 Points
Goal Maker

Q. Which operator handles errors in a stream?

  • (A) catchError()
  • (B) retry()
  • (C) throwError()
  • (D) map()

F

Fox Root • 490 Points
Goal Maker

Q. Which operator cancels the previous inner Observable?

  • (A) mergeMap()
  • (B) concatMap()
  • (C) switchMap()
  • (D) exhaustMap()

F

Fox Root • 490 Points
Goal Maker

Q. What does of() do in RxJS?

  • (A) Creates an Observable from provided values
  • (B) Fetches HTTP data
  • (C) Stops execution
  • (D) Creates a Promise

F

Fox Root • 490 Points
Goal Maker

Q. Which operator performs an action when the stream completes?

  • (A) tap()
  • (B) finalize()
  • (C) filter()
  • (D) map()

F

Fox Root • 490 Points
Goal Maker

Q. What is the main advantage of RxJS?

  • (A) Improves CSS performance
  • (B) Simplifies asynchronous and event-based programming
  • (C) Replaces databases
  • (D) Compiles TypeScript

F

Fox Root • 490 Points
Goal Maker

Q. Which RxJS operator collects all emitted values into a single array when the source completes?

  • (A) scan()
  • (B) toArray()
  • (C) reduce()
  • (D) buffer()

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