Reactive Streams · interview question
Which operator is the safer default when order must be preserved across asynchronous work?
Multiple choiceMediumchapter-19-curatedpremiumreactive-streamsfunctional-pipelines-flatmap
Answer and explanation
Correct answer
D. concatMap()
Why
concatMap() preserves source ordering by subscribing to one inner publisher at a time. That makes it a better fit than flatMap() when business meaning depends on sequence, even if it sacrifices some concurrency.
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