Question - What is RxJS concatMap?
Answer -
ConcatMap is a combination of 2 operators(concat and map), it lets us mapping a value from a source observable to an observale stream.When the inner observable lets it valoue and pass it down to an observable.It helps in collecting all the emitted values from all of the inner observables and emits it into the subscribers.
Concat is used for taking each form value and in transforming into an observer HTTP,known as inner observer.It also helps in subscribing to the inner observable and also sends the output to the observable result.