Angular Observable

The Angular ExhaustMap maps each value from the source observable into an inner observable, subscribes to it. It then starts emitting the values from it replacing the original value. It then waits for the inner observable to finish. If it receives any new values before the completion of the inner observable it ignores it. It receives a new value after completion of the inner observable, then it creates a new observable. The whole process repeats itself until the source observable is completes

The Angular ConcatMap maps each value from the source observable into an inner observable, subscribes to it, and then starts emitting the values from it replacing the original value. It creates a new inner observable for every value it receives from the Source. It merges the values from all of its inner observables in the order in which they are subscribed and emits the values back into the stream. Unlike SwitchMap, ConcatMap does not cancel any of its inner observables. It is Similar to MergeMap except for one difference that it maintains the order of its inner observables.

The Angular MergeMap maps each value from the source observable into an inner observable, subscribes to it, and then starts emitting the values from it replacing the original value. It creates a new inner observable for every value it receives from the Source. Unlike SwitchMap, MergeMap does not cancel any of its inner observables. It merges the values from all of its inner observables and emits the values back into the stream.

The Angular SwitchMap maps each value from the source observable into an inner observable, subscribes to it, and then starts emitting the values from it. It creates a new inner observable for every value it receives from the Source. Whenever it creates a new inner observable it unsubscribes from all the previously created inner observables. Basically it switches to the newest observable discarding all other.

ThrowError Angular Tutorial ReTry & ReTryWhen   Angular CatchError is an RxJs Operator. We can use it to handle the errors thrown by the Angular Observable. Like all other RxJs operators, the CatchError also takes an observable as input and returns an observable (or throws an error). We can use CatchError to provide a replacement