Rx.Observable.prototype.concatMapObserver(onNext, onError, onCompleted, [thisArg]), Rx.Observable.prototype.selectConcatObserver(onNext, onError, onCompleted, [thisArg])

Projects each notification of an observable sequence to an observable sequence and concats the resulting observable sequences into one observable sequence.


  1. onNext (Function): A transform function to apply to each element. The selector is called with the following information:
    1. the value of the element
    2. the index of the element
  2. onError (Function): A transform function to apply when an error occurs in the source sequence.
  3. onCompleted (Function): A transform function to apply when the end of the source sequence is reached.
  4. [thisArg] (Any): Object to use as this when executing the transform functions.


(Observable): An observable sequence whose elements are the result of invoking the one-to-many transform function corresponding to each notification in the input sequence.