How to do sequence maps so that each map waits for the previous in rxjs?

Asked Jan 31 '18 at 09:22

Active Jan 31 '18 at 13:16

Viewed 136 times

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const source = Rx.Observable.from([1, 2, 3, 4, 5]);
const example = source.map(val => { /* asynchronous logic here*/ })
                      .map(val => { /* asynchronous logic here*/ });
                      .map(val => { /* asynchronous logic here*/ });

How to make so that each map waits for the asynchrounous execution of the previous map ?

asked Jan 31 '18 at 09:22

user2080105

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did you take a look at flatmap i think that is what you need [link](https://rahulrsingh09.github.io/AngularConcepts/ngrx/rxjs) – Rahul Singh Jan 31 '18 at 09:24
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use `concatMap` and return an Observable from its callback. – martin Jan 31 '18 at 09:58
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https://stackoverflow.com/questions/43336549/how-to-force-observables-to-execute-in-sequence/43338150#43338150 – martin Jan 31 '18 at 09:59
@martin you are my hero, Please write an answer so that I accept it – user2080105 Jan 31 '18 at 12:56

1 Answers1

2

You should use concatMap instead of map and return Observable from its callback:

const source = Rx.Observable.from([1, 2, 3, 4, 5]);
const example = source
  .concatMap(val => { /* asynchronous logic here*/ })
  .concatMap(val => { /* asynchronous logic here*/ })
  .concatMap(val => { /* asynchronous logic here*/ });

answered Jan 31 '18 at 13:16

martin

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