ConcatMap interupted when error in one observable

Question

I have the following code:

Observable.from(modifiedNodes)
    .concatMap(node => {
        return this.Model.setData(node);
    })
    .subscribe(() => {
        NodeSaved++;
    }

If setData throws an error for any intermediate node, the next sequence of nodes are not getting resumed. How we can modify it so that even if there is an error for one node, the next sequence of nodes will be executed? I read about onErrorResumeNext but I'm not sure how to use it here.

The method signature for setData is as follows:

public setData(node: INode): Observable<Object>{}

The answer will depend upon what `setData` returns, so you should include at least its signature in the question. — cartant, Jun 06 '17 at 06:40
@cartant I added the signature of setdata(). thanks for your reply — pratRockss, Jun 06 '17 at 07:07

cartant · Accepted Answer · 2019-02-08T00:55:25.540

7

If setData returns an observable, you can use the catch operator. It will receive any errors thrown from within setData and if you return an empty observable, concatMap will move to the next node in the sequence:

import 'rxjs/add/observable/empty';
import 'rxjs/add/operator/catch';

Observable
  .from(modifiedNodes)
  .concatMap(node => this.Model
    .setData(node)
    .catch(error => Observable.empty())
  )
  .subscribe(() => { NodeSaved++; });

edited Feb 08 '19 at 00:55

answered Jun 06 '17 at 07:26

cartant

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thanks for the help. the only thing is I couldn't find empty() method for observable instead I used Observable.of() which worked for me. – pratRockss Jun 06 '17 at 09:44
Added the import for `empty`, too. – cartant Jun 06 '17 at 09:46

ConcatMap interupted when error in one observable

1 Answers1