Merge rxjs5 and errors

Question

I would like to merge / merge several Observables, and when each of them is done, execute the finally function. It seems that the operator mergeexecutes each subscription in parallel, and this is what I need, but if any of them causes an error, execution stops.

RxJS version 4 has a mergeDelayError operator , which should support the execution of all signatures until all of them are completed, but this operator is not implemented in version 5.

Should I return to another operator?

var source1 = Rx.Observable.of(1,2,3).delay(3000);
var source2 = Rx.Observable.throw(new Error('woops'));
var source3 = Rx.Observable.of(4,5,6).delay(1000);

// Combine the 3 sources into 1 

var source = Rx.Observable
  .merge(source1, source2, source3)
  .finally(() => {

    // finally is executed before all 
    // subscriptions are completed.

    console.log('finally');

  }); 

var subscription = source.subscribe(
  x => console.log('next:', x),
  e => console.log('error:', e),
  () => console.log('completed'));

Jsbin

Answer 1

, , catch(). :

const sources = [source1, source2, source3].map(obs => 
  obs.catch(() => Observable.empty())
);

Rx.Observable
  .merge(sources)
  .finally(...)
  ...

Answer 2

, , :

const mergeDelayErrors = [];
const sources = [source1, source2, source3].map(obs => obs.catch((error) => {
  mergeDelayErrors.push(error);
  return Rx.Observable.empty();
}));

return Rx.Observable
  .merge(...sources)
  .toArray()
  .flatMap(allEmissions => {
    let spreadObs = Rx.Observable.of(...allEmissions);
    if (mergeDelayErrors.length) {
      spreadObs = spreadObs.concat(Rx.Observable.throw(mergeDelayErrors));
    }
    return spreadObs;
  })

CompositeError. , mergeDelayErrors .

, , , , , , . , , mergeDelayError, , .

Answer 3

, .

function mergeDelayError(...sources) {
  const errors = [];
  const catching = sources.map(obs => obs.catch(e => {
    errors.push(e);
    return Rx.Observable.empty();
  }));
  return Rx.Observable
    .merge(...catching)
    .concat(Rx.Observable.defer(
      () => errors.length === 0 ? Rx.Observable.empty() : Rx.Observable.throw(errors)));
}


const source1 = Rx.Observable.of(1,2,3);
const source2 = Rx.Observable.throw(new Error('woops'));
const source3 = Rx.Observable.of(4,5,6);

mergeDelayError(source1, source2, source3).subscribe(
  x => console.log('next:', x),
  e => console.log('error:', e),
  () => console.log('completed'));