Number of events being published grows with sub to EventBus in saga about cqrs

[jsonberry]

Ah yes @kamilmysliwiec my bad, this was all simply due to using a mergeMap and returning a hot observable.

This was just an Rx oversight on my part, thank you for taking the time to respond.

[jsonberry]

@mark-beeby If you are pulling in the eventBus into a Saga, just like I had in these examples, you'll need to use something like a take(1).

This is because that Observable, the one that's being returned inside the mergeMap, needs to complete, and if you return a hot Observable (like a Subject) it won't complete. There are some nuances there, but I'm just trying to get straight to the point :)

If you don't "complete", every time the Saga runs, a new subscription to the eventBus is created and is added to any previous times the Saga ran, thus you get multiple events. When you take(1), it'll close the subscription on the eventBus and you won't pile up with events you aren't expecting.

cold Observables, like of('foo') or from(apiCall) would complete automatically thus bypassing the "additional" and unnecessary subscriptions.

[kamilmysliwiec]

Inside your SomeWriteModel.create method, I'd suggest checking your array of pending events (this.getUncommittedEvents() - this method is inherited from AgreggateRoot). If this array is empty, your saga logic is probably wrong. Otherwise, commit() works unexpectedly (doesn't clean the array after publishing events).

[mark-beeby]

@jsonberry did you have any hints on returning a cold observable? New to Rx here and struggling with the same problems.
Cheers!