BUG? State not being modified in projection

EventStoreDB
1

Hello,

I’m new to EventStore. I’ve been trying to use the projections example, from multiple streams. I named the streams user-(uuid4) and each of them has one UserCreated event.

The problem is that userCount does not increase. On the projection page both state and results are empty, but when I go to debug and do step-by-step, I see the initial state as 0, but no matter how many events I play, it doesn’t change.

On debug mode, I can see the event list in the category properly and every time I run a step it gets reduced. I tried to console.log before and after the increment and the variable is being properly changed, but it seems that the scope is local.

I’m following this approach (http://docs.geteventstore.com/introduction/3.8.1/projections/):

fromCategory('user')
  .foreachStream()
  .when({
    '$init': function(state, ev) {
      return { userCount: 0 }
    },
    'UserCreated': function(state, ev) {
      state.userCount++
    }
  })
2

There is an explanation about what you are seeing in this issue https://github.com/EventStore/EventStore/issues/699
If you have any further issues, please don’t hesitate to shout.

3

Thanks for super fast reply.

I read what you mentioned. What makes it very weird is that I’m using the ES UI, and there is a state and results fields and they’re both empty. And I can’t select the partition from there. I dont want to partition BTW, I want to count all events from all streams from this category

4

It works with fromAll, but it doesn’t specify at all that this is from my user category. What if in another context I have event with the same name?

5

If you don’t want to create a partition, you can just change your projection to not use foreachStream.
e.g.

fromCategory('user')
  .when({
    '$init': function(state, ev) {
      return { userCount: 0 }
    },
    'UserCreated': function(state, ev) {
      state.userCount++

    }
  })

``