Subscribing to the results of a projection

I’m new to EventStore and have what is probably a fairly rudimentary question. When writing a projection that alters state (as opposed to emitting or linking to existing events), how do I subscribe to the eventual results of that projection?

Below is a simple example where I just want to sum up all the adjustments for each inv-*. When the projection is complete, I see how I’m able to “query” the result for each stream (e.g. http://localhost:2113/projection/qtty/state?partition=inv-894111_48311900), however if I understand it correctly I shouldn’t be querying the EventStore and secondly, if I want to create a read mode from these results, I should be creating a subscription to a stream. In this case is the stream “http://localhost:2113/projection/qtty/state”?

$init : function(s,e) {
return { qty : 0 };
$any : function(s,e) {
if ( !== null) {
s.qty += parseInt(;
return s;