How to Call `setMaxListeners` when Combining NodeJS Streams

Question

I'm using gulpjs to bundle sets of css files. Each set gets bundled into its own file, so my code looks something like:

var es = require('event-stream');

gulp.task("bundle", function(){
  var streams = [];
  for(var i in sets) {
    var set = sets[i];
    var stream = gulp.src(set.sources)
                     .pipe(...)
                     .pipe(gulp.dest(set.destination));
    streams.push(stream);
  }
  var merged = es.concat.apply(es, streams);
  return merged;
});

So it's been working fine, but now my bundles have gotten big enough that I see the following error:

(node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit.

I've tried to apply answers like this and this but I can't seem to figure out where to call setMaxListeners(0).

How do I call setMaxListeners when I'm merging streams?

Answer 1

It looks like the concern is with the event-stream module (see this issue).

For now, I was able to suppress the issue with this line of code. Of course, this sets the max globally which is not ideal.

require('events').EventEmitter.prototype._maxListeners = 30;

It appears that the issue will be eventually resolved in stream-combiner which is a dependency of event-stream.