var EventEmitter = require('events-bluebird').EventEmitter;

var emitter = new EventEmitter;

emitter.on('event', function(param) {
    return new Promise(function(resolve, reject) {
        setTimeout(function() {
            console.log('first');
            return resolve();
        }, 500);
    });
});

emitter.on('event', function(param) {
    console.log('later');
});

emitter.emitAsyncSeries('event', 'param').then(function(hadListeners) {
    console.log(hadListeners);//true
});

// Output:
// first
// later
// true