promise-event

var promiseEvent = require('promise-event');
var EventEmitter = require('events').EventEmitter;
var emitter = new EventEmitter();

emitter = promiseEvent(emitter);

emitter.on('hello', function *(world) {
  //...
});

emitter.emit('hello', 'world').then(function () {
  //...
});

co(function *() {
  yield emitter.emit('hello', 'world');
});