是否可以使用Node.js EventEmitter同时向所有侦听器发出结束事件？

Question

As the docs says, emitter.emit(event[, arg1][, arg2][, ...])

Synchronously calls each of the listeners registered for event, in the order they were registered, passing the supplied arguments to each.

But with this simple example:

router.get('/messages', function(req, res, next) {
    var addMessageListener = function(res){
        messageBus.once('message', function(data){
            res.json(data);
        })
    }
    addMessageListener(res);
});

router.get('/push', function(req, res, next) {
    messageBus.emit('message', { awesome : 'event'})
    res.status(200).end()
});

When message event is emitted and two request are listening, only one of them listen properly to the event and execute its callback.

Is there a way to emit the event to all listeners at the same time?

edit:

I didnt need the listeners to execute at the exact same time, I just need to execute all of them

edit 2:

After more testing, when I create more than one listener, they are successfully listening to the emitter (debugged with messageBus.listenerCount('message') ) but with an almost 20 seconds delay.

And when only one is listening and the second one is during this delay, if I call /push it successfully emit to the listening one and the other one immediately start listening.

Answer 1

Since you used the once() function to add the listener, node will call the specified listener at most once , and after the first call it will remove that listener. If you are expecting the listener to be called every time a message event is emitted, you need to use the on() function instead of once() .

Answer 2

Ok reading this comment I found that when testing, Chrome will not request the same url again after the first one was responded or after the mentioned delay.

Sorry about that.