Wait 'join' event to emit in controller

I built socket factory and injected it to one of my controllers.

```
angular
.module('app')
.factory('socket', socket);

socket.$inject = ['socketFactory', 'authenticationFactory', 'SOCKET_EVENT', 'API'];
function socket(socketFactory, authenticationFactory SOCKET_EVENT, API) {

var socketIO = io.connect(API.SOCKET),
userInfo = authenticationFactory.getUserInfo();

socketIO.on('connect', function() {
if(!userInfo) {
logger.error('No userInfo,logging out!');
authenticationFactory.logout();
return;
}

socketIO.emit('join', { token: userInfo.token });
});

socketIO.on('join', function(data) {
socketIO.emit(SOCKET_EVENT.REQ_MAIN_DATA, { });
});

var mySocket = socketFactory({
ioSocket: socketIO
});

return mySocket;
}
```

Controller:

```
angular
.module('app')
.controller('Controller', Controller);

Controller.$inject = ['socket', 'SOCKET_EVENT'];
function Controller(socket, SOCKET_EVENT) {
var vm = this;
socket.emit(SOCKET_EVENT.REQ_OTHER_DATA);
}
```

The problem is that when I refresh the view where this controller is located, controller fires socket.emit before join event. So how to wait join event's result in controller?