Pub/Sub design pattern angularjs service

Question

I\'ve been trying to use the answer here posted by Mark Rajcok

angular JS - communicate between non-dependend services

I am having trouble understanding his answ

Answer 1

In his example, NotificationService is a new service that any of the existing services would depend on. He provided an implementation of Service1 but Service2 would essentially be the same...both depend on NotificationService and neither know about each other.

Service1 and Service2 each subscribe to events by calling NotificationService.onEvent1(event1Happened); and trigger events by calling NotificationService.event1Happened(my_data);.