Learning Functional Programming in Go

Observer pattern

The observer pattern is one option. It works by injecting a callback object (observer) into the subject to be observed. The subject simply raises an event in all observers when its state changes.

How the observer reacts to the event is outside the scope or care of the subject.

Here’s an implementation of that pattern:

//main.gopackage mainimport (   . "observer")func main() {   subject := Subject{}   oa := Observable{Name: "A"}   ob := Observable{Name: "B"}   subject.AddObserver(&Observer{})   subject.NotifyObservers(oa, ob)   oc := Observable{Name: "C"}   subject.NotifyObservers(oa, ob, oc)   subject.DeleteObserver(&Observer{}) subject.NotifyObservers(oa, ...