From Wikipedia: The observer pattern is a software design pattern in which an object, named the subject, maintains a list of its dependents, called observers, and notifies them automatically of any state changes, usually by calling one of their methods.

ReactiveX is a project that implements this useful pattern in several programming languages, including JavaScript and Go.

For example, I designed a site that had an event (a button clicked) that updated text throughout the site. I did this by making the button "Observable" and subscribing listeners using the RxJS JavaScript library.

The RxGo package for Go is particularly useful because it takes advantage of Go's channels to add lots of functional programming idioms to the language, like Maps and Filters. RxGo is a natural fit for the language.

If this looks like it could be useful to you, let me know.