Observer Design Pattern

Making use of the Observer Design pattern

RxJS uses the Observer Design pattern, an official design pattern from the Gang of Four.

📝 Note: The Gang of Four is in reference to a group of four developers, Erich Gamma, Richard Helms, Ralph Johnson, and John Vlissides, who in 1994 worked together on a book called Design Patterns: Elements of Reusable object-orientated Programming. Here, they set out 23 design patterns or approaches for writing good object-orientated software, which, in their opinion, had some major problems at that time.

This book has become a classic computer programming book, and now over 25 years later, the approaches they described in this book are still being used, including the Observer Design pattern.