Observer vs Pub-Sub pattern

Differences between observer pattern and publish-subscribe pattern.

Includes

This repository has included 2 kinds of design patterns in the /packages directory.

1. Observer pattern

2. Publish-Subscribe pattern

Differences

1. In the Observer pattern, the Observers are aware of the Subject, also the Subject maintains a record of the Observers. Whereas, in Publisher/Subscriber, publishers and subscribers don’t need to know each other. They simply communicate with the help of message queues or broker.
2. In Publisher/Subscriber pattern, components are loosely coupled as opposed to Observer pattern. Observer pattern is mostly implemented in a synchronous way, i.e. the Subject calls the appropriate method of all its observers when some event occurs. The Publisher/Subscriber pattern is mostly implemented in an asynchronous way (using message queue).
3. Observer pattern needs to be implemented in a single application address space. On the other hand, the Publisher/Subscriber pattern is more of a cross-application pattern.

Test

• Run all tests

  yarn test

• Observer pattern

  yarn test:observer

• Publish-subscribe pattern

  yarn test:pub-sub

Acknowledgement

1. hackernoon - observer vs pub-sub
2. stackoverflow - Difference between Observer, Pub/Sub, and Data Binding
3. Addy Osmani - Learning JavaScript Design Patterns

License

MIT © Bowen