Design Patterns design recommended
Observer Pattern & Pub/Sub
The Observer Pattern establishes a one-to-many dependency between objects, so when one object changes state, all dependents are notified. Includes event-driven and publish/subscribe variations.
- Difficulty
- intermediate
- Read time
- 1 min read
- Version
- v1.0.0
- Confidence
- established
- Last updated
Quick Reference
Observer/Pub-Sub: Decouple event producers from consumers. Observer - subject knows observers directly. Pub/Sub - message broker mediates. Use for: domain events, WebSocket broadcast, UI state updates, async notifications. Always unsubscribe to prevent memory leaks.
Use When
- One-to-many event notification
- Decoupling event producers from consumers
- Cross-cutting concerns (logging, analytics)
- Real-time updates (WebSocket, SSE)
Skip When
- Simple method calls suffice
- Only one consumer exists
- Synchronous, direct communication is better
Observer Pattern & Pub/Sub
The Observer Pattern establishes a one-to-many dependency between objects, so when one object changes state, all dependents are notified. Includes event-driven and publish/subscribe variations.