Observer Pattern Guide

Implement the observer pattern to create loosely coupled systems where objects can subscribe to and receive notifications about state changes. Covers classic observer, event emitters, and connections to reactive programming.

Usage

Ask about implementing the observer pattern in your language, managing subscriptions, or when to prefer observer over other notification patterns.

Examples

• "How do I implement the observer pattern in TypeScript?"
• "What is the difference between observer pattern and pub/sub?"
• "How do I avoid memory leaks with observers?"

Guidelines

• Always provide an unsubscribe mechanism to prevent memory leaks
• Consider using weak references for observer registrations when possible
• Keep notification payloads focused and avoid passing the entire subject state
• Handle exceptions in observers gracefully so one failure doesn't block others
• Use the observer pattern for in-process notifications, pub/sub for cross-process