Differences Between Observer and Publish/Subscribe Patterns
Aspect |
Observer Method |
Publish/Subscribe Pattern |
---|---|---|
Communication |
Subject directly notifies observers when an event occurs. |
Message broker (or event bus) acts as an intermediary between publishers and subscribers. |
Event Type |
Typically focuses on a single event (e.g., temperature change). |
Supports multiple event types; subscribers can choose to subscribe to specific event types. |
Flexibility |
Loose coupling between subjects and observers. |
Offers flexibility for decoupling among different publishers and subscribers. |
Reuse |
Observers can be reused across different subjects. |
Can be used to decouple various components in a system. |
Memory Management |
Memory management can be simpler due to a straightforward relationship between subjects and observers. |
Requires proper management of event subscriptions and unsubscriptions to prevent memory leaks. |
Performance |
Generally lower performance overhead since it directly invokes observer methods. |
Slightly higher performance overhead due to the involvement of a message broker. |
Observer Method – JavaScript Design Pattern
Observer design pattern, a staple of behavioral design patterns in JavaScript, provides a means to establish a one-to-many relationship between objects. This design pattern is especially valuable for decoupling components and facilitating extensibility in software applications. By employing this pattern, you can have one object (the subject) notify multiple observers (subscribers) about changes or events without requiring them to have direct knowledge of each other. This decoupling enhances maintainability and extensibility in your software projects.
Important Topics for Observer Method in JavaScript
- Participants of Observer Pattern in JavaScript:
- Implementation of Observer Method:
- Diagram Explanation of Observer Method in JavaScript
- Publish/Subscribe Pattern:
- Differences Between Observer and Publish/Subscribe Patterns:
- Advantages of the Observer Method:
- Disadvantages of the Observer Method:
- Conclusion :