Daily Term: Observer Pattern

Observer Pattern

The Observer Pattern defines a one-to-many dependency where multiple objects (observers) are notified of changes in a subject. For example, in a news app, when a news feed updates (subject), all subscribed users (observers) are notified. It’s implemented using methods like subscribe and notify, promoting loose coupling, but it can lead to memory leaks if observers aren’t properly unsubscribed, and notifications can become inefficient with many observers.

Date: 2025-11-18