https://abhishekshukla.dev/tags/reactive/Recent content in Reactive on Abhishek ShuklaHugoen-usSat, 27 Jun 2026 10:00:00 +0530https://abhishekshukla.dev/blog/observer-design-pattern/Sat, 27 Jun 2026 10:00:00 +0530https://abhishekshukla.dev/blog/observer-design-pattern/<p>In modern iOS applications, data is constantly changing. A user logs in, a network request finishes, or a background sync completes. When these events happen, multiple parts of your application—like the UI, analytics trackers, and local databases—need to react immediately.</p> <p>If the object responsible for the data explicitly tells every other object to update, your app becomes a tightly coupled, unmaintainable mess.</p> <p>This is exactly what the <strong>Observer</strong> design pattern prevents. It defines a one-to-many subscription mechanism so that when one object changes state, all its dependents are notified automatically, without the objects needing to know about each other.</p>