What is Observer Pattern?

Updated May 6, 2026

Short answer

A pattern where observers subscribe to subjects to receive updates.

Deep explanation

It decouples producers and consumers. Observers are notified automatically when state changes.

Real-world example

Notification systems in apps.

Common mistakes

  • Tight coupling between subject and observers.

Follow-up questions

  • How is it used in RxJS?
  • What are its limitations?

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