Mediator Pattern

Centralizes communication between components through a mediator instead of direct references. Components send messages/events to the mediator, which coordinates responses—reducing coupling and making components independently reusable.

When to Use

• Multiple components need to communicate (UI components, services, handlers)
• Direct component coupling makes testing or reuse difficult
• Orchestrating multi-step workflows (CQRS command/event bus)
• Complex form validation where many fields affect each other

Don't use for:

• Simple parent-child communication (props/callbacks are fine)
• Two components that genuinely belong together
• Systems where central coordination becomes a bottleneck