Event Aggregator is a software design pattern used to handle communication between different components or modules in an application. It acts as a centralized hub, collecting events from multiple sources and distributing them to interested subscribers, ensuring decoupled and efficient communication.

Key Components:
1. Publisher: Sends events to the Event Aggregator.
2. Subscriber: Registers interest in specific events.
3. Event Aggregator: Manages the distribution of events from publishers to subscribers.

Advantages:
- Decoupling: Reduces direct dependencies between components, making the system more modular.
- Scalability: Handles complex communication patterns efficiently.
- Reusability: Components can be reused in other parts of the system without modification.

Example:
In a typical application, when a user performs an action (e.g., clicking a button), the button component publishes an event. The Event Aggregator forwards this event to all registered subscribers, such as updating the UI or triggering backend processes.

Implementation in Code:
Here’s an example in JavaScript:

javascript
class EventAggregator {
constructor() {
this.events = {};
}

subscribe(eventName, callback) {
if (!this.events[eventName]) {
this.events[eventName] = [];
}
this.events[eventName].push(callback);
}

publish(eventName, data) {
if (this.events[eventName]) {
this.events[eventName].forEach(callback => callback(data));
}
}
}

Applications:

- User Interfaces: Updates UI components dynamically in response to events.
- Microservices: Manages inter-service communication in distributed architectures.
- Game Development: Handles game state changes and interactions efficiently.

By streamlining event handling, the Event Aggregator pattern supports cleaner and more maintainable software designs.