EventWatcher

EventWatcher is a core component that provides a flexible event handling system. It allows you to create, bind, and trigger custom events in your application.

Overview

EventWatcher is a generic class that can be used to handle any type of event. It provides a simple and efficient way to implement event-driven architecture in your application.

Features

• Event binding and unbinding
• Event emission
• One-time event listeners
• Type-safe event names
• Generic event data handling
• Cross-component event communication
• Memory leak prevention

Examples

Event Binding and Emission

// Create an event watcher
const watcher = new EventWatcher();

// Bind an event handler
watcher.bind('userLogin', (username) => {
  console.log(`User ${username} logged in`);
});

// Trigger the event
watcher.emit('userLogin', 'john_doe');

One-time Event Listener

const watcher = new EventWatcher();

// Bind a one-time event handler
watcher.once('initializationComplete', () => {
  console.log('Initialization completed');
});

// Trigger the event
watcher.emit('initializationComplete');

Event Unbinding

const watcher = new EventWatcher();

// Bind an event handler
const handler = (data) => console.log(data);
watcher.bind('dataReceived', handler);

// Unbind the event
watcher.unbind('dataReceived');

Best Practices

1. Type Safety

   • Use TypeScript's generic type parameter to ensure type safety for event names
   • Define event types for better code completion and error checking

2. Event Naming

   • Use clear and consistent naming conventions for events
   • Follow a domain-specific naming pattern
   • Document event names and their expected data

3. Memory Management

   • Always unbind events when they are no longer needed to prevent memory leaks
   • Use one-time event listeners for events that should only trigger once
   • Clean up event listeners in component unmount or cleanup functions

4. Error Handling

   • Implement proper error handling in event callbacks
   • Use try-catch blocks for error-prone operations
   • Handle event emission errors gracefully

5. Event Data

   • Keep event data simple and avoid passing large objects
   • Use TypeScript interfaces to define event data structures
   • Validate event data before processing

Related Components

• Process: Uses EventWatcher for process event handling