3. Event Emitter

Implement an EventEmitter class with on, off, and emit methods for event handling.

1. Basic Functionality

• on(event, handler): Register an event handler
• off(event, handler): Remove an event handler
• emit(event, ...args): Emit an event with arguments
• Support multiple handlers for same event
• Pass arguments to handlers

Examples

const emitter = new EventEmitter();

emitter.on('click', (x, y) => {
  console.log(`Clicked at (${x}, ${y})`);
});

emitter.emit('click', 10, 20); // Logs: Clicked at (10, 20)