Event Listeners & Handlers

const event = new CustomEvent('userAction', {
  detail: { userId: 123 },
  bubbles: true,
  cancelable: true
});

Using Event() constructor only
Using dispatchEvent() with any object
Using CustomEvent() constructor and dispatchEvent()
Custom events are created using the CustomEvent constructor and dispatched using dispatchEvent(). The CustomEvent constructor accepts an event type and an options object where you can specify: detail (for custom data), bubbles (if the event should bubble), and cancelable (if the event can be canceled). This is powerful for creating custom component communication or application-wide event systems.
Using fireEvent() method