Function mapDestroy

mapDestroy(listenerId, fn): void
JMap.Event.Map.on.mapDestroy

This event is triggered when the map is destroyed.
Parameters
- listenerId: string
  Your listener id (must be unique for all map events)
- fn: (() => void)
  Your listener function
  - - (): void
    - Returns void
Returns void
Example
```
// Each time the map is destroyed, will display a message in the console
JMap.Event.Map.on.mapDestroy(
   "custom-map-destroyed",
   () => console.log(`The map has been destroyed`)
)
```