Function deletion

deletion(listenerId, fn): void
JMap.Event.Feature.on.deletion

This event is triggered when a feature has been deleted.
Parameters
- listenerId: string
  Your listener id (must be unique for all user events)
- fn: ((params) => void)
  Your listener function
  - - (params): void
    - Parameters
      params: JFeatureEventDeleteParams
      Returns void
Returns void
Example
```
// Each time layer features are deleted, this method is processed
JMap.Event.Feature.on.deletion(
   "custom-feature-deletion",
   params => console.info(`For layer id="${params.layerId}", deleted feature ids: ${params.deletedFeatures.map(f => f.id).join(", ")}`)
)
```