Function creation

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

This event is triggered when a feature has been created.
Parameters
- listenerId: string
  Your listener id (must be unique for all user events)
- fn: ((params) => void)
  Your listener function
  - - (params): void
    - Parameters
      params: JFeatureEventCreateParams
      Returns void
Returns void
Example
```
// Each time a feature is created, this method is processed
JMap.Event.Feature.on.creation(
   "custom-feature-creation",
   params => console.info(`For layer id="${params.layerId}", feature id="${params.featureId}" geometry has been created`)
)
```