Function visibilityChange

visibilityChange(listenerId, fn): void
JMap.Event.Layer.on.visibilityChange

This event is triggered when a tree element visibility changed.
Parameters
- listenerId: string
  Your listener id (must be unique for all layer events)
- fn: ((params) => void)
  Your listener function
  - - (params): void
    - Parameters
      params: JLayerEventVisibilityParams
      Returns void
Returns void
Example
```
// Each time a tree element visibility is changed, will display the new visibility
// in the console
JMap.Event.Layer.on.visibilityChange(
   "custom-visibility-change",
   params => {
     console.log(`Layer element id="${params.layerId}" visible="${params.visibility}"`)
   }
)
```