Function zoom

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

This event is triggered when zooming on map
Parameters
- listenerId: string
  Your listener id (must be unique for all map events)
- fn: ((params) => void)
  Your listener function
  - - (params): void
    - Parameters
      params: JMapEventZoomParams
      Returns void
Returns void
Example
```
// When the map zoom change, it will display a message in the console
JMap.Event.Map.on.zoom(
   "custom-map-zoom",
   args => console.log(`The map zoom changed (zoom="${args.zoom}")`)
)
```