Function activate

activate(listenerId): void
JMap.Event.MapContext.activate

Activates the listener.

If the listener is already active, does nothing.

If the listener is inactive, it will be reactivated and will be called again ...
Parameters
- listenerId: string
  The listener id
Returns void
Example
```
// activate the listener "my-mapcontext-listener"
JMap.Event.MapContext.activate("my-mapcontext-listener")
```