if layer or feature not found
// deletes the feature id="4" on layer id="3"
JMap.Feature
.deleteById(3, 4)
.then(deletedFeatureId => console.info("Feature id=" + deletedFeatureId + " has been deleted"))
.catch(error => console.error("An error occured", error))
JMap.Feature.deleteById
Deletes the feature for the given layer and feature ids.