Function getByIds

getByIds(layerId, featureIds): Promise<GeoJSON.Feature[]>
JMap.Feature.getByIds

Returns the features (EPSG:4326 projection) for the given layer and feature ids.
Parameters
- layerId: JId
  the JMap layer id
- featureIds: JId[]
  the array of JMap feature ids
Returns Promise<GeoJSON.Feature[]>
Throws
if layer or any of the features not found

Example
```
// returns the features of layer id="3" and feature id="4", "5" and "6"
JMap.Feature
 .getByIds(3, [4, 5, 6])
 .then(features => console.info("Features has been fetched", features))
 .catch(error => console.error("An error occured", error))
```