function getLayerGroupName(layer_group) {
  const all_names = [];
  for (let i = 0, ii = layer_group.length; i < ii; i++) {
    all_names.push(layer_group[i].id);
  }
  return `${layer_group[0].source}-${all_names.join(',')}`;
}
function getLayerGroupName(layer_group) {
  const all_names = [];
  for (let i = 0, ii = layer_group.length; i < ii; i++) {
    all_names.push(layer_group[i].id);
  }
  return `${layer_group[0].source}-${all_names.join(',')}`;
}
function getLayerGroupName ( layer_group ) { const all_names = [ ] ; for ( let i = 0 , ii = layer_group . length ; i < ii ; i ++ ) { all_names . push ( layer_group [ i ] . id ) ; } return ` ${ layer_group [ 0 ] . source } ${ all_names . join ( ',' ) } ` ; }
Create a unique key for a group of layers
@param {Object[]} layer_group An array of Mapbox GL layers.

@returns {string} The layer_group source name, followed by a concatenated string of layer ids.
Create a unique key for a group of layers @param { Object [] } layer_group An array of Mapbox GL layers .