public function updateOptions($modelName)
{
$fieldFactory = app('admin_field_factory');
$response = array();
//iterate over the supplied constrained fields
foreach ($this->request->input('fields', array()) as $field) {
//get the constraints, the search term, and the currently-selected items
$constraints = array_get($field, 'constraints', array());
$term = array_get($field, 'term', array());
$type = array_get($field, 'type', false);
$fieldName = array_get($field, 'field', false);
$selectedItems = array_get($field, 'selectedItems', false);
$response[$fieldName] = $fieldFactory->updateRelationshipOptions($fieldName, $type, $constraints, $selectedItems, $term);
}
return response()->json($response);
}