public ViewsDataHelper::fetchFields($base, $type, $grouping = FALSE, $sub_type = NULL)
Fetches a list of all fields available for a given base type.
Parameters
(array|string) $base: A list or a single base_table, for example node.
string $type: The handler type, for example field or filter.
bool $grouping: Should the result grouping by its 'group' label.
string $sub_type: An optional sub type. E.g. Allows making an area plugin available for header only, instead of header, footer, and empty reg