If you need to generate, filter or transform your search query you can extract all the logic in a separate class that implements the Iivannov\Larasquare\Filter\FilterContract
and then just inject it with setFilter() method.
Put your filter logic in the parse() method. It will automatically receive the query passed in the search methods.
You can overwrite values, generate values from your custom array or whatever you need. The returned array will be sent with the Foursquare request.