API: Get item listing by type: folder or file?

Looking at the Box API, I wish to find a way to get a listing of items in a folder for a specific type, for example, the type is either folder or file.

What I have reviewed:

• /folders/folder_id/items, it is not clear if I can not restrict the search for items by type folder or file.
• /search, is promising, however, it parameter query is required, when I only need parameters type and ancestor_folder_ids

Suggestions?