apache/cordova-wp8 — pull request #8 by kevfromireland (2013-05-28 17:13:10+00:00)
Title: CB-3522: Deal with the case where the user has specified partial options

I think the user should be able to specify a partial options object as the documentation suggests that will be OK. From the docs:

Options

filter: The search string used to filter contacts. (DOMString) (Default: "")
multiple: Determines if the find operation should return multiple contacts. (Boolean) (Default: false)