I am using the datepicker component (granite/ui/components/foundation/form/datepicker) for a new field in the Touch UI, but it saves it as a String property in the node, rather than a Date. We do querybuilder searches with Dates, and it doesn't seem to work when that field is a String, but it works as a date.
How do I change it so that this component saves this value with type Date rather than String?