For parse a string to a date object we need format module.
function parseDateString() {
// Assuming Date format is MM/DD/YYYY
var initialFormattedDateString = "07/28/2015";
var parsedDateStringAsRawDateObject = format.parse({
value: initialFormattedDateString,
type: format.Type.DATE
});
return parsedDateStringAsRawDateObject;
}