code: function (contact) {
          const value = contact.birthday;
          if (value !== null) {
              try {
                  contact.birthday = new Date(parseFloat(value));
  
                // we might get 'Invalid Date' which does not throw an error
                // and is an instance of Date.
                  if (isNaN(contact.birthday.getTime())) {
                      contact.birthday = null;
                  }
              } catch (exception) {
                  console.log('Cordova Contact toCordovaFormat error: exception creating date.');
              }
          }
          return contact;
      }
docs: Converts primitives into Complex Object
  Currently only used for Date fields