Knockout js computed - For conversions in form fields between date objects and strings

gistfile1.js

function User() {
    var self = this;
    self.dob = ko.observable('');
}

function UserViewModel() {
    self.user = ko.observable(new User);

    self.dobEdittable = ko.computed({
        read: function() {
            var lastSpacePos = self.user().dob().date.lastIndexOf(" ");
            return self.user().dob().date.substring(0, lastSpacePos);
        },
        write: function(value) {
            self.user().dob(value);
        }
    });
}