KnockoutJS form validation always return valid - json

Question

I have a form:
And implements KnockoutJS Validation. Everything is applied by following the documentation but it always return that is valid even when I leave empty fields, etc.
This is the code:
ko.validation.rules.pattern.message = 'Invalid.';
ko.validation.configure({
registerExtenders: true,
messagesOnModified: true,
insertMessages: true,
parseInputAttributes: true,
messageTemplate: null
});
var initialData = [
{ firstName: "John", fathersLast: "Smith", country : ""
}
];
var Contact = function (contact) {
var self = this;
self.firstName = ko.observable(contact.firstName ).extend({ required: true, message: '* required' });;
self.fathersLast = ko.observable(contact.fathersLast ).extend({ required: true, message: '* required' });;
self.country = ko.observable(contact.country ).extend({ required: true, minLength: 2, message: '* required' });
};
var ContactsModel = function(contacts) {
var self = this;
self.contacts = ko.observableArray(ko.utils.arrayMap(contacts, function(i) {
return new Contact(i);
}));
self.errors = ko.validation.group(self.contacts);
self.addContact = function() {
if (self.errors().length == 0) {
alert('Thank you.');
} else {
alert('Please check your submission.');
self.errors.showAllMessages();
}
self.contacts.push({
firstName: "",
fathersLast: "",
country: ""
});
};
self.removeContact = function(contact) {
self.contacts.remove(contact);
};
};
ko.applyBindings(new ContactsModel(initialData));
Here is the working example: http://jsfiddle.net/8Hude/3/
Any clue why It's not working right?
Thanks.

Answer 1

As stated already, the validation plugin will be the most elegant, less re-inventive solution.
Edit: After commentary implementation utilizing validation plugin
With that aside, you have a couple options.
If you are confident the contact object will always contain only required fields, a not very robust implementation would be iterate over the properties of the contact ensuring each has some value.
A little more robust, but still lacking the elegance of the plugin, implementation would be to maintain an array of required fields and use that array for validation. You can reference my example for this setup. Essentially, each required property is mapped to observables. Changes made to the value of any observable property triggers (via a subscription) a mutation call for a dummy observable that is used in a computed. This is required since a computed can't call valueHasMutated. The mutation call triggers the computed to reevaluate, thus updating the UI.